@phdthesis{Krause2005,
  author    = {Krause, Stefan},
  title     = {Untersuchung und Modellierung von Wasserhaushalt und Stofftransportprozessen in grundwassergepr{\"a}gten Landschaften am Beispiel der Unteren Havel},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-3487},
  school      = {Universit{\"a}t Potsdam},
  year      = {2005},
  abstract  = {Das Ziel dieser Arbeit ist die Untersuchung der Wasserhaushaltsprozesse und Stofftransportvorg{\"a}nge innerhalb der grundwassergepr{\"a}gten Talauenlandschaften von Tieflandeinzugsgebieten am Beispiel der im Nordostdeutschen Tiefland gelegenen Havel. Die Arbeiten in verschieden skaligen Teileinzugsgebieten der Havel besch{\"a}ftigen sich dabei zum einen mit der experimentellen Untersuchung und vorrangig qualitativen Beschreibung der Wasserhaushaltsdynamik, zum anderen mit der Entwicklung eines zur quantitativen Analyse von Wasserhaushalts- und Stofftransportprozessen geeigneten Modells und der anschließenden Modellsimulation von Wasserhaushalt und Stickstoffmetabolik im Grundwasser sowie der Simulation von Landnutzungs- und Gew{\"a}sserstrukturszenarien. F{\"u}r die experimentelle Untersuchung der Abflussbildung und der Wasserhaushaltsprozesse in den Talauenlandschaften des Haveleinzugsgebiets wurde Einzugsgebiet der \&\#8221;Unteren Havel Niederung\&\#8220; ein umfangreiches Messnetz installiert. Dabei wurden an mehreren Messstationen und Pegeln meteorologische Parameter, Bodenfeuchte sowie Grundwasserst{\"a}nde und Abfl{\"u}sse beobachtet. Die Analyse der Messergebnisse f{\"u}hrte zu einem verbesserten Verst{\"a}ndnis von Wasserhaushaltsprozessen in der durch das oberfl{\"a}chennahe Grundwasser und die Oberfl{\"a}chengew{\"a}sserdynamik beeinflussten Talauenzone. Dar{\"u}ber hinaus konnten durch die Implementierung der Messergebnisse konsistente Anfangs- und Randbedingungen f{\"u}r die Wasserhaushalts- und Grundwassermodellierung im Modellkonzept IWAN realisiert werden. Mit dem Modell IWAN (Integrated Modelling of Water Balance and Nutrient Dynamics) wurde ein Werkzeug geschaffen, welches die Ber{\"u}cksichtigung spezifischer hydrologischer Eigenschaften von Tieflandauen, wie z. B. den Einfluss des oberfl{\"a}chennahen Grundwassers bzw. der Dynamik von Oberfl{\"a}chenwasserst{\"a}nden auf den Wasserhaushalt, erm{\"o}glicht. Es basiert auf der Kopplung des deterministischen distribuierten hydrologischen Modells WASIM-ETH mit dem dreidimensionalen Finite-Differenzen-basierten Grundwassermodel MODFLOW. Die Modellierung der Stickstoffmetabolik im Grundwasser erfolgt durch das mit Grundwassermodell gekoppelte Stofftransportmodel MT3D. Zur modellbasierten Simulation des Wasserhaushalts der Tieflandauenlandschaften wurde das Modellkonzept IWAN f{\"u}r verschieden skalige Teileinzugsgebiete an der Havel f{\"u}r Simulationszeitr{\"a}ume von 2 Wochen bis zu 13 Jahren angewandt. Dabei wurden die Teilmodelle f{\"u}r Wasserhaushalts- und Grundwassermodellierung in zwei unterschiedlichen Teileinzugsgebieten der \&\#8221;Unteren Havel Niederung\&\#8220; kalibriert. Die anschließende Validierung erfolgte f{\"u}r das gesamte Einzugsgebiet der \&\#8221;Unteren Havel\&\#8220;. Die Unsicherheiten des Modellansatzes sowie die Anwendbarkeit des Modells im Untersuchungsraum wurden gepr{\"u}ft und die Limitierung der {\"U}bertragbarkeit auf andere grundwasserbeeinflusste Tieflandeinzugsgebiete analysiert. Die Ergebnisse der Wasserhaushaltssimulationen f{\"u}hren einerseits zum erweiterten Prozessverst{\"a}ndnis des Wasserhaushalts in Flachlandeinzugsgebieten, andererseits erm{\"o}glichten sie durch die Quantifizierung einzelner Prozessgr{\"o}ßen die Beurteilung der Steuerungsfunktion einzelner Wasserhaushaltsprozesse. Auf der Basis lokaler Simulationsergebnisse sowie geomorphologischer und gew{\"a}ssermorphologischer Analysen wurde ein Algorithmus entwickelt, welcher die Abgrenzung des direkten Eigeneinzugsgebiets der Havel als Raum der direkten Interaktion zwischen Oberfl{\"a}chengew{\"a}sser und umgebendem Einzugsgebiet beschreibt. Durch Simulation des Wasserhaushalts im Eigeneinzugsgebiet mit dem Modell IWAN konnten die Interaktionsprozesse zwischen Fluss und Talauenlandschaft quantitativ beschrieben werden. Dies erm{\"o}glichte eine Bewertung der Abflussanteile aus dem Eigeneinzugsgebiet sowie eine Quantifizierung der zeitlich variablen Retentionskapazit{\"a}t der Auenlandschaft w{\"a}hrend Hochwasserereignissen. Zur Absch{\"a}tzung des Einflusses ver{\"a}nderter Landnutzung und angepassten Managements auf den Wasserhaushalt der Talaue wurden Szenarien entwickelt, welche {\"A}nderungen der Landnutzung sowie der Gew{\"a}ssergeometrie implizieren. Die Simulation des Wasserhaushalts unter jeweiligen Szenariobedingungen erm{\"o}glichte die detaillierte Analyse sich {\"a}ndernder Randbedingungen auf den Gebietswasserhaushalt und auf die Austauschprozesse zwischen Grundwasser und Oberfl{\"a}chengew{\"a}sser. Zur Untersuchung der Stickstoffmetabolik im Grundwasser der Talauenlandschaft wurde das im Modellkonzept IWAN integrierte Stofftransportmodell MT3D f{\"u}r das Eigeneinzugsgebiet der Havel angewandt. Dies erm{\"o}glichte eine Bilanzierung der aus dem Grundwasser des Eigeneinzugsgebiets stammenden Nitratfrachtanteile der Havel sowie von Nitratkonzentrationen im Grundwasser. Szenariensimulationen, welche verminderte Nitrateintr{\"a}ge aus der durchwurzelten Bodenzone annehmen, erm{\"o}glichten die Quantifizierung der Effizienz von Managementmaßnahmen und Landnutzungs{\"a}nderungen in Hinblick auf die Minimierung von Eintr{\"a}gen in Grundwasser und Oberfl{\"a}chengew{\"a}sser.},
  subject      = {Grundwasser},
  language  = {de}
}
@phdthesis{Niehoff2001,
  author    = {Niehoff, Daniel},
  title     = {Modellierung des Einflusses der Landnutzung auf die Hochwasserentstehung in der Mesoskala},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0000148},
  school      = {Universit{\"a}t Potsdam},
  year      = {2001},
  abstract  = {Seit 1990 waren mehrere der großen Flussgebiete Mitteleuropas wiederholt von extremen Hochwassern betroffen. Da sowohl die Landoberfl{\"a}che als auch die Flusssysteme weiter Teile Mitteleuropas in der Vergangenheit weitreichenden Eingriffen ausgesetzt gewesen sind, wird bei der Suche nach den Ursachen f{\"u}r diese H{\"a}ufung von Extremereignissen auch die Frage nach der Verantwortung des Menschen hierf{\"u}r diskutiert. Gew{\"a}sserausbau, Fl{\"a}chenversiegelung, intensive landwirtschaftliche Bodenbearbeitung, Flurbereinigung und Waldsch{\"a}den sind nur einige Beispiele und Folgen der anthropogenen Eingriffe in die Landschaft. Aufgrund der Vielfalt der beteiligten Prozesse und deren Wechselwirkungen gibt es allerdings bislang nur Sch{\"a}tzungen dar{\"u}ber, wie sehr sich die Hochwassersituation hierdurch ver{\"a}ndert hat. Vorrangiges Ziel dieser Arbeit ist es, mit Hilfe eines hydrologischen Modells systematisch darzustellen, in welcher Weise, in welcher Gr{\"o}ßenordnung und unter welchen Umst{\"a}nden die Art der Landnutzung auf die Hochwasserentstehung Einfluss nimmt. Dies wird anhand exemplarischer Modellanwendungen in der hydrologischen Mesoskala untersucht. Zu diesem Zweck wurde das deterministische und fl{\"a}chendifferenzierte hydrologische Modell wasim-eth ausgew{\"a}hlt, das sich durch eine ausgewogene Mischung aus physikalisch begr{\"u}ndeten und konzeptionellen Ans{\"a}tzen auszeichnet. Das Modell wurde im Rahmen dieser Arbeit um verschiedene Aspekte erweitert, die f{\"u}r die Charakterisierung des Einflusses der Landnutzung auf die Hochwasserentstehung wichtig sind: (1) Bevorzugtes Fließen in Makroporen wird durch eine Zweiteilung des Bodens in Makroporen und Bodenmatrix dargestellt, die schnelle Infiltration und Perkolation jenseits der hydraulischen Leitf{\"a}higkeit der Bodenmatrix erm{\"o}glicht. (2) Verschl{\"a}mmung {\"a}ußert sich im Modell abh{\"a}ngig von Niederschlagsintensit{\"a}t und Vegetationsbedeckungsgrad als Verschlechterung der Infiltrationsbedingungen an der Bodenoberfl{\"a}che. (3) Das heterogene Erscheinungsbild bebauter Fl{\"a}chen mit einer Mischung aus versiegelten Bereichen und Freifl{\"a}chen wird ber{\"u}cksichtigt, indem jede Teilfl{\"a}che je nach Versiegelungsgrad in einen unversiegelten Bereich und einen versiegelten Bereich mit Anschluss an die Kanalisation aufgeteilt wird. (4) Dezentraler R{\"u}ckhalt von Niederschlagswasser kann sowohl f{\"u}r nat{\"u}rliche Mulden als auch f{\"u}r gezielt angelegte Versickerungsmulden mit definierten Infiltrationsbedingungen simuliert werden. Das erweiterte Modell wird exemplarisch auf drei mesoskalige Teileinzugsgebiete des Rheins angewandt. Diese drei Gebiete mit einer Fl{\"a}che von zwischen 100 und 500 km² wurden im Hinblick darauf ausgew{\"a}hlt, dass jeweils eine der drei Hauptlandnutzungskategorien Bebauung, landwirtschaftliche Nutzung oder Wald dominiert. F{\"u}r die drei Untersuchungsgebiete sind r{\"a}umlich explizite Landnutzungs- und Landbedeckungsszenarien entworfen worden, deren Einfluss auf die Hochwasserentstehung mit Hilfe des erweiterten hydrologischen Modells simuliert wird. Im Einzelnen werden die Auswirkungen von Verst{\"a}dterung, Maßnahmen zur Niederschlagsversickerung in Siedlungsgebieten, Stilllegung agrarisch genutzter Fl{\"a}chen, ver{\"a}nderter landwirtschaftlicher Bodenbearbeitung, Aufforstung sowie von Sturmsch{\"a}den in W{\"a}ldern untersucht. Diese Eingriffe beeinflussen die Interzeption von Niederschlag, dessen Infiltration, die oberfl{\"a}chennahen unterirdischen Fließprozesse sowie, zum Beispiel im Fall der Kanalisation, auch die Abflusskonzentration. Die hydrologischen Simulationen demonstrieren, dass die Versiegelung einer Fl{\"a}che den massivsten Eingriff in die nat{\"u}rlichen Verh{\"a}ltnisse darstellt und deshalb die st{\"a}rksten (negativen) Ver{\"a}nderungen der Hochwassersituation hervorbringt. Außerdem wird deutlich, dass eine bloße {\"A}nderung des Interzeptionsverm{\"o}gens zu keinen wesentlichen Ver{\"a}nderungen f{\"u}hrt, da die Speicherkapazit{\"a}t der Pflanzenoberfl{\"a}chen im Verh{\"a}ltnis zum Volumen hochwasserausl{\"o}sender Niederschl{\"a}ge eher klein ist. St{\"a}rkere Ver{\"a}nderungen ergeben sich hingegen aus einer {\"A}nderung der Infiltrationsbedingungen. Die Grenzen der entwickelten Methodik zeigen sich am deutlichsten bei der Simulation ver{\"a}nderter landwirtschaftlicher Bewirtschaftungsmethoden, deren mathematische Beschreibung und zahlenm{\"a}ßige Charakterisierung aufgrund der Komplexit{\"a}t der beteiligten Prozesse mit großen Unsicherheiten behaftet ist. Die Modellierungsergebnisse belegen dar{\"u}ber hinaus, dass pauschale Aussagen zum Einfluss der Landnutzung auf die Hochwasserentstehung aufgrund der entscheidenden Bedeutung der klimatischen und physiographischen Randbedingungen unzul{\"a}ssig sind. Zu den klimatischen Randbedingungen z{\"a}hlen sowohl Niederschlagsintensit{\"a}t und -dauer als auch die Feuchtebedingungen vor einem hochwasserausl{\"o}senden Niederschlag. Die physiographischen Randbedingungen sind von der geomorphologischen und geologischen Ausstattung des Gebiets vorgegeben. Weiterhin muss der r{\"a}umliche und zeitliche Maßstab, {\"u}ber den Aussagen getroffen werden, klar definiert sein, da sich mit steigender Einzugsgebietsgr{\"o}ße die relative Bedeutung sowohl der verschiedenen Niederschlagstypen als auch der physiographischen Eigenschaften verschiebt. Dies wird in der vorliegenden Arbeit im Gegensatz zu vielen anderen Untersuchungen konsequent ber{\"u}cksichtigt. In Abh{\"a}ngigkeit von Randbedingungen und r{\"a}umlichen Maßstab sind aufgrund der gewonnen Erkenntnisse folgende Aussagen zum Einfluss von Landnutzungs{\"a}nderungen auf die Hochwasserentstehung m{\"o}glich: (1) F{\"u}r intensive konvektive Niederschlagsereignisse mit tendenziell geringer Vorfeuchte ist der Einfluss der Landnutzung gr{\"o}ßer als f{\"u}r langanhaltende advektive Niederschl{\"a}ge geringer Intensit{\"a}t, da im ersten Fall ver{\"a}nderte Infiltrationsbedingungen st{\"a}rker zum Tragen kommen als bei kleinen Niederschlagsintensit{\"a}ten. (2) In kleinen Einzugsgebieten, wo kleinr{\"a}umige Konvektivzellen zu Hochwassern f{\"u}hren k{\"o}nnen, ist der Einfluss der Landnutzung dementsprechend gr{\"o}ßer als in großen Flussgebieten wie dem Rheingebiet, wo vor allem langanhaltende advektive Ereignisse (unter Umst{\"a}nden verbunden mit Schneeschmelze) relevant sind. (3) In Gebieten mit guten Speichereigenschaften wie m{\"a}chtigen, gut durchl{\"a}ssigen B{\"o}den und gut durchl{\"a}ssigem Gesteinsuntergrund ist der Einfluss der Landnutzung gr{\"o}ßer als in Gebieten mit geringm{\"a}chtigen B{\"o}den und geringdurchl{\"a}ssigem Festgestein. Dies ist darin begr{\"u}ndet, dass in Gebieten mit guten Speichereigenschaften bei einer Verschlechterung der Infiltrationsbedingungen mehr Speicherraum f{\"u}r Niederschlag verloren geht als in anderen Gebieten.},
  language  = {de}
}
@phdthesis{Wriedt2004,
  author    = {Wriedt, Gunter},
  title     = {Modelling of nitrogen transport and turnover during soil and groundwater passage in a small lowland catchment of Northern Germany},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001307},
  school      = {Universit{\"a}t Potsdam},
  year      = {2004},
  abstract  = {Stoffumsatzreaktionen und hydraulische Prozesse im Boden und Grundwasser k{\"o}nnen in Tieflandeinzugsgebieten zu einer Nitratretention f{\"u}hren. Die Untersuchung dieser Prozesse in Raum und Zeit kann mit Hilfe geeigneter Modelle erfolgen. Ziele dieser Arbeit sind: i) die Entwicklung eines geeigneten Modellansatzes durch Kombination von Teilmodellen zur Simulation des N-Transportes im Boden und Grundwasser von Tieflandeinzugsgebieten und ii) die Untersuchung von Wechselwirkungen zwischen Gebietseigenschaften und N-Transport unter besonderer Ber{\"u}cksichtigung der potentiellen N-Zufuhr in die Oberfl{\"a}chengew{\"a}sser. Der Modellansatz basiert auf der Kombination verschiedener Teilmodelle: das Bodenwasser- und -stickstoffmodell mRISK-N, das Grundwassermodell MODFLOW und das Stofftransportmodell RT3D. Zur Untersuchung der Wechselwirkungen mit den Gebietseigenschaften muss die Verteilung und Verf{\"u}gbarkeit von Reaktionspartnern ber{\"u}cksichtigt werden. Dazu wurde ein Reaktionsmodul entwickelt, welches chemische Prozesse im Grundwasser simuliert. Hierzu geh{\"o}ren die Mineralisation organischer Substanz durch Sauerstoff, Nitrat und Sulfat sowie die Pyritoxidation durch Sauerstoff und Nitrat. Der Modellansatz wurde in verschiedenen Einzelstudien angewandt, wobei jeweils bestimmte Teilmodelle im Vordergrund stehen. Alle Modellstudien basieren auf Daten aus dem Schaugrabeneinzugsgebiet (ca. 25 km\&\#178;), in der N{\"a}he von Osterburg(Altmark) im Norden Sachsen-Anhalts. Die folgenden Einzelstudien wurden durchgef{\"u}hrt: i) Evaluation des Bodenmodells anhand von Lysimeterdaten, ii) Modellierung eines Tracerexperimentes im Feldmaßstab als eine erste Anwendung des Reaktionsmoduls, iii) Untersuchung hydraulisch-chemischer Wechselwirkungen an einem 2D-Grundwassertransekt, iv) Fl{\"a}chenverteilte Modellierung von Grundwasserneubildung und Bodenstickstoffaustrag im Untersuchungsgebiet als Eingangsdaten f{\"u}r nachfolgende Grundwassersimulationen, und v) Untersuchung der Ausbreitung von Nitrat im Grundwasser und des Durchbruchs in die Oberfl{\"a}chengew{\"a}sser im Untersuchungsgebiet auf Basis einer 3D-Modellierung von Grundwasserstr{\"o}mung und reaktivem Stofftransport. Die Modellstudien zeigen, dass der Modellansatz geeignet ist, die Wechselwirkungen zwischen Stofftransport und \–umsatz und den hydraulisch-chemischen Gebietseigenschaften zu modellieren. Die Ausbreitung von Nitrat im Sediment wird wesentlich von der Verf{\"u}gbarkeit reaktiver Substanzen sowie der Verweilzeit im Grundwasserleiter bestimmt. Bei der Simulation des Untersuchungsgebietes wurde erst nach 70 Jahren eine der gegebenen Eintragssitutation entsprechende Nitratkonzentration im Grundwasserzustrom zum Grabensystem erreicht (konservativer Transport). Die Ber{\"u}cksichtigung von reaktivem Stofftransport f{\"u}hrt zu einer deutlichen Reduktion der Nitratkonzentrationen. Die Modellergebnisse zeigen, dass der Grundwasserzustrom die beobachtete Nitratbelastung im Grabensystem nicht erkl{\"a}ren kann, da der Großteil des Nitrates durch Denitrifikation verloren geht. Andere Quellen, wie direkte Eintr{\"a}ge oder Dr{\"a}nagenzufl{\"u}sse m{\"u}ssen ebenfalls in Betracht gezogen werden. Die Prognosef{\"a}higkeit des Modells f{\"u}r das Untersuchungsgebiet wird durch die Datenunsicherheiten und die Sch{\"a}tzung der Modellparameter eingeschr{\"a}nkt. Dennoch ist der Modellansatz eine wertvolle Hilfe bei der Identifizierung von belastungsrelevanten Teilfl{\"a}chen (Stoffquellen und -senken) sowie bei der Modellierung der Auswirkungen von Managementmaßnahmen oder Landnutzungsver{\"a}nderungen auf Grundlage von Szenario-Simulationen. Der Modellansatz unterst{\"u}tzt auch die Interpretation von Beobachtungsdaten, da so die lokalen Informationen in einen r{\"a}umlichen und zeitlichen Zusammenhang gestellt werden k{\"o}nnen.},
  language  = {en}
}
@phdthesis{Voss2005,
  author    = {Voß, Frank},
  title     = {Integrierte Modellierung von Durchflussdynamik und salinarer Stofftransportprozesse unter Ber{\"u}cksichtigung anthropogener Steuerungen am Beispiel der Unstrut},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-6403},
  school      = {Universit{\"a}t Potsdam},
  year      = {2005},
  abstract  = {Durch die Stilllegung der Kali-Gewinnung und -Produktion zwischen 1990 und 1993 sowie die begonnene Rekultivierung der Kali-R{\"u}ckstandshalden haben sich die Salzfrachteintragsbedingungen f{\"u}r die Fließgwew{\"a}sser im "S{\"u}dharz-Kalirevier" in Th{\"u}ringen zum Teil deutlich ver{\"a}ndert. Aufgrund erheblich geringerer Salzeintr{\"a}ge in die Vorfluter Wipper und Bode ist es m{\"o}glich geworden, zu einer {\"o}kologisch vertr{\"a}glichen Salzfrachtsteuerung {\"u}berzugehen. Die Komplexit{\"a}t der zugrunde liegenden Stofftransportprozesse im Einzugsgebiet der Wipper macht es jedoch unumg{\"a}nglich, den Steuerungsvorgang nicht nur durch reine Bilanzierungsvorg{\"a}nge auf der betrachteten Steuerstrecke zu erfassen (so wie bisher praktiziert), sondern auch die Abflussdynamik im Fließgew{\"a}sser und den Wasserhaushalt im Gebiet mit einzubeziehen. Die Ergebnisse dieser Arbeit dienen zum einen einer Vertiefung der Prozessverst{\"a}ndnisse und der Interaktion von Wasserhaushalt, Abflussbildung sowie Stofftransport in bergbaubeeinflussten Einzugsgebieten am Beispiel der Unstrut bzw. ihrer relevanten Nebenfl{\"u}sse. Zum anderen sollen sie zur Analyse und Bewertung eines Bewirtschaftungsplanes f{\"u}r die genannten Fließgew{\"a}sser herangezogen werden k{\"o}nnen. Ziel dieser Arbeit ist die Erstellung eines prognosetauglichen Steuerungsinstrumentes, das f{\"u}r die Bewirtschaftung von Flusseinzugsgebieten unterschiedlicher Gr{\"o}ße genutzt und unter den Rahmenbedingungen der bergbaubedingten salinaren Eintr{\"a}ge effektiv zur Steuerung der anthropogenen Frachten eingesetzt werden kann. Die Quellen der anthropogen eingeleiteten Salzfracht sind vor allem die R{\"u}ckstandshalden der stillgelegten Kaliwerke. Durch Niederschl{\"a}ge entstehen salzhaltige Haldenabw{\"a}sser, die zum Teil ungesteuert {\"u}ber oberfl{\"a}chennahe Ausbreitungsvorg{\"a}nge direkt in die Vorfluter gelangen, ein anderer Teil wird {\"u}ber die Speichereinrichtungen gefasst und gezielt abgestoßen. Durch Undichtigkeiten des Laugenstapelbeckens in Wipperdorf gelangen ebenfalls ungesteuerte Frachteintr{\"a}ge in die Wipper. Ein weiterer Eintragspfad ist zudem die geogene Belastung. Mit Hilfe detaillierter Angaben zu den oben genannten Eintragspfaden konnten Modellrechnungen im Zeitraum von 1992 bis 2003 durchgef{\"u}hrt werden. Durch die Ausarbeitung eines neuartigen Steuerungskonzeptes f{\"u}r das Laugenstapelbecken Wipperdorf, war es nun m{\"o}glich, die gefasste Haldenlauge entsprechend der aktuellen Abflusssituation gezielt abstoßen zu k{\"o}nnen. Neben der modelltechnischen Erfassung der aktuellen hydrologischen Situation und der Vorgabe eines Chlorid-Konzentrationssteuerzieles f{\"u}r den Pegel Hachelbich, mussten dabei weitere Randbedingungen (Beckenkapazit{\"a}t, Beckenf{\"u}llstand, Mindestf{\"u}llstand, Kapazit{\"a}t des Ableitungskanals, usw.) ber{\"u}cksichtigt werden. Es zeigte sich, dass unter Anwendung des Steuerungskonzeptes die Schwankungsbreite der Chloridkonzentration insgesamt gesehen deutlich verringert werden konnte. Die {\"U}berschreitungsh{\"a}ufigkeiten bez{\"u}glich eines Grenzwertes von 2 g Chlorid/l am Pegel Hachelbich fielen deutlich, und auch die maximale Dauer einer solchen Periode konnte stark verk{\"u}rzt werden. Kritische Situationen bei der modelltechnischen Frachtzusteuerung traten nur dann auf, wenn Niedrigwasserverh{\"a}ltnisse durch die Simulationsberechnungen noch untersch{\"a}tzt wurden. Dies hatte deutliche {\"U}berschreitungen der Zielvorgaben f{\"u}r den Pegel Hachelbich zur Folge. Mit Hilfe des Steuerungsalgorithmus konnten desweiteren auch Szenarienberechnungen durchgef{\"u}hrt werden, um die Auswirkungen zuk{\"u}nftig zu erwartender Salzfrachten n{\"a}her spezifizieren zu k{\"o}nnen. Dabei konnte festgestellt werden, dass Abdichtungsmaßnahmen der Haldenk{\"o}rper sich direkt positiv auf die Entwicklung der Konzentration in Hachelbich auswirkten. Durch zus{\"a}tzlich durchgef{\"u}hrte Langzeitszenarien konnte dar{\"u}ber hinaus nachgewiesen werden, dass langfristig eine Grenzwertfestlegung auf 1,5 g Chlorid/l in Hachelbich m{\"o}glich ist, und die Stapelkapazit{\"a}ten dazu ausreichend bemessen sind.},
  subject      = {Hydrologie},
  language  = {de}
}
@phdthesis{Hattermann2005,
  author    = {Hattermann, Fred},
  title     = {Integrated modelling of Global Change impacts in the German Elbe River Basin},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-6052},
  school      = {Universit{\"a}t Potsdam},
  year      = {2005},
  abstract  = {The scope of this study is to investigate the environmental change in the German part of the Elbe river basin, whereby the focus is on two water related problems: having too little water and having water of poor quality. The Elbe region is representative of humid to semi-humid landscapes in central Europe, where water availability during the summer season is the limiting factor for plant growth and crop yields, especially in the loess areas, where the annual precipitation is lower than 500 mm. It is most likely that water quantity problems will accelerate in future, because both the observed and the projected climate trend show an increase in temperature and a decrease in annual precipitation, especially in the summer. Another problem is nutrient pollution of rivers and lakes. In the early 1990s, the Elbe was one of the most heavily polluted rivers in Europe. Even though nutrient emissions from point sources have notably decreased in the basin due to reduction of industrial sources and introduction of new and improved sewage treatment facilities, the diffuse sources of pollution are still not sufficiently controlled. The investigations have been done using the eco-hydrological model SWIM (Soil and Water Integrated Model), which has been embedded in a model framework of climate and agro-economic models. A global scenario of climate and agro-economic change has been regionalized to generate transient climate forcing data and land use boundary conditions for the model. The model was used to transform the climate and land use changes into altered evapotranspiration, groundwater recharge, crop yields and river discharge, and to investigate the development of water quality in the river basin. Particular emphasis was given to assessing the significance of the impacts on the hydrology, taking into account in the analysis the inherent uncertainty of the regional climate change as well as the uncertainty in the results of the model. The average trend of the regional climate change scenario indicates a decrease in mean annual precipitation up to 2055 of about 1.5 \%, but with high uncertainty (covering the range from -15.3 \% to +14.8 \%), and a less uncertain increase in temperature of approximately 1.4 K. The relatively small change in precipitation in conjunction with the change in temperature leads to severe impacts on groundwater recharge and river flow. Increasing temperature induces longer vegetation periods, and the seasonality of the flow regime changes towards longer low flow spells in summer. As a results the water availability will decrease on average of the scenario simulations by approximately 15 \%. The increase in temperatures will improve the growth conditions for temperature limited crops like maize. The uncertainty of the climate trend is particularly high in regions where the change is the highest. The simulation results for the Nuthe subbasin of the Elbe indicate that retention processes in groundwater, wetlands and riparian zones have a high potential to reduce the nitrate concentrations of rivers and lakes in the basin, because they are located at the interface between catchment area and surface water bodies, where they are controlling the diffuse nutrient inputs. The relatively high retention of nitrate in the Nuthe basin is due to the long residence time of water in the subsurface (about 40 years), with good conditions for denitrification, and due to nitrate retention and plant uptake in wetlands and riparian zones. The concluding result of the study is that the natural environment and communities in parts of Central Europe will have considerably lower water resources under scenario conditions. The water quality will improve, but due to the long residence time of water and nutrients in the subsurface, this improvement will be slower in areas where the conditions for nutrient turn-over in the subsurface are poor.},
  subject      = {Hydrologie},
  language  = {en}
}
@phdthesis{Nikkhoo2019,
  author    = {Nikkhoo, Mehdi},
  title     = {Analytical and numerical elastic dislocation models of volcano deformation processes},
  doi       = {10.25932/publishup-42972},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429720},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 175},
  year      = {2019},
  abstract  = {The advances in modern geodetic techniques such as the global navigation satellite system (GNSS) and synthetic aperture radar (SAR) provide surface deformation measurements with an unprecedented accuracy and temporal and spatial resolutions even at most remote volcanoes on Earth. Modelling of the high-quality geodetic data is crucial for understanding the underlying physics of volcano deformation processes. Among various approaches, mathematical models are the most effective for establishing a quantitative link between the surface displacements and the shape and strength of deformation sources. Advancing the geodetic data analyses and hence, the knowledge on the Earth's interior processes, demands sophisticated and efficient deformation modelling approaches. Yet the majority of these models rely on simplistic assumptions for deformation source geometries and ignore complexities such as the Earth's surface topography and interactions between multiple sources. This thesis addresses this problem in the context of analytical and numerical volcano deformation modelling. In the first part, new analytical solutions for triangular dislocations (TDs) in uniform infinite and semi-infinite elastic media have been developed. Through a comprehensive investigation, the locations and causes of artefact singularities and numerical instabilities associated with TDs have been determined and these long-standing drawbacks have been addressed thoroughly. This approach has then been extended to rectangular dislocations (RDs) with full rotational degrees of freedom. Using this solution in a configuration of three orthogonal RDs a compound dislocation model (CDM) has been developed. The CDM can represent generalized volumetric and planar deformation sources efficiently. Thus, the CDM is relevant for rapid inversions in early warning systems and can also be used for detailed deformation analyses. In order to account for complex source geometries and realistic topography in the deformation models, in this thesis the boundary element method (BEM) has been applied to the new solutions for TDs. In this scheme, complex surfaces are simulated as a continuous mesh of TDs that may possess any displacement or stress boundary conditions in the BEM calculations. In the second part of this thesis, the developed modelling techniques have been applied to five different real-world deformation scenarios. As the first and second case studies the deformation sources associated with the 2015 Calbuco eruption and 2013-2016 Copahue inflation period have been constrained by using the CDM. The highly anisotropic source geometries in these two cases highlight the importance of using generalized deformation models such as the CDM, for geodetic data inversions. The other three case studies in this thesis involve high-resolution dislocation models and BEM calculations. As the third case, the 2013 pre-explosive inflation of Volc{\´a}n de Colima has been simulated by using two ellipsoidal cavities, which locate zones of pressurization in the volcano's lava dome. The fourth case study, which serves as an example for volcanotectonics interactions, the 3-D kinematics of an active ring-fault at Tend{\"u}rek volcano has been investigated through modelling displacement time series over the 2003-2010 time period. As the fifth example, the deformation sources associated with North Korea's underground nuclear test in September 2017 have been constrained. These examples demonstrate the advancement and increasing level of complexity and the general applicability of the developed dislocation modelling techniques. This thesis establishes a unified framework for rapid and high-resolution dislocation modelling, which in addition to volcano deformations can also be applied to tectonic and humanmade deformations.},
  language  = {en}
}
@phdthesis{Sharma2024,
  author    = {Sharma, Shubham},
  title     = {Integrated approaches to earthquake forecasting},
  doi       = {10.25932/publishup-63612},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-636125},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvi, 76},
  year      = {2024},
  abstract  = {A comprehensive study on seismic hazard and earthquake triggering is crucial for effective mitigation of earthquake risks. The destructive nature of earthquakes motivates researchers to work on forecasting despite the apparent randomness of the earthquake occurrences. Understanding their underlying mechanisms and patterns is vital, given their potential for widespread devastation and loss of life. This thesis combines methodologies, including Coulomb stress calculations and aftershock analysis, to shed light on earthquake complexities, ultimately enhancing seismic hazard assessment. The Coulomb failure stress (CFS) criterion is widely used to predict the spatial distributions of aftershocks following large earthquakes. However, uncertainties associated with CFS calculations arise from non-unique slip inversions and unknown fault networks, particularly due to the choice of the assumed aftershocks (receiver) mechanisms. Recent studies have proposed alternative stress quantities and deep neural network approaches as superior to CFS with predefined receiver mechanisms. To challenge these propositions, I utilized 289 slip inversions from the SRCMOD database to calculate more realistic CFS values for a layered-half space and variable receiver mechanisms. The analysis also investigates the impact of magnitude cutoff, grid size variation, and aftershock duration on the ranking of stress metrics using receiver operating characteristic (ROC) analysis. Results reveal the performance of stress metrics significantly improves after accounting for receiver variability and for larger aftershocks and shorter time periods, without altering the relative ranking of the different stress metrics. To corroborate Coulomb stress calculations with the findings of earthquake source studies in more detail, I studied the source properties of the 2005 Kashmir earthquake and its aftershocks, aiming to unravel the seismotectonics of the NW Himalayan syntaxis. I simultaneously relocated the mainshock and its largest aftershocks using phase data, followed by a comprehensive analysis of Coulomb stress changes on the aftershock planes. By computing the Coulomb failure stress changes on the aftershock faults, I found that all large aftershocks lie in regions of positive stress change, indicating triggering by either co-seismic or post-seismic slip on the mainshock fault. Finally, I investigated the relationship between mainshock-induced stress changes and associated seismicity parameters, in particular those of the frequency-magnitude (Gutenberg-Richter) distribution and the temporal aftershock decay (Omori-Utsu law). For that purpose, I used my global data set of 127 mainshock-aftershock sequences with the calculated Coulomb Stress (ΔCFS) and the alternative receiver-independent stress metrics in the vicinity of the mainshocks and analyzed the aftershocks properties depend on the stress values. Surprisingly, the results show a clear positive correlation between the Gutenberg-Richter b-value and induced stress, contrary to expectations from laboratory experiments. This observation highlights the significance of structural heterogeneity and strength variations in seismicity patterns. Furthermore, the study demonstrates that aftershock productivity increases nonlinearly with stress, while the Omori-Utsu parameters c and p systematically decrease with increasing stress changes. These partly unexpected findings have significant implications for future estimations of aftershock hazard. The findings in this thesis provides valuable insights into earthquake triggering mechanisms by examining the relationship between stress changes and aftershock occurrence. The results contribute to improved understanding of earthquake behavior and can aid in the development of more accurate probabilistic-seismic hazard forecasts and risk reduction strategies.},
  language  = {en}
}
@phdthesis{Hannemann2016,
  author    = {Hannemann, Katrin},
  title     = {Seismological investigation of the oceanic crust und upper mantle using an ocean bottom station array in the vicinity of the Gloria fault (easter mid Atlantic)},
  school      = {Universit{\"a}t Potsdam},
  pages     = {199},
  year      = {2016},
  language  = {en}
}
@phdthesis{GomezZapata2023,
  author    = {G{\´o}mez Zapata, Juan Camilo},
  title     = {Towards unifying approaches in exposure modelling for scenario-based multi-hazard risk assessments},
  doi       = {10.25932/publishup-58614},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-586140},
  school      = {Universit{\"a}t Potsdam},
  pages     = {iii, xiii, 155},
  year      = {2023},
  abstract  = {This cumulative thesis presents a stepwise investigation of the exposure modelling process for risk assessment due to natural hazards while highlighting its, to date, not much-discussed importance and associated uncertainties. Although "exposure" refers to a very broad concept of everything (and everyone) that is susceptible to damage, in this thesis it is narrowed down to the modelling of large-area residential building stocks. Classical building exposure models for risk applications have been constructed fully relying on unverified expert elicitation over data sources (e.g., outdated census datasets), and hence have been implicitly assumed to be static in time and in space. Moreover, their spatial representation has also typically been simplified by geographically aggregating the inferred composition onto coarse administrative units whose boundaries do not always capture the spatial variability of the hazard intensities required for accurate risk assessments. These two shortcomings and the related epistemic uncertainties embedded within exposure models are tackled in the first three chapters of the thesis. The exposure composition of large-area residential building stocks is studied on the scope of scenario-based earthquake loss models. Then, the proposal of optimal spatial aggregation areas of exposure models for various hazard-related vulnerabilities is presented, focusing on ground-shaking and tsunami risks. Subsequently, once the experience is gained in the study of the composition and spatial aggregation of exposure for various hazards, this thesis moves towards a multi-hazard context while addressing cumulative damage and losses due to consecutive hazard scenarios. This is achieved by proposing a novel method to account for the pre-existing damage descriptions on building portfolios as a key input to account for scenario-based multi-risk assessment. Finally, this thesis shows how the integration of the aforementioned elements can be used in risk communication practices. This is done through a modular architecture based on the exploration of quantitative risk scenarios that are contrasted with social risk perceptions of the directly exposed communities to natural hazards. In Chapter 1, a Bayesian approach is proposed to update the prior assumptions on such composition (i.e., proportions per building typology). This is achieved by integrating high-quality real observations and then capturing the intrinsic probabilistic nature of the exposure model. Such observations are accounted as real evidence from both: field inspections (Chapter 2) and freely available data sources to update existing (but outdated) exposure models (Chapter 3). In these two chapters, earthquake scenarios with parametrised ground motion fields were transversally used to investigate the role of such epistemic uncertainties related to the exposure composition through sensitivity analyses. Parametrised scenarios of seismic ground shaking were the hazard input utilised to study the physical vulnerability of building portfolios. The second issue that was investigated, which refers to the spatial aggregation of building exposure models, was investigated within two decoupled vulnerability contexts: due to seismic ground shaking through the integration of remote sensing techniques (Chapter 3); and within a multi-hazard context by integrating the occurrence of associated tsunamis (Chapter 4). Therein, a careful selection of the spatial aggregation entities while pursuing computational efficiency and accuracy in the risk estimates due to such independent hazard scenarios (i.e., earthquake and tsunami) are discussed. Therefore, in this thesis, the physical vulnerability of large-area building portfolios due to tsunamis is considered through two main frames: considering and disregarding the interaction at the vulnerability level, through consecutive and decoupled hazard scenarios respectively, which were then contrasted. Contrary to Chapter 4, where no cumulative damages are addressed, in Chapter 5, data and approaches, which were already generated in former sections, are integrated with a novel modular method to ultimately study the likely interactions at the vulnerability level on building portfolios. This is tested by evaluating cumulative damages and losses after earthquakes with increasing magnitude followed by their respective tsunamis. Such a novel method is grounded on the possibility of re-using existing fragility models within a probabilistic framework. The same approach is followed in Chapter 6 to forecast the likely cumulative damages to be experienced by a building stock located in a volcanic multi-hazard setting (ash-fall and lahars). In that section, special focus was made on the manner the forecasted loss metrics are communicated to locally exposed communities. Co-existing quantitative scientific approaches (i.e., comprehensive exposure models; explorative risk scenarios involving single and multiple hazards) and semi-qualitative social risk perception (i.e., level of understanding that the exposed communities have about their own risk) were jointly considered. Such an integration ultimately allowed this thesis to also contribute to enhancing preparedness, science divulgation at the local level as well as technology transfer initiatives. Finally, a synthesis of this thesis along with some perspectives for improvement and future work are presented.},
  language  = {en}
}
@phdthesis{JaraMunoz2016,
  author    = {Jara Mu{\~n}oz, Julius},
  title     = {Quantifying forearc deformation patterns using coastal geomorphic markers},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-102652},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XXV, 213},
  year      = {2016},
  abstract  = {Rapidly uplifting coastlines are frequently associated with convergent tectonic boundaries, like subduction zones, which are repeatedly breached by giant megathrust earthquakes. The coastal relief along tectonically active realms is shaped by the effect of sea-level variations and heterogeneous patterns of permanent tectonic deformation, which are accumulated through several cycles of megathrust earthquakes. However, the correlation between earthquake deformation patterns and the sustained long-term segmentation of forearcs, particularly in Chile, remains poorly understood. Furthermore, the methods used to estimate permanent deformation from geomorphic markers, like marine terraces, have remained qualitative and are based on unrepeatable methods. This contrasts with the increasing resolution of digital elevation models, such as Light Detection and Ranging (LiDAR) and high-resolution bathymetric surveys. Throughout this thesis I study permanent deformation in a holistic manner: from the methods to assess deformation rates, to the processes involved in its accumulation. My research focuses particularly on two aspects: Developing methodologies to assess permanent deformation using marine terraces, and comparing permanent deformation with seismic cycle deformation patterns under different spatial scales along the M8.8 Maule earthquake (2010) rupture zone. Two methods are developed to determine deformation rates from wave-built and wave-cut terraces respectively. I selected an archetypal example of a wave-built terrace at Santa Maria Island studying its stratigraphy and recognizing sequences of reoccupation events tied with eleven radiocarbon sample ages (14C ages). I developed a method to link patterns of reoccupation with sea-level proxies by iterating relative sea level curves for a range of uplift rates. I find the best fit between relative sea-level and the stratigraphic patterns for an uplift rate of 1.5 +- 0.3 m/ka. A Graphical User Interface named TerraceM® was developed in Matlab®. This novel software tool determines shoreline angles in wave-cut terraces under different geomorphic scenarios. To validate the methods, I select test sites in areas of available high-resolution LiDAR topography along the Maule earthquake rupture zone and in California, USA. The software allows determining the 3D location of the shoreline angle, which is a proxy for the estimation of permanent deformation rates. The method is based on linear interpolations to define the paleo platform and cliff on swath profiles. The shoreline angle is then located by intersecting these interpolations. The accuracy and precision of TerraceM® was tested by comparing its results with previous assessments, and through an experiment with students in a computer lab setting at the University of Potsdam. I combined the methods developed to analyze wave-built and wave-cut terraces to assess regional patterns of permanent deformation along the (2010) Maule earthquake rupture. Wave-built terraces are tied using 12 Infra Red Stimulated luminescence ages (IRSL ages) and shoreline angles in wave-cut terraces are estimated from 170 aligned swath profiles. The comparison of coseismic slip, interseismic coupling, and permanent deformation, leads to three areas of high permanent uplift, terrace warping, and sharp fault offsets. These three areas correlate with regions of high slip and low coupling, as well as with the spatial limit of at least eight historical megathrust ruptures (M8-9.5). I propose that the zones of upwarping at Arauco and Topocalma reflect changes in frictional properties of the megathrust, which result in discrete boundaries for the propagation of mega earthquakes. To explore the application of geomorphic markers and quantitative morphology in offshore areas I performed a local study of patterns of permanent deformation inferred from hitherto unrecognized drowned shorelines at the Arauco Bay, at the southern part of the (2010) Maule earthquake rupture zone. A multidisciplinary approach, including morphometry, sedimentology, paleontology, 3D morphoscopy, and a landscape Evolution Model is used to recognize, map, and assess local rates and patterns of permanent deformation in submarine environments. Permanent deformation patterns are then reproduced using elastic models to assess deformation rates of an active submarine splay fault defined as Santa Maria Fault System. The best fit suggests a reverse structure with a slip rate of 3.7 m/ka for the last 30 ka. The register of land level changes during the earthquake cycle at Santa Maria Island suggest that most of the deformation may be accrued through splay fault reactivation during mega earthquakes, like the (2010) Maule event. Considering a recurrence time of 150 to 200 years, as determined from historical and geological observations, slip between 0.3 and 0.7 m per event would be required to account for the 3.7 m/ka millennial slip rate. However, if the SMFS slips only every ~1000 years, representing a few megathrust earthquakes, then a slip of ~3.5 m per event would be required to account for the long- term rate. Such event would be equivalent to a magnitude ~6.7 earthquake capable to generate a local tsunami. The results of this thesis provide novel and fundamental information regarding the amount of permanent deformation accrued in the crust, and the mechanisms responsible for this accumulation at millennial time-scales along the M8.8 Maule earthquake (2010) rupture zone. Furthermore, the results of this thesis highlight the application of quantitative geomorphology and the use of repeatable methods to determine permanent deformation, improve the accuracy of marine terrace assessments, and estimates of vertical deformation rates in tectonically active coastal areas. This is vital information for adequate coastal-hazard assessments and to anticipate realistic earthquake and tsunami scenarios.},
  language  = {en}
}
@phdthesis{Niemz2022,
  author    = {Niemz, Peter},
  title     = {Imaging and modeling of hydraulic fractures in crystalline rock via induced seismic activity},
  doi       = {10.25932/publishup-55659},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-556593},
  school      = {Universit{\"a}t Potsdam},
  pages     = {135},
  year      = {2022},
  abstract  = {Enhanced geothermal systems (EGS) are considered a cornerstone of future sustainable energy production. In such systems, high-pressure fluid injections break the rock to provide pathways for water to circulate in and heat up. This approach inherently induces small seismic events that, in rare cases, are felt or can even cause damage. Controlling and reducing the seismic impact of EGS is crucial for a broader public acceptance. To evaluate the applicability of hydraulic fracturing (HF) in EGS and to improve the understanding of fracturing processes and the hydromechanical relation to induced seismicity, six in-situ, meter-scale HF experiments with different injection schemes were performed under controlled conditions in crystalline rock in a depth of 410 m at the {\"A}sp{\"o} Hard Rock Laboratory (Sweden). I developed a semi-automated, full-waveform-based detection, classification, and location workflow to extract and characterize the acoustic emission (AE) activity from the continuous recordings of 11 piezoelectric AE sensors. Based on the resulting catalog of 20,000 AEs, with rupture sizes of cm to dm, I mapped and characterized the fracture growth in great detail. The injection using a novel cyclic injection scheme (HF3) had a lower seismic impact than the conventional injections. HF3 induced fewer AEs with a reduced maximum magnitude and significantly larger b-values, implying a decreased number of large events relative to the number of small ones. Furthermore, HF3 showed an increased fracture complexity with multiple fractures or a fracture network. In contrast, the conventional injections developed single, planar fracture zones (Publication 1). An independent, complementary approach based on a comparison of modeled and observed tilt exploits transient long-period signals recorded at the horizontal components of two broad-band seismometers a few tens of meters apart from the injections. It validated the efficient creation of hydraulic fractures and verified the AE-based fracture geometries. The innovative joint analysis of AEs and tilt signals revealed different phases of the fracturing process, including the (re-)opening, growth, and aftergrowth of fractures, and provided evidence for the reactivation of a preexisting fault in one of the experiments (Publication 2). A newly developed network-based waveform-similarity analysis applied to the massive AE activity supports the latter finding. To validate whether the reduction of the seismic impact as observed for the cyclic injection schemes during the {\"A}sp{\"o} mine-scale experiments is transferable to other scales, I additionally calculated energy budgets for injection experiments from previously conducted laboratory tests and from a field application. Across all three scales, the cyclic injections reduce the seismic impact, as depicted by smaller maximum magnitudes, larger b-values, and decreased injection efficiencies (Publication 3).},
  language  = {en}
}
@phdthesis{Esfahani2022,
  author    = {Esfahani, Reza Dokht Dolatabadi},
  title     = {Time-dependent monitoring of near-surface and ground motion modelling: developing new data processing approaches based on Music Information Retrieval (MIR) strategies},
  doi       = {10.25932/publishup-56767},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-567671},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiv, 107},
  year      = {2022},
  abstract  = {Seismology, like many scientific fields, e.g., music information retrieval and speech signal pro- cessing, is experiencing exponential growth in the amount of data acquired by modern seismo- logical networks. In this thesis, I take advantage of the opportunities offered by "big data" and by the methods developed in the areas of music information retrieval and machine learning to predict better the ground motion generated by earthquakes and to study the properties of the surface layers of the Earth. In order to better predict seismic ground motions, I propose two approaches based on unsupervised deep learning methods, an autoencoder network and Generative Adversarial Networks. The autoencoder technique explores a massive amount of ground motion data, evaluates the required parameters, and generates synthetic ground motion data in the Fourier amplitude spectra (FAS) domain. This method is tested on two synthetic datasets and one real dataset. The application on the real dataset shows that the substantial information contained within the FAS data can be encoded to a four to the five-dimensional manifold. Consequently, only a few independent parameters are required for efficient ground motion prediction. I also propose a method based on Conditional Generative Adversarial Networks (CGAN) for simulating ground motion records in the time-frequency and time domains. CGAN generates the time-frequency domains based on the parameters: magnitude, distance, and shear wave velocities to 30 m depth (VS30). After generating the amplitude of the time-frequency domains using the CGAN model, instead of classical conventional methods that assume the amplitude spectra with a random phase spectrum, the phase of the time-frequency domains is recovered by minimizing the observed and reconstructed spectrograms. In the second part of this dissertation, I propose two methods for the monitoring and characterization of near-surface materials and site effect analyses. I implement an autocorrelation function and an interferometry method to monitor the velocity changes of near-surface materials resulting from the Kumamoto earthquake sequence (Japan, 2016). The observed seismic velocity changes during the strong shaking are due to the non-linear response of the near-surface materials. The results show that the velocity changes lasted for about two months after the Kumamoto mainshock. Furthermore, I used the velocity changes to evaluate the in-situ strain-stress relationship. I also propose a method for assessing the site proxy "VS30" using non-invasive analysis. In the proposed method, a dispersion curve of surface waves is inverted to estimate the shear wave velocity of the subsurface. This method is based on the Dix-like linear operators, which relate the shear wave velocity to the phase velocity. The proposed method is fast, efficient, and stable. All of the methods presented in this work can be used for processing "big data" in seismology and for the analysis of weak and strong ground motion data, to predict ground shaking, and to analyze site responses by considering potential time dependencies and nonlinearities.},
  language  = {en}
}
@phdthesis{Angermann2018,
  author    = {Angermann, Lisa},
  title     = {Hillslope-stream connectivity across scales},
  doi       = {10.25932/publishup-42454},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-424542},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xix, 193},
  year      = {2018},
  abstract  = {The concept of hydrologic connectivity summarizes all flow processes that link separate regions of a landscape. As such, it is a central theme in the field of catchment hydrology, with influence on neighboring disciplines such as ecology and geomorphology. It is widely acknowledged to be an important key in understanding the response behavior of a catchment and has at the same time inspired research on internal processes over a broad range of scales. From this process-hydrological point of view, hydrological connectivity is the conceptual framework to link local observations across space and scales. This is the context in which the four studies this thesis comprises of were conducted. The focus was on structures and their spatial organization as important control on preferential subsurface flow. Each experiment covered a part of the conceptualized flow path from hillslopes to the stream: soil profile, hillslope, riparian zone, and stream. For each study site, the most characteristic structures of the investigated domain and scale, such as slope deposits and peat layers were identified based on preliminary or previous investigations or literature reviews. Additionally, further structural data was collected and topographical analyses were carried out. Flow processes were observed either based on response observations (soil moisture changes or discharge patterns) or direct measurement (advective heat transport). Based on these data, the flow-relevance of the characteristic structures was evaluated, especially with regard to hillslope to stream connectivity. Results of the four studies revealed a clear relationship between characteristic spatial structures and the hydrological behavior of the catchment. Especially the spatial distribution of structures throughout the study domain and their interconnectedness were crucial for the establishment of preferential flow paths and their relevance for large-scale processes. Plot and hillslope-scale irrigation experiments showed that the macropores of a heterogeneous, skeletal soil enabled preferential flow paths at the scale of centimeters through the otherwise unsaturated soil. These flow paths connected throughout the soil column and across the hillslope and facilitated substantial amounts of vertical and lateral flow through periglacial slope deposits. In the riparian zone of the same headwater catchment, the connectivity between hillslopes and stream was controlled by topography and the dualism between characteristic subsurface structures and the geomorphological heterogeneity of the stream channel. At the small scale (1 m to 10 m) highest gains always occurred at steps along the longitudinal streambed profile, which also controlled discharge patterns at the large scale (100 m) during base flow conditions (number of steps per section). During medium and high flow conditions, however, the impact of topography and parafluvial flow through riparian zone structures prevailed and dominated the large-scale response patterns. In the streambed of a lowland river, low permeability peat layers affected the connectivity between surface water and groundwater, but also between surface water and the hyporheic zone. The crucial factor was not the permeability of the streambed itself, but rather the spatial arrangement of flow-impeding peat layers, causing increased vertical flow through narrow "windows" in contrast to predominantly lateral flow in extended areas of high hydraulic conductivity sediments. These results show that the spatial organization of structures was an important control for hydrological processes at all scales and study areas. In a final step, the observations from different scales and catchment elements were put in relation and compared. The main focus was on the theoretical analysis of the scale hierarchies of structures and processes and the direction of causal dependencies in this context. Based on the resulting hierarchical structure, a conceptual framework was developed which is capable of representing the system's complexity while allowing for adequate simplifications. The resulting concept of the parabolic scale series is based on the insight that flow processes in the terrestrial part of the catchment (soil and hillslopes) converge. This means that small-scale processes assemble and form large-scale processes and responses. Processes in the riparian zone and the streambed, however, are not well represented by the idea of convergence. Here, the large-scale catchment signal arrives and is modified by structures in the riparian zone, stream morphology, and the small-scale interactions between surface water and groundwater. Flow paths diverge and processes can better be represented by proceeding from large scales to smaller ones. The catchment-scale representation of processes and structures is thus the conceptual link between terrestrial hillslope processes and processes in the riparian corridor.},
  language  = {en}
}
@phdthesis{Duy2023,
  author    = {Duy, Nguyen Le},
  title     = {Hydrological processes in the Vietnamese Mekong Delta},
  doi       = {10.25932/publishup-60260},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-602607},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxi, 153},
  year      = {2023},
  abstract  = {Understanding hydrological processes is of fundamental importance for the Vietnamese national food security and the livelihood of the population in the Vietnamese Mekong Delta (VMD). As a consequence of sparse data in this region, however, hydrologic processes, such as the controlling processes of precipitation, the interaction between surface and groundwater, and groundwater dynamics, have not been thoroughly studied. The lack of this knowledge may negatively impact the long-term strategic planning for sustainable groundwater resources management and may result in insufficient groundwater recharge and freshwater scarcity. It is essential to develop useful methods for a better understanding of hydrological processes in such data-sparse regions. The goal of this dissertation is to advance methodologies that can improve the understanding of fundamental hydrological processes in the VMD, based on the analyses of stable water isotopes and monitoring data. The thesis mainly focuses on the controlling processes of precipitation, the mechanism of surface-groundwater interaction, and the groundwater dynamics. These processes have not been fully addressed in the VMD so far. The thesis is based on statistical analyses of the isotopic data of Global Network of Isotopes in Precipitation (GNIP), of meteorological and hydrological data from Vietnamese agencies, and of the stable water isotopes and monitoring data collected as part of this work. First, the controlling processes of precipitation were quantified by the combination of trajectory analysis, multi-factor linear regression, and relative importance analysis (hereafter, a model-based statistical approach). The validity of this approach is confirmed by similar, but mainly qualitative results obtained in other studies. The total variation in precipitation isotopes (δ18O and δ2H) can be better explained by multiple linear regression (up to 80\%) than single-factor linear regression (30\%). The relative importance analysis indicates that atmospheric moisture regimes control precipitation isotopes rather than local climatic conditions. The most crucial factor is the upstream rainfall along the trajectories of air mass movement. However, the influences of regional and local climatic factors vary in importance over the seasons. The developed model-based statistical approach is a robust tool for the interpretation of precipitation isotopes and could also be applied to understand the controlling processes of precipitation in other regions. Second, the concept of the two-component lumped-parameter model (LPM) in conjunction with stable water isotopes was applied to examine the surface-groundwater interaction in the VMD. A calibration framework was also set up to evaluate the behaviour, parameter identifiability, and uncertainties of two-component LPMs. The modelling results provided insights on the subsurface flow conditions, the recharge contributions, and the spatial variation of groundwater transit time. The subsurface flow conditions at the study site can be best represented by the linear-piston flow distribution. The contributions of the recharge sources change with distance to the river. The mean transit time (mTT) of riverbank infiltration increases with the length of the horizontal flow path and the decreasing gradient between river and groundwater. River water infiltrates horizontally mainly via the highly permeable aquifer, resulting in short mTTs (<40 weeks) for locations close to the river (<200 m). The vertical infiltration from precipitation takes place primarily via a low-permeable overlying aquitard, resulting in considerably longer mTTs (>80 weeks). Notably, the transit time of precipitation infiltration is independent of the distance to the river. All these results are hydrologically plausible and could be quantified by the presented method for the first time. This study indicates that the highly complex mechanism of surface-groundwater interaction at riverbank infiltration systems can be conceptualized by exploiting two-component LPMs. It is illustrated that the model concept can be used as a tool to investigate the hydrological functioning of mixing processes and the flow path of multiple water components in riverbank infiltration systems. Lastly, a suite of time series analysis approaches was applied to examine the groundwater dynamics in the VMD. The assessment was focused on the time-variant trends of groundwater levels (GWLs), the groundwater memory effect (representing the time that an aquifer holds water), and the hydraulic response between surface water and multi-layer alluvial aquifers. The analysis indicates that the aquifers act as low-pass filters to reduce the high-frequency signals in the GWL variations, and limit the recharge to the deep groundwater. The groundwater abstraction has exceeded groundwater recharge between 1997 and 2017, leading to the decline of groundwater levels (0.01-0.55 m/year) in all considered aquifers in the VMD. The memory effect varies according to the geographical location, being shorter in shallow aquifers and flood-prone areas and longer in deep aquifers and coastal regions. Groundwater depth, season, and location primarily control the variation of the response time between the river and alluvial aquifers. These findings are important contributions to the hydrogeological literature of a little-known groundwater system in an alluvial setting. It is suggested that time series analysis can be used as an efficient tool to understand groundwater systems where resources are insufficient to develop a physical-based groundwater model. This doctoral thesis demonstrates that important aspects of hydrological processes can be understood by statistical analysis of stable water isotope and monitoring data. The approaches developed in this thesis can be easily transferred to regions in similar tropical environments, particularly those in alluvial settings. The results of the thesis can be used as a baseline for future isotope-based studies and contribute to the hydrogeological literature of little-known groundwater systems in the VMD.},
  language  = {en}
}
@phdthesis{Schoppa2023,
  author    = {Schoppa, Lukas},
  title     = {Dynamics in the flood vulnerability of companies},
  doi       = {10.25932/publishup-59242},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-592424},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 165},
  year      = {2023},
  abstract  = {River flooding is a constant peril for societies, causing direct economic losses in the order of \$100 billion worldwide each year. Under global change, the prolonged concentration of people and assets in floodplains is accompanied by an emerging intensification of flood extremes due to anthropogenic global warming, ultimately exacerbating flood risk in many regions of the world. Flood adaptation plays a key role in the mitigation of impacts, but poor understanding of vulnerability and its dynamics limits the validity of predominant risk assessment methods and impedes effective adaptation strategies. Therefore, this thesis investigates new methods for flood risk assessment that embrace the complexity of flood vulnerability, using the understudied commercial sector as an application example. Despite its importance for accurate risk evaluation, flood loss modeling has been based on univariable and deterministic stage-damage functions for a long time. However, such simplistic methods only insufficiently describe the large variation in damage processes, which initiated the development of multivariable and probabilistic loss estimation techniques. The first study of this thesis developed flood loss models for companies that are based on emerging statistical and machine learning approaches (i.e., random forest, Bayesian network, Bayesian regression). In a benchmarking experiment on basis of object-level loss survey data, the study showed that all proposed models reproduced the heterogeneity in damage processes and outperformed conventional stage-damage functions with respect to predictive accuracy. Another advantage of the novel methods is that they convey probabilistic information in predictions, which communicates the large remaining uncertainties transparently and, hence, supports well-informed risk assessment. Flood risk assessment combines vulnerability assessment (e.g., loss estimation) with hazard and exposure analyses. Although all of the three risk drivers interact and change over time, such dependencies and dynamics are usually not explicitly included in flood risk models. Recently, systemic risk assessment that dissolves the isolated consideration of risk drivers has gained traction, but the move to holistic risk assessment comes with limited thoroughness in terms of loss estimation and data limitations. In the second study, I augmented a socio-hydrological system dynamics model for companies in Dresden, Germany, with the multivariable Bayesian regression loss model from the first study. The additional process-detail and calibration data improved the loss estimation in the systemic risk assessment framework and contributed to more accurate and reliable simulations. The model uses Bayesian inference to quantify uncertainty and learn the model parameters from a combination of prior knowledge and diverse data. The third study demonstrates the potential of the socio-hydrological flood risk model for continuous, long-term risk assessment and management. Using hydroclimatic ad socioeconomic forcing data, I projected a wide range of possible risk trajectories until the end of the century, taking into account the adaptive behavior of companies. The study results underline the necessity of increased adaptation efforts to counteract the expected intensification of flood risk due to climate change. A sensitivity analysis of the effectiveness of different adaptation measures and strategies revealed that optimized adaptation has the potential to mitigate flood risk by up to 60\%, particularly when combining structural and non-structural measures. Additionally, the application shows that systemic risk assessment is capable of capturing adverse long-term feedbacks in the human-flood system such as the levee effect. Overall, this thesis advances the representation of vulnerability in flood risk modeling by offering modeling solutions that embrace the complexity of human-flood interactions and quantify uncertainties consistently using probabilistic modeling. The studies show how scarce information in data and previous experiments can be integrated in the inference process to provide model predictions and simulations that are reliable and rich in information. Finally, the focus on the flood vulnerability of companies provides new insights into the heterogeneous damage processes and distinct flood coping of this sector.},
  language  = {en}
}
@phdthesis{Uhlemann2013,
  author    = {Uhlemann, Steffi},
  title     = {Understanding trans-basin floods in Germany : data, information and knowledge},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68868},
  school      = {Universit{\"a}t Potsdam},
  year      = {2013},
  abstract  = {Large Central European flood events of the past have demonstrated that flooding can affect several river basins at the same time leading to catastrophic economic and humanitarian losses that can stretch emergency resources beyond planned levels of service. For Germany, the spatial coherence of flooding, the contributing processes and the role of trans-basin floods for a national risk assessment is largely unknown and analysis is limited by a lack of systematic data, information and knowledge on past events. This study investigates the frequency and intensity of trans-basin flood events in Germany. It evaluates the data and information basis on which knowledge about trans-basin floods can be generated in order to improve any future flood risk assessment. In particu-lar, the study assesses whether flood documentations and related reports can provide a valuable data source for understanding trans-basin floods. An adaptive algorithm was developed that systematically captures trans-basin floods using series of mean daily discharge at a large number of sites of even time series length (1952-2002). It identifies the simultaneous occurrence of flood peaks based on the exceedance of an initial threshold of a 10 year flood at one location and consecutively pools all causally related, spatially and temporally lagged peak recordings at the other locations. A weighted cumulative index was developed that accounts for the spatial extent and the individual flood magnitudes within an event and allows quantifying the overall event severity. The parameters of the method were tested in a sensitivity analysis. An intensive study on sources and ways of information dissemination of flood-relevant publications in Germany was conducted. Based on the method of systematic reviews a strategic search approach was developed to identify relevant documentations for each of the 40 strongest trans-basin flood events. A novel framework for assessing the quality of event specific flood reports from a user's perspective was developed and validated by independent peers. The framework was designed to be generally applicable for any natural hazard type and assesses the quality of a document addressing accessibility as well as representational, contextual, and intrinsic dimensions of quality. The analysis of time-series of mean daily discharge resulted in the identification of 80 trans-basin flood events within the period 1952-2002 in Germany. The set is dominated by events that were recorded in the hydrological winter (64\%); 36\% occurred during the summer months. The occurrence of floods is characterised by a distinct clustering in time. Dividing the study period into two sub-periods, we find an increase in the percentage of winter events from 58\% in the first to 70.5\% in the second sub-period. Accordingly, we find a significant increase in the number of extreme trans-basin floods in the second sub-period. A large body of 186 flood relevant documentations was identified. For 87.5\% of the 40 strongest trans-basin floods in Germany at least one report has been found and for the most severe floods a substantial amount of documentation could be obtained. 80\% of the material can be considered grey literature (i.e. literature not controlled by commercial publishers). The results of the quality assessment show that the majority of flood event specific reports are of a good quality, i.e. they are well enough drafted, largely accurate and objective, and contain a substantial amount of information on the sources, pathways and receptors/consequences of the floods. The inclusion of this information in the process of knowledge building for flood risk assessment is recommended. Both the results as well as the data produced in this study are openly accessible and can be used for further research. The results of this study contribute to an improved spatial risk assessment in Germany. The identified set of trans-basin floods provides the basis for an assessment of the chance that flooding occurs simultaneously at a number of sites. The information obtained from flood event documentation can usefully supplement the analysis of the processes that govern flood risk.},
  language  = {en}
}
@phdthesis{Breitenbach2009,
  author    = {Breitenbach, Sebastian Franz Martin},
  title     = {Changes in monsoonal precipitation and atmospheric circulation during the Holocene reconstructed from stalagmites from Northeastern India},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-37807},
  school      = {Universit{\"a}t Potsdam},
  year      = {2009},
  abstract  = {Recent years witnessed a vast advent of stalagmites as palaeoclimate archives. The multitude of geochemical and physical proxies and a promise of a precise and accurate age model greatly appeal to palaeoclimatologists. Although substantial progress was made in speleothem-based palaeoclimate research and despite high-resolution records from low-latitudinal regions, proving that palaeo-environmental changes can be archived on sub-annual to millennial time scales our comprehension of climate dynamics is still fragmentary. This is in particular true for the summer monsoon system on the Indian subcontinent. The Indian summer monsoon (ISM) is an integral part of the intertropical convergence zone (ITCZ). As this rainfall belt migrates northward during boreal summer, it brings monsoonal rainfall. ISM strength depends however on a variety of factors, including snow cover in Central Asia and oceanic conditions in the Indic and Pacific. Presently, many of the factors influencing the ISM are known, though their exact forcing mechanism and mutual relations remain ambiguous. Attempts to make an accurate prediction of rainfall intensity and frequency and drought recurrence, which is extremely important for South Asian countries, resemble a puzzle game; all interaction need to fall into the right place to obtain a complete picture. My thesis aims to create a faithful picture of climate change in India, covering the last 11,000 ka. NE India represents a key region for the Bay of Bengal (BoB) branch of the ISM, as it is here where the monsoon splits into a northwestward and a northeastward directed arm. The Meghalaya Plateau is the first barrier for northward moving air masses and receives excessive summer rainfall, while the winter season is very dry. The proximity of Meghalaya to the Tibetan Plateau on the one hand and the BoB on the other hand make the study area a key location for investigating the interaction between different forcings that governs the ISM. A basis for the interpretation of palaeoclimate records, and a first important outcome of my thesis is a conceptual model which explains the observed pattern of seasonal changes in stable isotopes (d18O and d2H) in rainfall. I show that although in tropical and subtropical regions the amount effect is commonly called to explain strongly depleted isotope values during enhanced rainfall, alone it cannot account for observed rainwater isotope variability in Meghalaya. Monitoring of rainwater isotopes shows no expected negative correlation between precipitation amount and d18O of rainfall. In turn I find evidence that the runoff from high elevations carries an inherited isotopic signature into the BoB, where during the ISM season the freshwater builds a strongly depleted plume on top of the marine water. The vapor originating from this plume is likely to memorize' and transmit further very negative d18O values. The lack of data does not allow for quantication of this plume effect' on isotopes in rainfall over Meghalaya but I suggest that it varies on seasonal to millennial timescales, depending on the runoff amount and source characteristics. The focal point of my thesis is the extraction of climatic signals archived in stalagmites from NE India. High uranium concentration in the stalagmites ensured excellent age control required for successful high-resolution climate reconstructions. Stable isotope (d18O and d13C) and grey-scale data allow unprecedented insights into millennial to seasonal dynamics of the summer and winter monsoon in NE India. ISM strength (i. e. rainfall amount) is recorded in changes in d18Ostalagmites. The d13C signal, reflecting drip rate changes, renders a powerful proxy for dry season conditions, and shows similarities to temperature-related changes on the Tibetan Plateau. A sub-annual grey-scale profile supports a concept of lower drip rate and slower stalagmite growth during dry conditions. During the Holocene, ISM followed a millennial-scale decrease of insolation, with decadal to centennial failures resulting from atmospheric changes. The period of maximum rainfall and enhanced seasonality corresponds to the Holocene Thermal Optimum observed in Europe. After a phase of rather stable conditions, 4.5 kyr ago, the strengthening ENSO system dominated the ISM. Strong El Nino events weakened the ISM, especially when in concert with positive Indian Ocean dipole events. The strongest droughts of the last 11 kyr are recorded during the past 2 kyr. Using the advantage of a well-dated stalagmite record at hand I tested the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to detect sub-annual to sub-decadal changes in element concentrations in stalagmites. The development of a large ablation cell allows for ablating sample slabs of up to 22 cm total length. Each analyzed element is a potential proxy for different climatic parameters. Combining my previous results with the LAICP- MS-generated data shows that element concentration depends not only on rainfall amount and associated leaching from the soil. Additional factors, like biological activity and hydrogeochemical conditions in the soil and vadose zone can eventually affect the element content in drip water and in stalagmites. I present a theoretical conceptual model for my study site to explain how climatic signals can be transmitted and archived in stalagmite carbonate. Further, I establish a first 1500 year long element record, reconstructing rainfall variability. Additionally, I hypothesize that volcanic eruptions, producing large amounts of sulfuric acid, can influence soil acidity and hence element mobilization.},
  language  = {en}
}
@phdthesis{Petrow2009,
  author    = {Petrow, Theresia},
  title     = {Floods in Germany : analyses of trends, seasonality and circulation patterns},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-37392},
  school      = {Universit{\"a}t Potsdam},
  year      = {2009},
  abstract  = {Flood hazard estimations are conducted with a variety of methods. These include flood frequency analysis (FFA), hydrologic and hydraulic modelling, probable maximum discharges as well as climate scenarios. However, most of these methods assume stationarity of the used time series, i.e., the series must not exhibit trends. Against the background of climate change and proven significant trends in atmospheric circulation patterns, it is questionable whether these changes are also reflected in the discharge data. The aim of this PhD thesis is therefore to clarify, in a spatially-explicit manner, whether the available discharge data derived from selected German catchments exhibit trends. Concerning the flood hazard, the suitability of the currently used stationary FFA approaches is evaluated for the discharge data. Moreover, dynamics in atmospheric circulation patterns are studied and the link between trends in these patterns and discharges is investigated. To tackle this research topic, a number of different analyses are conducted. The first part of the PhD thesis comprises the study and trend test of 145 discharge series from catchments, which cover most of Germany for the period 1951-2002. The seasonality and trend pattern of eight flood indicators, such as maximum series and peak-over-threshold series, are analyzed in a spatially-explicit manner. Analyses are performed on different spatial scales: at the local scale, through gauge-specific analyses, and on the catchment-wide and basin scales. Besides the analysis of discharge series, data on atmospheric circulation patterns (CP) are an important source of information, upon which conclusions about the flood hazard can be drawn. The analyses of these circulation patterns (after Hess und Brezowsky) and the study of the link to peak discharges form the second part of the thesis. For this, daily data on the dominant CP across Europe are studied; these are represented by different indicators, which are tested for trend. Moreover, analyses are performed to extract flood triggering circulation patterns and to estimate the flood potential of CPs. Correlations between discharge series and CP indicators are calculated to assess a possible link between them. For this research topic, data from 122 meso-scale catchments in the period 1951-2002 are used. In a third part, the Mulde catchment, a mesoscale sub-catchment of the Elbe basin, is studied in more detail. Fifteen discharge series of different lengths in the period 1910-2002 are available for the seasonally differentiated analysis of the flood potential of CPs and flood influencing landscape parameters. For trend tests of discharge and CP data, different methods are used. The Mann-Kendall test is applied with a significance level of 10\%, ensuring statistically sound results. Besides the test of the entire series for trend, multiple time-varying trend tests are performed with the help of a resampling approach in order to better differentiate short-term fluctuations from long-lasting trends. Calculations of the field significance complement the flood hazard assessment for the studied regions. The present thesis shows that the flood hazard is indeed significantly increasing for selected regions in Germany during the winter season. Especially affected are the middle mountain ranges in Central Germany. This increase of the flood hazard is attributed to a longer persistence of selected CPs during winter. Increasing trends in summer floods are found in the Rhine and Danube catchments, decreasing trends in the Elbe and Weser catchments. Finally, a significant trend towards a reduced diversity of CPs is found causing fewer patterns with longer persistence to dominate the weather over Europe. The detailed study of the Mulde catchment reveals a flood regime with frequent low winter floods and fewer summer floods, which bear, however, the potential of becoming extreme. Based on the results, the use of instationary approaches for flood hazard estimation is recommended in order to account for the detected trends in many of the series. Through this methodology it is possible to directly consider temporal changes in flood series, which in turn reduces the possibility of large under- or overestimations of the extreme discharges, respectively.},
  language  = {en}
}
@phdthesis{Falter2016,
  author    = {Falter, Daniela},
  title     = {A novel approach for large-scale flood risk assessments},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-90239},
  school      = {Universit{\"a}t Potsdam},
  pages     = {95},
  year      = {2016},
  abstract  = {In the past, floods were basically managed by flood control mechanisms. The focus was set on the reduction of flood hazard. The potential consequences were of minor interest. Nowadays river flooding is increasingly seen from the risk perspective, including possible consequences. Moreover, the large-scale picture of flood risk became increasingly important for disaster management planning, national risk developments and the (re-) insurance industry. Therefore, it is widely accepted that risk-orientated flood management ap-proaches at the basin-scale are needed. However, large-scale flood risk assessment methods for areas of several 10,000 km² are still in early stages. Traditional flood risk assessments are performed reach wise, assuming constant probabilities for the entire reach or basin. This might be helpful on a local basis, but where large-scale patterns are important this approach is of limited use. Assuming a T-year flood (e.g. 100 years) for the entire river network is unrealistic and would lead to an overestimation of flood risk at the large scale. Due to the lack of damage data, additionally, the probability of peak discharge or rainfall is usually used as proxy for damage probability to derive flood risk. With a continuous and long term simulation of the entire flood risk chain, the spatial variability of probabilities could be consider and flood risk could be directly derived from damage data in a consistent way. The objective of this study is the development and application of a full flood risk chain, appropriate for the large scale and based on long term and continuous simulation. The novel approach of 'derived flood risk based on continuous simulations' is introduced, where the synthetic discharge time series is used as input into flood impact models and flood risk is directly derived from the resulting synthetic damage time series. The bottleneck at this scale is the hydrodynamic simu-lation. To find suitable hydrodynamic approaches for the large-scale a benchmark study with simplified 2D hydrodynamic models was performed. A raster-based approach with inertia formulation and a relatively high resolution of 100 m in combination with a fast 1D channel routing model was chosen. To investigate the suitability of the continuous simulation of a full flood risk chain for the large scale, all model parts were integrated into a new framework, the Regional Flood Model (RFM). RFM consists of the hydrological model SWIM, a 1D hydrodynamic river network model, a 2D raster based inundation model and the flood loss model FELMOps+r. Subsequently, the model chain was applied to the Elbe catchment, one of the largest catchments in Germany. For the proof-of-concept, a continuous simulation was per-formed for the period of 1990-2003. Results were evaluated / validated as far as possible with available observed data in this period. Although each model part introduced its own uncertainties, results and runtime were generally found to be adequate for the purpose of continuous simulation at the large catchment scale. Finally, RFM was applied to a meso-scale catchment in the east of Germany to firstly perform a flood risk assessment with the novel approach of 'derived flood risk assessment based on continuous simulations'. Therefore, RFM was driven by long term synthetic meteorological input data generated by a weather generator. Thereby, a virtual time series of climate data of 100 x 100 years was generated and served as input to RFM providing subsequent 100 x 100 years of spatially consistent river discharge series, inundation patterns and damage values. On this basis, flood risk curves and expected annual damage could be derived directly from damage data, providing a large-scale picture of flood risk. In contrast to traditional flood risk analysis, where homogenous return periods are assumed for the entire basin, the presented approach provides a coherent large-scale picture of flood risk. The spatial variability of occurrence probability is respected. Additionally, data and methods are consistent. Catchment and floodplain processes are repre-sented in a holistic way. Antecedent catchment conditions are implicitly taken into account, as well as physical processes like storage effects, flood attenuation or channel-floodplain interactions and related damage influencing effects. Finally, the simulation of a virtual period of 100 x 100 years and consequently large data set on flood loss events enabled the calculation of flood risk directly from damage distributions. Problems associated with the transfer of probabilities in rainfall or peak runoff to probabilities in damage, as often used in traditional approaches, are bypassed. RFM and the 'derived flood risk approach based on continuous simulations' has the potential to provide flood risk statements for national planning, re-insurance aspects or other questions where spatially consistent, large-scale assessments are required.},
  language  = {en}
}
@phdthesis{Guse2010,
  author    = {Guse, Bj{\"o}rn Felix},
  title     = {Improving flood frequency analysis by integration of empirical and probabilistic regional envelope curves},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-49265},
  school      = {Universit{\"a}t Potsdam},
  year      = {2010},
  abstract  = {Flood design necessitates discharge estimates for large recurrence intervals. However, in a flood frequency analysis, the uncertainty of discharge estimates increases with higher recurrence intervals, particularly due to the small number of available flood data. Furthermore, traditional distribution functions increase unlimitedly without consideration of an upper bound discharge. Hence, additional information needs to be considered which is representative for high recurrence intervals. Envelope curves which bound the maximum observed discharges of a region are an adequate regionalisation method to provide additional spatial information for the upper tail of a distribution function. Probabilistic regional envelope curves (PRECs) are an extension of the traditional empirical envelope curve approach, in which a recurrence interval is estimated for a regional envelope curve (REC). The REC is constructed for a homogeneous pooling group of sites. The estimation of this recurrence interval is based on the effective sample years of data considering the intersite dependence among all sites of the pooling group. The core idea of this thesis was an improvement of discharge estimates for high recurrence intervals by integrating empirical and probabilistic regional envelope curves into the flood frequency analysis. Therefore, the method of probabilistic regional envelope curves was investigated in detail. Several pooling groups were derived by modifying candidate sets of catchment descriptors and settings of two different pooling methods. These were used to construct PRECs. A sensitivity analysis shows the variability of discharges and the recurrence intervals for a given site due to the different assumptions. The unit flood of record which governs the intercept of PREC was determined as the most influential aspect. By separating the catchments into nested and unnested pairs, the calculation algorithm for the effective sample years of data was refined. In this way, the estimation of the recurrence intervals was improved, and therefore the use of different parameter sets for nested and unnested pairs of catchments is recommended. In the second part of this thesis, PRECs were introduced into a distribution function. Whereas in the traditional approach only discharge values are used, PRECs provide a discharge and its corresponding recurrence interval. Hence, a novel approach was developed, which allows a combination of the PREC results with the traditional systematic flood series while taking the PREC recurrence interval into consideration. An adequate mixed bounded distribution function was presented, which in addition to the PREC results also uses an upper bound discharge derived by an empirical envelope curve. By doing so, two types of additional information which are representative for the upper tail of a distribution function were included in the flood frequency analysis. The integration of both types of additional information leads to an improved discharge estimation for recurrence intervals between 100 and 1000 years.},
  language  = {en}
}
@phdthesis{Vorogushyn2008,
  author    = {Vorogushyn, Sergiy},
  title     = {Analysis of flood hazard under consideration of dike breaches},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27646},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {River reaches protected by dikes exhibit high damage potential due to strong value accumulation in the hinterland areas. While providing an efficient protection against low magnitude flood events, dikes may fail under the load of extreme water levels and long flood durations. Hazard and risk assessments for river reaches protected by dikes have not adequately considered the fluvial inundation processes up to now. Particularly, the processes of dike failures and their influence on the hinterland inundation and flood wave propagation lack comprehensive consideration. This study focuses on the development and application of a new modelling system which allows a comprehensive flood hazard assessment along diked river reaches under consideration of dike failures. The proposed Inundation Hazard Assessment Model (IHAM) represents a hybrid probabilistic-deterministic model. It comprises three models interactively coupled at runtime. These are: (1) 1D unsteady hydrodynamic model of river channel and floodplain flow between dikes, (2) probabilistic dike breach model which determines possible dike breach locations, breach widths and breach outflow discharges, and (3) 2D raster-based diffusion wave storage cell model of the hinterland areas behind the dikes. Due to the unsteady nature of the 1D and 2D coupled models, the dependence between hydraulic load at various locations along the reach is explicitly considered. The probabilistic dike breach model describes dike failures due to three failure mechanisms: overtopping, piping and slope instability caused by the seepage flow through the dike core (micro-instability). The 2D storage cell model driven by the breach outflow boundary conditions computes an extended spectrum of flood intensity indicators such as water depth, flow velocity, impulse, inundation duration and rate of water rise. IHAM is embedded in a Monte Carlo simulation in order to account for the natural variability of the flood generation processes reflected in the form of input hydrographs and for the randomness of dike failures given by breach locations, times and widths. The model was developed and tested on a ca. 91 km heavily diked river reach on the German part of the Elbe River between gauges Torgau and Vockerode. The reach is characterised by low slope and fairly flat extended hinterland areas. The scenario calculations for the developed synthetic input hydrographs for the main river and tributary were carried out for floods with return periods of T = 100, 200, 500, 1000 a. Based on the modelling results, probabilistic dike hazard maps could be generated that indicate the failure probability of each discretised dike section for every scenario magnitude. In the disaggregated display mode, the dike hazard maps indicate the failure probabilities for each considered breach mechanism. Besides the binary inundation patterns that indicate the probability of raster cells being inundated, IHAM generates probabilistic flood hazard maps. These maps display spatial patterns of the considered flood intensity indicators and their associated return periods. Finally, scenarios of polder deployment for the extreme floods with T = 200, 500, 1000 were simulated with IHAM. The developed IHAM simulation system represents a new scientific tool for studying fluvial inundation dynamics under extreme conditions incorporating effects of technical flood protection measures. With its major outputs in form of novel probabilistic inundation and dike hazard maps, the IHAM system has a high practical value for decision support in flood management.},
  language  = {en}
}
@phdthesis{Nguyen2014,
  author    = {Nguyen, Van Manh},
  title     = {Large-scale floodplain sediment dynamics in the Mekong Delta : present state and future prospects},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-72512},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 95},
  year      = {2014},
  abstract  = {The Mekong Delta (MD) sustains the livelihood and food security of millions of people in Vietnam and Cambodia. It is known as the "rice bowl" of South East Asia and has one of the world's most productive fisheries. Sediment dynamics play a major role for the high productivity of agriculture and fishery in the delta. However, the MD is threatened by climate change, sea level rise and unsustainable development activities in the Mekong Basin. But despite its importance and the expected threats, the understanding of the present and future sediment dynamics in the MD is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains and the scarcity of observations. Thus this thesis aimed at (1) the quantification of suspended sediment dynamics and associated sediment-nutrient deposition in floodplains of the MD, and (2) assessed the impacts of likely future boundary changes on the sediment dynamics in the MD. The applied methodology combines field experiments and numerical simulation to quantify and predict the sediment dynamics in the entire delta in a spatially explicit manner. The experimental part consists of a comprehensive procedure to monitor quantity and spatial variability of sediment and associated nutrient deposition for large and complex river floodplains, including an uncertainty analysis. The measurement campaign applied 450 sediment mat traps in 19 floodplains over the MD for a complete flood season. The data also supports quantification of nutrient deposition in floodplains based on laboratory analysis of nutrient fractions of trapped sedimentation.The main findings are that the distribution of grain size and nutrient fractions of suspended sediment are homogeneous over the Vietnamese floodplains. But the sediment deposition within and between ring dike floodplains shows very high spatial variability due to a high level of human inference. The experimental findings provide the essential data for setting up and calibration of a large-scale sediment transport model for the MD. For the simulation studies a large scale hydrodynamic model was developed in order to quantify large-scale floodplain sediment dynamics. The complex river-channel-floodplain system of the MD is described by a quasi-2D model linking a hydrodynamic and a cohesive sediment transport model. The floodplains are described as quasi-2D presentations linked to rivers and channels modeled in 1D by using control structures. The model setup, based on the experimental findings, ignored erosion and re-suspension processes due to a very high degree of human interference during the flood season. A two-stage calibration with six objective functions was developed in order to calibrate both the hydrodynamic and sediment transport modules. The objective functions include hydraulic and sediment transport parameters in main rivers, channels and floodplains. The model results show, for the first time, the tempo-spatial distribution of sediment and associated nutrient deposition rates in the whole MD. The patterns of sediment transport and deposition are quantified for different sub-systems. The main factors influencing spatial sediment dynamics are the network of rivers, channels and dike-rings, sluice gate operations, magnitude of the floods and tidal influences. The superposition of these factors leads to high spatial variability of the sediment transport and deposition, in particular in the Vietnamese floodplains. Depending on the flood magnitude, annual sediment loads reaching the coast vary from 48\% to 60\% of the sediment load at Kratie, the upper boundary of the MD. Deposited sediment varies from 19\% to 23\% of the annual load at Kratie in Cambodian floodplains, and from 1\% to 6\% in the compartmented and diked floodplains in Vietnam. Annual deposited nutrients (N, P, K), which are associated to the sediment deposition, provide on average more than 50\% of mineral fertilizers typically applied for rice crops in non-flooded ring dike compartments in Vietnam. This large-scale quantification provides a basis for estimating the benefits of the annual Mekong floods for agriculture and fishery, for assessing the impacts of future changes on the delta system, and further studies on coastal deposition/erosion. For the estimation of future prospects a sensitivity-based approach is applied to assess the response of floodplain hydraulics and sediment dynamics to the changes in the delta boundaries including hydropower development, climate change in the Mekong River Basin and effective sea level rise. The developed sediment model is used to simulate the mean sediment transport and sediment deposition in the whole delta system for the baseline (2000-2010) and future (2050-2060) periods. For each driver we derive a plausible range of future changes and discretize it into five levels, resulting in altogether 216 possible factor combinations. Our results thus cover all plausible future pathways of sediment dynamics in the delta based on current knowledge. The uncertainty of the range of the resulting impacts can be decreased in case more information on these drivers becomes available. Our results indicate that the hydropower development dominates the changes in sediment dynamics of the Mekong Delta, while sea level rise has the smallest effect. The floodplains of Vietnamese Mekong Delta are much more sensitive to the changes compared to the other subsystems of the delta. In terms of median changes of the three combined drivers, the inundation extent is predicted to increase slightly, but the overall floodplain sedimentation would be reduced by approximately 40\%, while the sediment load to the Sea would diminish to half of the current rates. These findings provide new and valuable information on the possible impacts of future development on the delta, and indicate the most vulnerable areas. Thus, the presented results are a significant contribution to the ongoing international discussion on the hydropower development in the Mekong basin and its impact on the Mekong delta.},
  language  = {en}
}
@phdthesis{Laudan2019,
  author    = {Laudan, Jonas},
  title     = {Changing susceptibility of flood-prone residents in Germany},
  doi       = {10.25932/publishup-43442},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434421},
  school      = {Universit{\"a}t Potsdam},
  pages     = {113},
  year      = {2019},
  abstract  = {Floods are among the most costly natural hazards that affect Europe and Germany, demanding a continuous adaptation of flood risk management. While social and economic development in recent years altered the flood risk patterns mainly with regard to an increase in flood exposure, different flood events are further expected to increase in frequency and severity in certain European regions due to climate change. As a result of recent major flood events in Germany, the German flood risk management shifted to more integrated approaches that include private precaution and preparation to reduce the damage on exposed assets. Yet, detailed insights into the preparedness decisions of flood-prone households remain scarce, especially in connection to mental impacts and individual coping strategies after being affected by different flood types. This thesis aims to gain insights into flash floods as a costly hazard in certain German regions and compares the damage driving factors to the damage driving factors of river floods. Furthermore, psychological impacts as well as the effects on coping and mitigation behaviour of flood-affected households are assessed. In this context, psychological models such as the Protection Motivation Theory (PMT) and methods such as regressions and Bayesian statistics are used to evaluate influencing factors on the mental coping after an event and to identify psychological variables that are connected to intended private flood mitigation. The database consists of surveys that were conducted among affected households after major river floods in 2013 and flash floods in 2016. The main conclusions that can be drawn from this thesis reveal that the damage patterns and damage driving factors of strong flash floods differ significantly from those of river floods due to a rapid flow origination process, higher flow velocities and flow forces. However, the effects on mental coping of people that have been affected by flood events appear to be weakly influenced by different flood types, but yet show a coherence to the event severity, where often thinking of the respective event is pronounced and also connected to a higher mitigation motivation. The mental coping and preparation after floods is further influenced by a good information provision and a social environment, which encourages a positive attitude towards private mitigation. As an overall recommendation, approaches for an integrated flood risk management in Germany should be followed that also take flash floods into account and consider psychological characteristics of affected households to support and promote private flood mitigation. Targeted information campaigns that concern coping options and discuss current flood risks are important to better prepare for future flood hazards in Germany.},
  language  = {en}
}
@phdthesis{Nied2016,
  author    = {Nied, Manuela},
  title     = {The role of soil moisture and weather patterns for flood occurrence and characteristics at the river basin scale},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94612},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XVI, 86},
  year      = {2016},
  abstract  = {Flood generation at the scale of large river basins is triggered by the interaction of the hydrological pre-conditions and the meteorological event conditions at different spatial and temporal scales. This interaction controls diverse flood generating processes and results in floods varying in magnitude and extent, duration as well as socio-economic consequences. For a process-based understanding of the underlying cause-effect relationships, systematic approaches are required. These approaches have to cover the complete causal flood chain, including the flood triggering meteorological event in combination with the hydrological (pre-)conditions in the catchment, runoff generation, flood routing, possible floodplain inundation and finally flood losses. In this thesis, a comprehensive probabilistic process-based understanding of the causes and effects of floods is advanced. The spatial and temporal dynamics of flood events as well as the geophysical processes involved in the causal flood chain are revealed and the systematic interconnections within the flood chain are deciphered by means of the classification of their associated causes and effects. This is achieved by investigating the role of the hydrological pre-conditions and the meteorological event conditions with respect to flood occurrence, flood processes and flood characteristics as well as their interconnections at the river basin scale. Broadening the knowledge about flood triggers, which up to now has been limited to linking large-scale meteorological conditions to flood occurrence, the influence of large-scale pre-event hydrological conditions on flood initiation is investigated. Using the Elbe River basin as an example, a classification of soil moisture, a key variable of pre-event conditions, is developed and a probabilistic link between patterns of soil moisture and flood occurrence is established. The soil moisture classification is applied to continuously simulated soil moisture data which is generated using the semi-distributed conceptual rainfall-runoff model SWIM. Applying successively a principal component analysis and a cluster analysis, days of similar soil moisture patterns are identified in the period November 1951 to October 2003. The investigation of flood triggers is complemented by including meteorological conditions described by a common weather pattern classification that represents the main modes of atmospheric state variability. The newly developed soil moisture classification thereby provides the basis to study the combined impact of hydrological pre-conditions and large-scale meteorological event conditions on flood occurrence at the river basin scale. A process-based understanding of flood generation and its associated probabilities is attained by classifying observed flood events into process-based flood types such as snowmelt floods or long-rain floods. Subsequently, the flood types are linked to the soil moisture and weather patterns. Further understanding of the processes is gained by modeling of the complete causal flood chain, incorporating a rainfall-runoff model, a 1D/2D hydrodynamic model and a flood loss model. A reshuffling approach based on weather patterns and the month of their occurrence is developed to generate synthetic data fields of meteorological conditions, which drive the model chain, in order to increase the flood sample size. From the large number of simulated flood events, the impact of hydro-meteorological conditions on various flood characteristics is detected through the analysis of conditional cumulative distribution functions and regression trees. The results show the existence of catchment-scale soil moisture patterns, which comprise of large-scale seasonal wetting and drying components as well as of smaller-scale variations related to spatially heterogeneous catchment processes. Soil moisture patterns frequently occurring before the onset of floods are identified. In winter, floods are initiated by catchment-wide high soil moisture, whereas in summer the flood-initiating soil moisture patterns are diverse and the soil moisture conditions are less stable in time. The combined study of both soil moisture and weather patterns shows that the flood favoring hydro-meteorological patterns as well as their interactions vary seasonally. In the analysis period, 18 \% of the weather patterns only result in a flood in the case of preceding soil saturation. The classification of 82 past events into flood types reveals seasonally varying flood processes that can be linked to hydro-meteorological patterns. For instance, the highest flood potential for long-rain floods is associated with a weather pattern that is often detected in the presence of so-called 'Vb' cyclones. Rain-on-snow and snowmelt floods are associated with westerly and north-westerly wind directions. The flood characteristics vary among the flood types and can be reproduced by the applied model chain. In total, 5970 events are simulated. They reproduce the observed event characteristics between September 1957 and August 2002 and provide information on flood losses. A regression tree analysis relates the flood processes of the simulated events to the hydro-meteorological (pre-)event conditions and highlights the fact that flood magnitude is primarily controlled by the meteorological event, whereas flood extent is primarily controlled by the soil moisture conditions. Describing flood occurrence, processes and characteristics as a function of hydro-meteorological patterns, this thesis is part of a paradigm shift towards a process-based understanding of floods. The results highlight that soil moisture patterns as well as weather patterns are not only beneficial to a probabilistic conception of flood initiation but also provide information on the involved flood processes and the resulting flood characteristics.},
  language  = {en}
}
@phdthesis{Sieg2018,
  author    = {Sieg, Tobias},
  title     = {Reliability of flood damage estimations across spatial scales},
  doi       = {10.25932/publishup-42616},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426161},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIII, 115},
  year      = {2018},
  abstract  = {Extreme Naturereignisse sind ein integraler Bestandteil der Natur der Erde. Sie werden erst dann zu Gefahren f{\"u}r die Gesellschaft, wenn sie diesen Ereignissen ausgesetzt ist. Dann allerdings k{\"o}nnen Naturgefahren verheerende Folgen f{\"u}r die Gesellschaft haben. Besonders hydro-meteorologische Gefahren wie zum Beispiel Flusshochwasser, Starkregenereignisse, Winterst{\"u}rme, Orkane oder Tornados haben ein hohes Schadenspotential und treten rund um den Globus auf. Einhergehend mit einer immer w{\"a}rmer werdenden Welt, werden auch Extremwetterereignisse, welche potentiell Naturgefahren ausl{\"o}sen k{\"o}nnen, immer wahrscheinlicher. Allerdings tr{\"a}gt nicht nur eine sich ver{\"a}ndernde Umwelt zur Erh{\"o}hung des Risikos von Naturgefahren bei, sondern auch eine sich ver{\"a}ndernde Gesellschaft. Daher ist ein angemessenes Risikomanagement erforderlich um die Gesellschaft auf jeder r{\"a}umlichen Ebene an diese Ver{\"a}nderungen anzupassen. Ein essentieller Bestandteil dieses Managements ist die Absch{\"a}tzung der {\"o}konomischen Auswirkungen der Naturgefahren. Bisher allerdings fehlen verl{\"a}ssliche Methoden um die Auswirkungen von hydro-meteorologischen Gefahren abzusch{\"a}tzen. Ein Hauptbestandteil dieser Arbeit ist daher die Entwicklung und Anwendung einer neuen Methode, welche die Verl{\"a}sslichkeit der Schadenssch{\"a}tzung verbessert. Die Methode wurde beispielhaft zur Sch{\"a}tzung der {\"o}konomischen Auswirkungen eines Flusshochwassers auf einzelne Unternehmen bis hin zu den Auswirkungen auf das gesamte Wirtschaftssystem Deutschlands erfolgreich angewendet. Bestehende Methoden geben meist wenig Information {\"u}ber die Verl{\"a}sslichkeit ihrer Sch{\"a}tzungen. Da diese Informationen Entscheidungen zur Anpassung an das Risiko erleichtern, wird die Verl{\"a}sslichkeit der Schadenssch{\"a}tzungen mit der neuen Methode dargestellt. Die Verl{\"a}sslichkeit bezieht sich dabei nicht nur auf die Schadenssch{\"a}tzung selber, sondern auch auf die Annahmen, die {\"u}ber betroffene Geb{\"a}ude gemacht werden. Nach diesem Prinzip kann auch die Verl{\"a}sslichkeit von Annahmen {\"u}ber die Zukunft dargestellt werden, dies ist ein wesentlicher Aspekt f{\"u}r Prognosen. Die Darstellung der Verl{\"a}sslichkeit und die erfolgreiche Anwendung zeigt das Potential der Methode zur Verwendung von Analysen f{\"u}r gegenw{\"a}rtige und zuk{\"u}nftige hydro-meteorologische Gefahren.},
  language  = {en}
}
@phdthesis{Murawski2017,
  author    = {Murawski, Aline},
  title     = {Trends in precipitation over Germany and the Rhine basin related to changes in weather patterns},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-412725},
  school      = {Universit{\"a}t Potsdam},
  pages     = {112},
  year      = {2017},
  abstract  = {Niederschlag als eine der wichtigsten meteorologischen Gr{\"o}ßen f{\"u}r Landwirtschaft, Wasserversorgung und menschliches Wohlbefinden hat schon immer erh{\"o}hte Aufmerksamkeit erfahren. Niederschlagsmangel kann verheerende Auswirkungen haben, wie z.B. Missernten und Wasserknappheit. {\"U}berm{\"a}ßige Niederschl{\"a}ge andererseits bergen jedoch ebenfalls Gefahren in Form von Hochwasser oder Sturzfluten und wiederum Missernten. Daher wurde viel Arbeit in die Detektion von Niederschlags{\"a}nderungen und deren zugrundeliegende Prozesse gesteckt. Insbesondere angesichts von Klimawandel und unter Ber{\"u}cksichtigung des Zusammenhangs zwischen Temperatur und atmosph{\"a}rischer Wasserhaltekapazit{\"a}t, ist großer Bedarf an Forschung zum Verst{\"a}ndnis der Auswirkungen von Klimawandel auf Niederschlags{\"a}nderungen gegeben. Die vorliegende Arbeit hat das Ziel, vergangene Ver{\"a}nderungen in Niederschlag und anderen meteorologischen Variablen zu verstehen. F{\"u}r verschiedene Zeitr{\"a}ume wurden Tendenzen gefunden und mit entsprechenden Ver{\"a}nderungen in der großskaligen atmosph{\"a}rischen Zirkulation in Zusammenhang gebracht. Die Ergebnisse dieser Arbeit k{\"o}nnen als Grundlage f{\"u}r die Attributierung von Hochwasserver{\"a}nderungen zu Klimawandel genutzt werden. Die Annahmen f{\"u}r die Maßstabsverkleinerung („Downscaling") der Daten von großskaligen Zirkulationsmodellen auf die lokale Skala wurden hier getestet und verifziert. In einem ersten Schritt wurden Niederschlagsver{\"a}nderungen in Deutschland analysiert. Dabei lag der Fokus nicht nur auf Niederschlagssummen, sondern auch auf Eigenschaften der statistischen Verteilung, {\"U}bergangswahrscheinlichkeiten als Maß f{\"u}r Trocken- und Niederschlagsperioden und Extremniederschlagsereignissen. Den r{\"a}umlichen Fokus auf das Rheineinzugsgebiet, das gr{\"o}ßte Flusseinzugsgebiet Deutschlands und einer der Hauptwasserwege Europas, verlagernd, wurden nachgewiesene Ver{\"a}nderungen in Niederschlag und anderen meteorologischen Gr{\"o}ßen in Bezug zu einer „optimierten" Wetterlagenklassifikation analysiert. Die Wetterlagenklassifikation wurde unter der Maßgabe entwickelt, die Varianz des lokalen Klimas bestm{\"o}glich zu erkl{\"a}ren. Die letzte hier behandelte Frage dreht sich darum, ob die beobachteten Ver{\"a}nderungen im lokalen Klima eher H{\"a}ufigkeits{\"a}nderungen der Wetterlagen zuzuordnen sind oder einer Ver{\"a}nderung der Wetterlagen selbst. Eine gebr{\"a}uchliche Annahme f{\"u}r einen Downscaling-Ansatz mit Hilfe von Wetterlagen und einem stochastischen Wettergenerator ist, dass Klimawandel sich allein durch eine Ver{\"a}nderung der H{\"a}ufigkeit von Wetterlagen ausdr{\"u}ckt, die Eigenschaften der Wetterlagen dabei jedoch konstant bleiben. Diese Annahme wurde {\"u}berpr{\"u}ft und die F{\"a}higkeit der neuesten Generation von Zirkulationsmodellen, diese Wetterlagen zu reproduzieren, getestet. Niederschlagsver{\"a}nderungen in Deutschland im Zeitraum 1951-2006 lassen sich zusammenfassen als negativ im Sommer und positiv in allen anderen Jahreszeiten. Verschiedene Niederschlagscharakteristika best{\"a}tigen die Tendenz in den Niederschlagssummen: w{\"a}hrend mittlere und extreme Niederschlagstageswerte im Winter zugenommen haben, sind auch zusammenh{\"a}ngende Niederschlagsperioden l{\"a}nger geworden (ausgedr{\"u}ckt als eine gestiegene Wahrscheinlichkeit f{\"u}r einen Tag mit Niederschlag gefolgt von einem weiteren nassen Tag). Im Sommer wurde das Gegenteil beobachtet: gesunkene Niederschlagssummen, untermauert von verringerten Mittel- und Extremwerten und l{\"a}ngeren Trockenperioden. Abseits dieser allgemeinen Zusammenfassung f{\"u}r das gesamte Gebiet Deutschlands, ist die r{\"a}umliche Verteilung von Niederschlagsver{\"a}nderungen deutlich heterogener. Vermehrter Niederschlag im Winter wurde haupts{\"a}chlich im Nordwesten und S{\"u}dosten Deutschlands beobachtet, w{\"a}hrend im Fr{\"u}hling die st{\"a}rksten Ver{\"a}nderungen im Westen und im Herbst im S{\"u}den aufgetreten sind. Das saisonale Bild wiederum l{\"o}st sich f{\"u}r die zugeh{\"o}rigen Monate auf, z.B. setzt sich der Anstieg im Herbstniederschlag aus deutlich vermehrtem Niederschlag im S{\"u}dwesten im Oktober und im S{\"u}dosten im November zusammen. Diese Ergebnisse betonen die starken r{\"a}umlichen Zusammenh{\"a}nge der Niederschlags{\"a}nderungen. Der n{\"a}chste Schritt hinsichtlich einer Zuordnung von Niederschlagsver{\"a}nderungen zu {\"A}nderungen in großskaligen Zirkulationsmustern, war die Ableitung einer Wetterlagenklassifikation, die die betrachteten lokalen Klimavariablen hinreichend stratifizieren kann. Fokussierend auf Temperatur, Globalstrahlung und Luftfeuchte zus{\"a}tzlich zu Niederschlag, wurde eine Klassifikation basierend auf Luftdruck, Temperatur und spezifischer Luftfeuchtigkeit als am besten geeignet erachtet, die Varianz der lokalen Variablen zu erkl{\"a}ren. Eine vergleichsweise hohe Anzahl von 40 Wetterlagen wurde ausgew{\"a}hlt, die es erlaubt, typische Druckmuster durch die zus{\"a}tzlich verwendete Temperaturinformation einzelnen Jahreszeiten zuzuordnen. W{\"a}hrend die F{\"a}higkeit, Varianz im Niederschlag zu erkl{\"a}ren, relativ gering ist, ist diese deutlich besser f{\"u}r Globalstrahlung und nat{\"u}rlich Temperatur. Die meisten der aktuellen Zirkulationsmodelle des CMIP5-Ensembles sind in der Lage, die Wetterlagen hinsichtlich H{\"a}ufigkeit, Saisonalit{\"a}t und Persistenz hinreichend gut zu reproduzieren. Schließlich wurden dieWetterlagen bez{\"u}glich Ver{\"a}nderungen in ihrer H{\"a}ufigkeit, Saisonalit{\"a}t und Persistenz, sowie der Wetterlagen-spezifischen Niederschl{\"a}ge und Temperatur, untersucht. Um Unsicherheiten durch die Wahl eines bestimmten Analysezeitraums auszuschließen, wurden alle m{\"o}glichen Zeitr{\"a}ume mit mindestens 31 Jahren im Zeitraum 1901-2010 untersucht. Dadurch konnte die Annahme eines konstanten Zusammenhangs zwischen Wetterlagen und lokalem Wetter gr{\"u}ndlich {\"u}berpr{\"u}ft werden. Es wurde herausgefunden, dass diese Annahme nur zum Teil haltbar ist. W{\"a}hrend Ver{\"a}nderungen in der Temperatur haupts{\"a}chlich auf Ver{\"a}nderungen in der Wetterlagenh{\"a}ufigkeit zur{\"u}ckzuf{\"u}hren sind, wurde f{\"u}r Niederschlag ein erheblicher Teil von Ver{\"a}nderungen innerhalb einzelner Wetterlagen gefunden. Das Ausmaß und sogar das Vorzeichen der Ver{\"a}nderungen h{\"a}ngt hochgradig vom untersuchten Zeitraum ab. Die H{\"a}ufigkeit einiger Wetterlagen steht in direkter Beziehung zur langfristigen Variabilit{\"a}t großskaliger Zirkulationsmuster. Niederschlagsver{\"a}nderungen variieren nicht nur r{\"a}umlich, sondern auch zeitlich - Aussagen {\"u}ber Tendenzen sind nur in Bezug zum jeweils untersuchten Zeitraum g{\"u}ltig. W{\"a}hrend ein Teil der Ver{\"a}nderungen auf {\"A}nderungen der großskaligen Zirkulation zur{\"u}ckzuf{\"u}hren ist, gibt es auch deutliche Ver{\"a}nderungen innerhalb einzelner Wetterlagen. Die Ergebnisse betonen die Notwendigkeit f{\"u}r einen sorgf{\"a}ltigen Nachweis von Ver{\"a}nderungen m{\"o}glichst verschiedene Zeitr{\"a}ume zu untersuchen und mahnen zur Vorsicht bei der Anwendung von Downscaling-Ans{\"a}tzen mit Hilfe von Wetterlagen, da diese die Auswirkungen von Klimaver{\"a}nderungen durch das Vernachl{\"a}ssigen von Wetterlagen-internen Ver{\"a}nderungen falsch einsch{\"a}tzen k{\"o}nnten.},
  language  = {en}
}
@phdthesis{Molkenthin2016,
  author    = {Molkenthin, Christian},
  title     = {Sensitivity analysis in seismic Hazard assessment using algorithmic differentiation},
  school      = {Universit{\"a}t Potsdam},
  pages     = {114},
  year      = {2016},
  language  = {en}
}
@phdthesis{Wang2011,
  author    = {Wang, Yongbo},
  title     = {Late glacial to Holocene climate and vegetation changes on the Tibetan Plateau inferred from fossil pollen records in lacustrine sediments},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-63155},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {The past climate in central Asia, and especially on the Tibetan Plateau (TP), is of great importance for an understanding of global climate processes and for predicting the future climate. As a major influence on the climate in this region, the Asian Summer Monsoon (ASM) and its evolutionary history are of vital importance for accurate predictions. However, neither the evolutionary pattern of the summer monsoon nor the driving mechanisms behind it are yet clearly understood. For this research, I first synthesized previously published Late Glacial to Holocene climatic records from monsoonal central Asia in order to extract the general climate signals and the associated summer monsoon intensities. New climate and vegetation sequences were then established using improved quantitative methods, focusing on fossil pollen records recovered from Tibetan lakes and also incorporating new modern datasets. The pollen-vegetation and vegetation-climate relationships on the TP were also evaluated in order to achieve a better understanding of fossil pollen records. The synthesis of previously published moisture-related palaeoclimate records in monsoonal central Asia revealed generally different temporal patterns for the two monsoonal subsystems, i.e. the Indian Summer Monsoon (ISM) and East Asian Summer Monsoon (EASM). The ISM appears to have experienced maximum wet conditions during the early Holocene, while many records from the area affected by the EASM indicate relatively dry conditions at that time, particularly in north-central China where the maximum moisture levels occurred during the middle Holocene. A detailed consideration of possible driving factors affecting the summer monsoon, including summer solar insolation and sea surface temperatures, revealed that the ISM was primarily driven by variations in northern hemisphere solar insolation, and that the EASM may have been constrained by the ISM resulting in asynchronous patterns of evolution for these two subsystems. This hypothesis is further supported by modern monsoon indices estimated using the NCEP/NCAR Reanalysis data from the last 50 years, which indicate a significant negative correlation between the two summer monsoon subsystems. By analogy with the early Holocene, intensification of the ISM during coming decades could lead to increased aridification elsewhere as a result of the asynchronous nature of the monsoon subsystems, as can already be observed in the meteorological data from the last 15 years. A quantitative climate reconstruction using fossil pollen records was achieved through analysis of sediment core recovered from Lake Donggi Cona (in the north-eastern part of the TP) which has been dated back to the Last Glacial Maximum (LGM). A new data-set of modern pollen collected from large lakes in arid to semi-arid regions of central Asia is also presented herein. The concept of "pollen source area" was introduced to modern climate calibration based on pollen from large lakes, and was applied to the fossil pollen sequence from Lake Donggi Cona. Extremely dry conditions were found to have dominated the LGM, and a subsequent gradually increasing trend in moisture during the Late Glacial period was terminated by an abrupt reversion to a dry phase that lasted for about 1000 years and coincided with the first Heinrich Event of the northern Atlantic region. Subsequent periods corresponding to the warm B{\o}lling-Aller{\o}d period and the Younger Dryas cold event were followed by moist conditions during the early Holocene, with annual precipitation of up to about 400 mm. A slightly drier trend after 9 cal ka BP was then followed by a second wet phase during the middle Holocene that lasted until 4.5 cal ka BP. Relatively steady conditions with only slight fluctuations then dominated the late Holocene, resulting in the present climatic conditions. In order to investigate the relationship between vegetation and climate, temporal variations in the possible driving factors for vegetation change on the northern TP were examined using a high resolution late Holocene pollen record from Lake Kusai. Moving-window Redundancy Analyses (RDAs) were used to evaluate the correlations between pollen assemblages and individual sedimentary proxies. These analyses have revealed frequent fluctuations in the relative abundances of alpine steppe and alpine desert components, and in particular a decrease in the total vegetation cover at around 1500 cal a BP. The climate was found to have had an important influence on vegetation changes when conditions were relatively wet and stable. However, after the 1500 cal a BP threshold in vegetation cover was crossed the vegetation appears to have been affected more by extreme events such as dust storms or fluvial erosion than by the general climatic trends. In addition, pollen spectra over the last 600 years have been revealed by Procrustes analysis to be significantly different from those recovered from older samples, which is attributed to an increased human impact that resulted in unprecedented changes to the composition of the vegetation. Theoretical models that have been developed and widely applied to the European area (i.e. the Extended R-Value (ERV) model and the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model) have been applied to the high alpine TP ecosystems in order to investigate the pollen-vegetation relationships, as well as for quantitative reconstructions of vegetation abundance. The modern pollen-vegetation relationships for four common pollen species on the TP have been investigated using Poaceae as the reference taxa. The ERV Submodel 2 yielded relatively high PPEs for the steppe and desert taxa (Artemisia Chenopodiaceae), and low PPEs for the Cyperaceae that are characteristic of the alpine Kobresia meadows. The plant abundances on the central and north-eastern TP were quantified by applying these PPEs to four post-Late Glacial fossil pollen sequences. The reconstructed vegetation assemblages for the four pollen sequences always yielded smaller compositional species turnovers than suggested by the pollen spectra, indicating that the strength of the previously-reported vegetation changes may therefore have been overestimated. In summary, the key findings of this thesis are that (a) the two ASM subsystems show asynchronous patterns during both the Holocene and modern time periods, (b) fossil pollen records from large lakes reflect regional signals for which the pollen source areas need to be taken into account, (c) climate is not always the main driver for vegetation change, and (d) previously reported vegetation changes on the TP may have been overestimated because they ignored inter-species variations in pollen productivity.},
  language  = {en}
}
@phdthesis{Heim2005,
  author    = {Heim, Birgit},
  title     = {Qualitative and quantitative analyses of Lake Baikal's surface-waters using ocean colour satellite data (SeaWiFS)},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7182},
  school      = {Universit{\"a}t Potsdam},
  year      = {2005},
  abstract  = {One of the most difficult issues when dealing with optical water remote-sensing is its acceptance as a useful application for environmental research. This problem is, on the one hand, concerned with the optical complexity and variability of the investigated natural media, and therefore the question arises as to the plausibility of the parameters derived from remote-sensing techniques. Detailed knowledge about the regional bio- and chemico-optical properties is required for such studies, however such information is seldom available for the sites of interest. On the other hand, the primary advantage of remote-sensing information, which is the provision of a spatial overview, may not be exploited fully by the disciplines that would benefit most from such information. It is often seen in a variety of disciplines that scientists have been primarily trained to look at discrete data sets, and therefore have no experience of incorporating information dealing with spatial heterogeneity. In this thesis, the opportunity was made available to assess the potential of Ocean Colour data to provide spatial and seasonal information about the surface waters of Lake Baikal (Siberia). While discrete limnological field data is available, the spatial extension of Lake Baikal is enormous (ca. 600 km), while the field data are limited to selected sites and expedition time windows. Therefore, this remote-sensing investigation aimed to support a multi-disciplinary limnological investigation within the framework of the paleoclimate EU-project 'High Resolution CONTINENTal Paleoclimate Record in Lake Baikal, Siberia (CONTINENT)' using spatial and seasonal information from the SeaWiFS satellite (NASA). From this, the SeaWiFS study evolved to become the first efficient bio-optical satellite study of Lake Baikal. During the course of three years, field work including spectral field measurements and water sampling, was carried out at Lake Baikal in Southern Siberia, and at the Mecklenburg and Brandenburg lake districts in Germany. The first step in processing the SeaWiFS satellite data involved adapting the SeaDAS (NASA) atmospheric-correction processing to match as close as possible the specific conditions of Lake Baikal. Next, various Chl-a algorithms were tested on the atmospherically-corrected optimized SeaWiFS data set (years 2001 to 2002), comparing the CONTINENT pigment ground-truth data with the Chl-a concentrations derived from the satellite data. This showed the high performance of the global Chl-a products OC2 and OC4 for the oligotrophic, transparent waters (bio-optical Case 1) of Lake Baikal. However, considerable Chl-a overestimation prevailed in bio-optical Case 2 areas for the case of discharge events. High-organic terrigenous input into Lake Baikal could be traced and information extracted using the SeaWiFS spectral data. Suspended Particulate Matter (SPM) was quantified by the regression of the SeaDAS attenuation coefficient as the optical parameter with SPM field data. Finally, the Chl-a and terrigenous input maps derived from the remote sensing data were used to assist with analyzing the relationships between the various discrete data obtained during the CONTINENT field work. Hence, plausible spatial and seasonal information describing autochthonous and allochthonous material in Lake Baikal could be provided by satellite data.Lake Baikal, with its bio-optical complexity and its different areas of Case 1 and Case 2 waters, is a very interesting case study for Ocean Colour analyses. Proposals for future Ocean Colour studies of Lake Baikal are discussed, including which bio-optical parameters for analytical models still need to be clarified by field investigations.},
  subject      = {Baikalsee},
  language  = {en}
}
@phdthesis{Wischnewski2011,
  author    = {Wischnewski, Juliane},
  title     = {Reconstructing climate variability on the Tibetan Plateau : comparing aquatic and terrestrial signals},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-52453},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Spatial and temporal temperature and moisture patterns across the Tibetan Plateau are very complex. The onset and magnitude of the Holocene climate optimum in the Asian monsoon realm, in particular, is a subject of considerable debate as this time period is often used as an analogue for recent global warming. In the light of contradictory inferences regarding past climate and environmental change on the Tibetan Plateau, I have attempted to explain mismatches in the timing and magnitude of change. Therefore, I analysed the temporal variation of fossil pollen and diatom spectra and the geochemical record from palaeo-ecological records covering different time scales (late Quaternary and the last 200 years) from two core regions in the NE and SE Tibetan Plateau. For interpretation purposes I combined my data with other available palaeo-ecological data to set up corresponding aquatic and terrestrial proxy data sets of two lake pairs and two sets of sites. I focused on the direct comparison of proxies representing lacustrine response to climate signals (e.g., diatoms, ostracods, geochemical record) and proxies representing changes in the terrestrial environment (i.e., terrestrial pollen), in order to asses whether the lake and its catchments respond at similar times and magnitudes to environmental changes. Therefore, I introduced the established numerical technique procrustes rotation as a new approach in palaeoecology to quantitatively compare raw data of any two sedimentary records of interest in order to assess their degree of concordance. Focusing on the late Quaternary, sediment cores from two lakes (Kuhai Lake 35.3°N; 99.2°E; 4150 m asl; and Koucha Lake 34.0°N; 97.2°E; 4540 m asl) on the semi-arid northeastern Tibetan Plateau were analysed to identify post-glacial vegetation and environmental changes, and to investigate the responses of lake ecosystems to such changes. Based on the pollen record, five major vegetation and climate changes could be identified: (1) A shift from alpine desert to alpine steppe indicates a change from cold, dry conditions to warmer and more moist conditions at 14.8 cal. ka BP, (2) alpine steppe with tundra elements points to conditions of higher effective moisture and a stepwise warming climate at 13.6 cal. ka BP, (3) the appearance of high-alpine meadow vegetation indicates a further change towards increased moisture, but with colder temperatures, at 7.0 cal. ka BP, (4) the reoccurrence of alpine steppe with desert elements suggests a return to a significantly colder and drier phase at 6.3 cal. ka BP, and (5) the establishment of alpine steppe-meadow vegetation indicates a change back to relatively moist conditions at 2.2 cal. ka BP. To place the reconstructed climate inferences from the NE Tibetan Plateau into the context of Holocene moisture evolution across the Tibetan Plateau, I applied a five-scale moisture index and average link clustering to all available continuous pollen and non-pollen palaeoclimate records from the Tibetan Plateau, in an attempt to detect coherent regional and temporal patterns of moisture evolution on the Plateau. However, no common temporal or spatial pattern of moisture evolution during the Holocene could be detected, which can be assigned to the complex responses of different proxies to environmental changes in an already very heterogeneous mountain landscape, where minor differences in elevation can result in marked variations in microenvironments. Focusing on the past 200 years, I analysed the sedimentary records (LC6 Lake 29.5°N, 94.3°E, 4132 m asl; and Wuxu Lake 29.9°N, 101.1°E, 3705 m asl) from the southeastern Tibetan Plateau. I found that despite presumed significant temperature increases over that period, pollen and diatom records from the SE Tibetan Plateau reveal only very subtle changes throughout their profiles. The compositional species turnover investigated over the last 200 years appears relatively low in comparison to the species reorganisations during the Holocene. The results indicate that climatically induced ecological thresholds are not yet crossed, but that human activity has an increasing influence, particularly on the terrestrial ecosystem. Forest clearances and reforestation have not caused forest decline in our study area, but a conversion of natural forests to semi-natural secondary forests. The results from the numerical proxy comparison of the two sets of two pairs of Tibetan lakes indicate that the use of different proxies and the work with palaeo-ecological records from different lake types can cause deviant stories of inferred change. Irrespective of the timescale (Holocene or last 200 years) or region (SE or NE Tibetan Plateau) analysed, the agreement in terms of the direction, timing, and magnitude of change between the corresponding terrestrial data sets is generally better than the match between the corresponding lacustrine data sets, suggesting that lacustrine proxies may partly be influenced by in-lake or local catchment processes whereas the terrestrial proxy reflects a more regional climatic signal. The current disaccord on coherent temporal and spatial climate patterns on the Tibetan Plateau can partly be ascribed to the complexity of proxy response and lake systems on the Tibetan Plateau. Therefore, a multi-proxy, multi-site approach is important in order to gain a reliable climate interpretation for the complex mountain landscape of the Tibetan Plateau.},
  language  = {en}
}
@phdthesis{Aichner2009,
  author    = {Aichner, Bernhard},
  title     = {Aquatic macrophyte-derived biomarkers as palaeolimnological proxies on the Tibetan Plateau},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42095},
  school      = {Universit{\"a}t Potsdam},
  year      = {2009},
  abstract  = {The Tibetan Plateau is the largest elevated landmass in the world and profoundly influences atmospheric circulation patterns such as the Asian monsoon system. Therefore this area has been increasingly in focus of palaeoenvironmental studies. This thesis evaluates the applicability of organic biomarkers for palaeolimnological purposes on the Tibetan Plateau with a focus on aquatic macrophyte-derived biomarkers. Submerged aquatic macrophytes have to be considered to significantly influence the sediment organic matter due to their high abundance in many Tibetan lakes. They can show highly 13C-enriched biomass because of their carbon metabolism and it is therefore crucial for the interpretation of δ13C values in sediment cores to understand to which extent aquatic macrophytes contribute to the isotopic signal of the sediments in Tibetan lakes and in which way variations can be explained in a palaeolimnological context. Additionally, the high abundance of macrophytes makes them interesting as potential recorders of lake water δD. Hydrogen isotope analysis of biomarkers is a rapidly evolving field to reconstruct past hydrological conditions and therefore of special relevance on the Tibetan Plateau due to the direct linkage between variations of monsoon intensity and changes in regional precipitation / evaporation balances. A set of surface sediment and aquatic macrophyte samples from the central and eastern Tibetan Plateau was analysed for composition as well as carbon and hydrogen isotopes of n-alkanes. It was shown how variable δ13C values of bulk organic matter and leaf lipids can be in submerged macrophytes even of a single species and how strongly these parameters are affected by them in corresponding sediments. The estimated contribution of the macrophytes by means of a binary isotopic model was calculated to be up to 60\% (mean: 40\%) to total organic carbon and up to 100\% (mean: 66\%) to mid-chain n-alkanes. Hydrogen isotopes of n-alkanes turned out to record δD of meteoric water of the summer precipitation. The apparent enrichment factor between water and n-alkanes was in range of previously reported ones (≈-130 per mille) at the most humid sites, but smaller (average: -86 per mille) at sites with a negative moisture budget. This indicates an influence of evaporation and evapotranspiration on δD of source water for aquatic and terrestrial plants. The offset between δD of mid- and long-chain n-alkanes was close to zero in most of the samples, suggesting that lake water as well as soil and leaf water are affected to a similar extent by those effects. To apply biomarkers in a palaeolimnological context, the aliphatic biomarker fraction of a sediment core from Lake Koucha (34.0° N; 97.2° E; eastern Tibetan Plateau) was analysed for concentrations, δ13C and δD values of compounds. Before ca. 8 cal ka BP, the lake was dominated by aquatic macrophyte-derived mid-chain n-alkanes, while after 6 cal ka BP high concentrations of a C20 highly branched isoprenoid compound indicate a predominance of phytoplankton. Those two principally different states of the lake were linked by a transition period with high abundances of microbial biomarkers. δ13C values were relatively constant for long-chain n-alkanes, while mid-chain n-alkanes showed variations between -23.5 to -12.6 per mille. Highest values were observed for the assumed period of maximum macrophyte growth during the late glacial and for the phytoplankton maximum during the middle and late Holocene. Therefore, the enriched values were interpreted to be caused by carbon limitation which in turn was induced by high macrophyte and primary productivity, respectively. Hydrogen isotope signatures of mid-chain n-alkanes have been shown to be able to track a previously deduced episode of reduced moisture availability between ca. 10 and 7 cal ka BP, indicated by a 20 per mille shift towards higher δD values. Indications for cooler episodes at 6.0, 3.1 and 1.8 cal ka BP were gained from drops of biomarker concentrations, especially microbial-derived hopanoids, and from coincidental shifts towards lower δ13C values. Those episodes correspond well with cool events reported from other locations on the Tibetan Plateau as well as in the Northern Hemisphere. To conclude, the study of recent sediments and plants improved the understanding of factors affecting the composition and isotopic signatures of aliphatic biomarkers in sediments. Concentrations and isotopic signatures of the biomarkers in Lake Koucha could be interpreted in a palaeolimnological context and contribute to the knowledge about the history of the lake. Aquatic macrophyte-derived mid-chain n-alkanes were especially useful, due to their high abundance in many Tibetan Lakes and their ability to record major changes of lake productivity and palaeo-hydrological conditions. Therefore, they have the potential to contribute to a fuller understanding of past climate variability in this key region for atmospheric circulation systems.},
  language  = {en}
}
@phdthesis{TabaresJimenez2021,
  author    = {Tabares Jimenez, Ximena del Carmen},
  title     = {A palaeoecological approach to savanna dynamics and shrub encroachment in Namibia},
  doi       = {10.25932/publishup-49281},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-492815},
  school      = {Universit{\"a}t Potsdam},
  pages     = {121},
  year      = {2021},
  abstract  = {The spread of shrubs in Namibian savannas raises questions about the resilience of these ecosystems to global change. This makes it necessary to understand the past dynamics of the vegetation, since there is no consensus on whether shrub encroachment is a new phenomenon, nor on its main drivers. However, a lack of long-term vegetation datasets for the region and the scarcity of suitable palaeoecological archives, makes reconstructing past vegetation and land cover of the savannas a challenge. To help meet this challenge, this study addresses three main research questions: 1) is pollen analysis a suitable tool to reflect the vegetation change associated with shrub encroachment in savanna environments? 2) Does the current encroached landscape correspond to an alternative stable state of savanna vegetation? 3) To what extent do pollen-based quantitative vegetation reconstructions reflect changes in past land cover? The research focuses on north-central Namibia, where despite being the region most affected by shrub invasion, particularly since the 21st century, little is known about the dynamics of this phenomenon. Field-based vegetation data were compared with modern pollen data to assess their correspondence in terms of composition and diversity along precipitation and grazing intensity gradients. In addition, two sediment cores from Lake Otjikoto were analysed to reveal changes in vegetation composition that have occurred in the region over the past 170 years and their possible drivers. For this, a multiproxy approach (fossil pollen, sedimentary ancient DNA (sedaDNA), biomarkers, compound specific carbon (δ13C) and deuterium (δD) isotopes, bulk carbon isotopes (δ13Corg), grain size, geochemical properties) was applied at high taxonomic and temporal resolution. REVEALS modelling of the fossil pollen record from Lake Otjikoto was run to quantitatively reconstruct past vegetation cover. For this, we first made pollen productivity estimates (PPE) of the most relevant savanna taxa in the region using the extended R-value model and two pollen dispersal options (Gaussian plume model and Lagrangian stochastic model). The REVEALS-based vegetation reconstruction was then validated using remote sensing-based regional vegetation data. The results show that modern pollen reflects the composition of the vegetation well, but diversity less well. Interestingly, precipitation and grazing explain a significant amount of the compositional change in the pollen and vegetation spectra. The multiproxy record shows that a state change from open Combretum woodland to encroached Terminalia shrubland can occur over a century, and that the transition between states spans around 80 years and is characterized by a unique vegetation composition. This transition is supported by gradual environmental changes induced by management (i.e. broad-scale logging for the mining industry, selective grazing and reduced fire activity associated with intensified farming) and related land-use change. Derived environmental changes (i.e. reduced soil moisture, reduced grass cover, changes in species composition and competitiveness, reduced fire intensity) may have affected the resilience of Combretum open woodlands, making them more susceptible to change to an encroached state by stochastic events such as consecutive years of precipitation and drought, and by high concentrations of pCO2. We assume that the resulting encroached state was further stabilized by feedback mechanisms that favour the establishment and competitiveness of woody vegetation. The REVEALS-based quantitative estimates of plant taxa indicate the predominance of a semi-open landscape throughout the 20th century and a reduction in grass cover below 50\% since the 21st century associated with the spread of encroacher woody taxa. Cover estimates show a close match with regional vegetation data, providing support for the vegetation dynamics inferred from multiproxy analyses. Reasonable PPEs were made for all woody taxa, but not for Poaceae. In conclusion, pollen analysis is a suitable tool to reconstruct past vegetation dynamics in savannas. However, because pollen cannot identify grasses beyond family level, a multiproxy approach, particularly the use of sedaDNA, is required. I was able to separate stable encroached states from mere woodland phases, and could identify drivers and speculate about related feedbacks. In addition, the REVEALS-based quantitative vegetation reconstruction clearly reflects the magnitude of the changes in the vegetation cover that occurred during the last 130 years, despite the limitations of some PPEs. This research provides new insights into pollen-vegetation relationships in savannas and highlights the importance of multiproxy approaches when reconstructing past vegetation dynamics in semi-arid environments. It also provides the first time series with sufficient taxonomic resolution to show changes in vegetation composition during shrub encroachment, as well as the first quantitative reconstruction of past land cover in the region. These results help to identify the different stages in savanna dynamics and can be used to calibrate predictive models of vegetation change, which are highly relevant to land management.},
  language  = {en}
}
@phdthesis{Heinecke2018,
  author    = {Heinecke, Liv},
  title     = {Environmental change in the Eastern Pamir Mountains during last 28 cal ka BP},
  school      = {Universit{\"a}t Potsdam},
  pages     = {139},
  year      = {2018},
  language  = {en}
}
@phdthesis{Niemeyer2016,
  author    = {Niemeyer, Bastian},
  title     = {Vegetation reconstruction and assessment of plant diversity at the treeline ecotone in northern Siberia},
  school      = {Universit{\"a}t Potsdam},
  pages     = {146},
  year      = {2016},
  language  = {en}
}
@phdthesis{Wieczorek2017,
  author    = {Wieczorek, Mareike},
  title     = {Stand structure patterns in the Siberian treeline under climate change},
  school      = {Universit{\"a}t Potsdam},
  pages     = {140},
  year      = {2017},
  language  = {en}
}
@phdthesis{Kemper2023,
  author    = {Kemper, Tarek},
  title     = {KLIMAGRAR - Neue Methoden der Begleitforschung am Beispiel des klimagerechten Handelns in der Landwirtschaft},
  doi       = {10.25932/publishup-60192},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-601924},
  school      = {Universit{\"a}t Potsdam},
  pages     = {109},
  year      = {2023},
  abstract  = {In Forschungsprogrammen werden zahlreiche Akteure mit unterschiedlichen Hintergr{\"u}nden und fachlichen Expertisen in Einzel- oder Verbundvorhaben vereint, die jedoch weitestgehend unabh{\"a}ngig voneinander durchgef{\"u}hrt werden. Vor dem Hintergrund, dass gesamtgesellschaftliche Herausforderungen wie die globale Erw{\"a}rmung zunehmend disziplin{\"u}bergreifende L{\"o}sungsans{\"a}tze erfordern, sollten Vernetzungs- und Transferprozesse in Forschungsprogrammen st{\"a}rker in den Fokus r{\"u}cken. Mit der Implementierung einer Begleitforschung kann dieser Forderung Rechnung getragen werden. Begleitforschung unterscheidet sich in ihrer Herangehensweise und ihrer Zielvorstellung von den „{\"u}blichen" Projekten und kann in unterschiedlichen theoretischen Reinformen auftreten. Verk{\"u}rzt dargestellt agiert sie entweder (1) inhaltlich komplement{\"a}r zu den jeweiligen Forschungsprojekten, (2) auf einer Metaebene mit Fokus auf die Prozesse im Forschungsprogramm oder (3) als integrierende, synthetisierende Instanz, f{\"u}r die die Vernetzung der Projekte im Forschungsprogramm sowie der Wissenstransfer von Bedeutung sind. Zwar sind diese Formen analytisch in theoretische Reinformen trennbar, in der Praxis ergibt sich in der Regel jedoch ein Mix aus allen dreien. In diesem Zusammenhang schließt die vorliegende Dissertation als erg{\"a}nzende Studie an bisherige Ans{\"a}tze zum methodischen Handwerkszeug der Begleitforschung an und fokussiert auf folgende Fragestellungen: Auf welcher Basis kann die Vernetzung der Akteure in einem Forschungsprogramm durchgef{\"u}hrt werden, um diese effektiv zusammenzubringen? Welche weiteren methodischen Elemente sollten daran ansetzen, um einen Mehrwert zu generieren, der die Summe der Einzelergebnisse des Forschungsprogrammes {\"u}bersteigt? Von welcher Art kann dann ein solcher Mehrwert sein und welche Rolle spielt dabei die Begleitforschung? Das erste methodische Element bildet die Erhebung und Aufbereitung einer Ausgangsdatenbasis. Durch eine auf semantischer Analyse basierenden Verschlagwortung projektbezogener Texte l{\"a}sst sich eine umfassende Datenbasis aus den Inhalten der Forschungsprojekte generieren. Die Schlagw{\"o}rter werden dabei anhand eines kontrollierten Vokabulars in einem Schlagwortkatalog strukturiert. Parallel dazu werden sie wiederum den jeweiligen Projekten zugeordnet, wodurch diese thematische Merkmale erhalten. Um thematische {\"U}berschneidungen zwischen Forschungsprojekten sichtbar und interpretierbar zu machen, beinhaltet das zweite Element Ans{\"a}tze zur Visualisierung. Dazu werden die Informationen in einen Netzwerkgraphen transferiert, der sowohl alle im Forschungsprogramm involvierten Projekte als auch die identifizierten Schlagw{\"o}rter in Relation zueinander abbilden kann. So kann zum Beispiel sichtbar gemacht werden, welche Forschungsprojekte sich auf Basis ihrer Inhalte „n{\"a}her" sind als andere. Genau diese Information wird im dritten methodischen Element als Planungsgrundlage f{\"u}r unterschiedliche Veranstaltungsformate wie Arbeitstagungen oder Transferwerkst{\"a}tten genutzt. Das vierte methodische Element umfasst die Synthesebildung. Diese gestaltet sich als Prozess {\"u}ber den gesamten Zeitraum der Zusammenarbeit zwischen Begleitforschung und den weiteren Forschungsprojekten hinweg, da in die Synthese unter anderem Zwischen-, Teil- und Endergebnisse der Projekte einfließen, genauso wie Inhalte aus den unterschiedlichen Veranstaltungen. Letztendlich ist dieses vierte Element auch das Mittel, um aus den integrierten und synthetisierten Informationen Handlungsempfehlungen f{\"u}r zuk{\"u}nftige Vorhaben abzuleiten. Die Erarbeitung der methodischen Elemente erfolgte im laufenden Prozess des Begleitforschungsprojektes KlimAgrar, welches der vorliegenden Dissertation als Fallbeispiel dient und dessen Hintergr{\"u}nde in der Thematik Klimaschutz und Klimaanpassung in der Landwirtschaft im Text ausf{\"u}hrlich erl{\"a}utert werden.},
  language  = {de}
}
@phdthesis{Codeco2019,
  author    = {Codeco, Marta Sofia Ferreira},
  title     = {Constraining the hydrology at Minas da Panasqueira W-Sn-Cu deposit, Portugal},
  doi       = {10.25932/publishup-42975},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429752},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxviii, 232},
  year      = {2019},
  abstract  = {This dissertation combines field and geochemical observations and analyses with numerical modeling to understand the formation of vein-hosted Sn-W ore in the Panasqueira deposit of Portugal, which is among the ten largest worldwide. The deposit is located above a granite body that is altered by magmatic-hydrothermal fluids in its upper part (greisen). These fluids are thought to be the source of metals, but that was still under debate. The goal of this study is to determine the composition and temperature of hydrothermal fluids at Panasqueira, and with that information to construct a numerical model of the hydrothermal system. The focus is on analysis of the minerals tourmaline and white mica, which formed during mineralization and are widespread throughout the deposit. Tourmaline occurs mainly in alteration zones around mineralized veins and is less abundant in the vein margins. White mica is more widespread. It is abundant in vein margins as well as alteration zones, and also occurs in the granite greisen. The laboratory work involved in-situ microanalysis of major- and trace elements in tourmaline and white mica, and boron-isotope analysis in both minerals by secondary ion mass spectrometry (SIMS). The boron-isotope composition of tourmaline and white mica suggests a magmatic source. Comparison of hydrothermally-altered and unaltered rocks from drill cores shows that the ore metals (W, Sn, Cu, and Zn) and As, F, Li, Rb, and Cs were introduced during the alteration. Most of these elements are also enriched in tourmaline and mica, which confirms their potential value as exploration guides to Sn-W ores elsewhere. The thermal evolution of the hydrothermal system was estimated by B-isotope exchange thermometry and the Ti-in-quartz method. Both methods yielded similar temperatures for the early hydrothermal phase: 430° to 460°C for B-isotopes and 503° ± 24°C for Ti-in-quartz. Mineral pairs from a late fault zone yield significantly lower median temperatures of 250°C. The combined results of thermometry with variations in chemical and B-isotope composition of tourmaline and mica suggest that a similar magmatic-hydrothermal fluid was active at all stages of mineralization. Mineralization in the late stage shows the same B-isotope composition as in the main stage despite a ca. 250°C cooling, which supports a multiple injection model of magmatic-hydrothermal fluids. Two-dimensional numerical simulations of convection in a multiphase NaCl hydrothermal system were conducted: (a) in order to test a new approach (lower dimensional elements) for flow through fractures and faults and (b) in order to identify conditions for horizontal fluid flow as observed in the flat-lying veins at Panasqueira. The results show that fluid flow over an intrusion (heat and fluid source) develops a horizontal component if there is sufficient fracture connectivity. Late, steep fault zones have been identified in the deposit area, which locally contain low-temperature Zn-Pb mineralization. The model results confirm that the presence of subvertical faults with enhanced permeability play a crucial role in the ascent of magmatic fluids to the surface and the recharge of meteoric waters. Finally, our model results suggest that recharge of meteoric fluids and mixing processes may be important at later stages, while flow of magmatic fluids dominate the early stages of the hydrothermal fluid circulation.},
  language  = {en}
}
@phdthesis{Schmidt2024,
  author    = {Schmidt, Lena Katharina},
  title     = {Altered hydrological and sediment dynamics in high-alpine areas - Exploring the potential of machine-learning for estimating past and future changes},
  doi       = {10.25932/publishup-62330},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-623302},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxi, 129},
  year      = {2024},
  abstract  = {Climate change fundamentally transforms glaciated high-alpine regions, with well-known cryospheric and hydrological implications, such as accelerating glacier retreat, transiently increased runoff, longer snow-free periods and more frequent and intense summer rainstorms. These changes affect the availability and transport of sediments in high alpine areas by altering the interaction and intensity of different erosion processes and catchment properties. Gaining insight into the future alterations in suspended sediment transport by high alpine streams is crucial, given its wide-ranging implications, e.g. for flood damage potential, flood hazard in downstream river reaches, hydropower production, riverine ecology and water quality. However, the current understanding of how climate change will impact suspended sediment dynamics in these high alpine regions is limited. For one, this is due to the scarcity of measurement time series that are long enough to e.g. infer trends. On the other hand, it is difficult - if not impossible - to develop process-based models, due to the complexity and multitude of processes involved in high alpine sediment dynamics. Therefore, knowledge has so far been confined to conceptual models (which do not facilitate deriving concrete timings or magnitudes for individual catchments) or qualitative estimates ('higher export in warmer years') that may not be able to capture decreases in sediment export. Recently, machine-learning approaches have gained in popularity for modeling sediment dynamics, since their black box nature tailors them to the problem at hand, i.e. relatively well-understood input and output data, linked by very complex processes. Therefore, the overarching aim of this thesis is to estimate sediment export from the high alpine {\"O}tztal valley in Tyrol, Austria, over decadal timescales in the past and future - i.e. timescales relevant to anthropogenic climate change. This is achieved by informing, extending, evaluating and applying a quantile regression forest (QRF) approach, i.e. a nonparametric, multivariate machine-learning technique based on random forest. The first study included in this thesis aimed to understand present sediment dynamics, i.e. in the period with available measurements (up to 15 years). To inform the modeling setup for the two subsequent studies, this study identified the most important predictors, areas within the catchments and time periods. To that end, water and sediment yields from three nested gauges in the upper {\"O}tztal, Vent, S{\"o}lden and Tumpen (98 to almost 800 km² catchment area, 930 to 3772 m a.s.l.) were analyzed for their distribution in space, their seasonality and spatial differences therein, and the relative importance of short-term events. The findings suggest that the areas situated above 2500 m a.s.l., containing glacier tongues and recently deglaciated areas, play a pivotal role in sediment generation across all sub-catchments. In contrast, precipitation events were relatively unimportant (on average, 21 \% of annual sediment yield was associated to precipitation events). Thus, the second and third study focused on the Vent catchment and its sub-catchment above gauge Vernagt (11.4 and 98 km², 1891 to 3772 m a.s.l.), due to their higher share of areas above 2500 m. Additionally, they included discharge, precipitation and air temperature (as well as their antecedent conditions) as predictors. The second study aimed to estimate sediment export since the 1960s/70s at gauges Vent and Vernagt. This was facilitated by the availability of long records of the predictors, discharge, precipitation and air temperature, and shorter records (four and 15 years) of turbidity-derived sediment concentrations at the two gauges. The third study aimed to estimate future sediment export until 2100, by applying the QRF models developed in the second study to pre-existing precipitation and temperature projections (EURO-CORDEX) and discharge projections (physically-based hydroclimatological and snow model AMUNDSEN) for the three representative concentration pathways RCP2.6, RCP4.5 and RCP8.5. The combined results of the second and third study show overall increasing sediment export in the past and decreasing export in the future. This suggests that peak sediment is underway or has already passed - unless precipitation changes unfold differently than represented in the projections or changes in the catchment erodibility prevail and override these trends. Despite the overall future decrease, very high sediment export is possible in response to precipitation events. This two-fold development has important implications for managing sediment, flood hazard and riverine ecology. This thesis shows that QRF can be a very useful tool to model sediment export in high-alpine areas. Several validations in the second study showed good performance of QRF and its superiority to traditional sediment rating curves - especially in periods that contained high sediment export events, which points to its ability to deal with threshold effects. A technical limitation of QRF is the inability to extrapolate beyond the range of values represented in the training data. We assessed the number and severity of such out-of-observation-range (OOOR) days in both studies, which showed that there were few OOOR days in the second study and that uncertainties associated with OOOR days were small before 2070 in the third study. As the pre-processed data and model code have been made publically available, future studies can easily test further approaches or apply QRF to further catchments.},
  language  = {en}
}
@phdthesis{Zali2023,
  author    = {Zali, Zahra},
  title     = {Volcanic tremor analysis based on advanced signal processing concepts including music information retrieval (MIR) strategies},
  doi       = {10.25932/publishup-61086},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-610866},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 95},
  year      = {2023},
  abstract  = {Volcanoes are one of the Earth's most dynamic zones and responsible for many changes in our planet. Volcano seismology aims to provide an understanding of the physical processes in volcanic systems and anticipate the style and timing of eruptions by analyzing the seismic records. Volcanic tremor signals are usually observed in the seismic records before or during volcanic eruptions. Their analysis contributes to evaluate the evolving volcanic activity and potentially predict eruptions. Years of continuous seismic monitoring now provide useful information for operational eruption forecasting. The continuously growing amount of seismic recordings, however, poses a challenge for analysis, information extraction, and interpretation, to support timely decision making during volcanic crises. Furthermore, the complexity of eruption processes and precursory activities makes the analysis challenging. A challenge in studying seismic signals of volcanic origin is the coexistence of transient signal swarms and long-lasting volcanic tremor signals. Separating transient events from volcanic tremors can, therefore, contribute to improving our understanding of the underlying physical processes. Some similar issues (data reduction, source separation, extraction, and classification) are addressed in the context of music information retrieval (MIR). The signal characteristics of acoustic and seismic recordings comprise a number of similarities. This thesis is going beyond classical signal analysis techniques usually employed in seismology by exploiting similarities of seismic and acoustic signals and building the information retrieval strategy on the expertise developed in the field of MIR. First, inspired by the idea of harmonic-percussive separation (HPS) in musical signal processing, I have developed a method to extract harmonic volcanic tremor signals and to detect transient events from seismic recordings. This provides a clean tremor signal suitable for tremor investigation along with a characteristic function suitable for earthquake detection. Second, using HPS algorithms, I have developed a noise reduction technique for seismic signals. This method is especially useful for denoising ocean bottom seismometers, which are highly contaminated by noise. The advantage of this method compared to other denoising techniques is that it doesn't introduce distortion to the broadband earthquake waveforms, which makes it reliable for different applications in passive seismological analysis. Third, to address the challenge of extracting information from high-dimensional data and investigating the complex eruptive phases, I have developed an advanced machine learning model that results in a comprehensive signal processing scheme for volcanic tremors. Using this method seismic signatures of major eruptive phases can be automatically detected. This helps to provide a chronology of the volcanic system. Also, this model is capable to detect weak precursory volcanic tremors prior to the eruption, which could be used as an indicator of imminent eruptive activity. The extracted patterns of seismicity and their temporal variations finally provide an explanation for the transition mechanism between eruptive phases.},
  language  = {en}
}
@phdthesis{Luft2015,
  author    = {Luft, Laura Charlotte},
  title     = {Bridging the gap between science and nature conservation practice},
  school      = {Universit{\"a}t Potsdam},
  pages     = {173},
  year      = {2015},
  language  = {en}
}
@phdthesis{Korges2019,
  author    = {Korges, Maximilian},
  title     = {Constraining the hydrology of intrusion-related ore deposits with fluid inclusions and numerical modeling},
  doi       = {10.25932/publishup-43484},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434843},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VIII, 99},
  year      = {2019},
  abstract  = {Magmatic-hydrothermal fluids are responsible for numerous mineralization types, including porphyry copper and granite related tin-tungsten (Sn-W) deposits. Ore formation is dependent on various factors, including, the pressure and temperature regime of the intrusions, the chemical composition of the magma and hydrothermal fluids, and fluid rock interaction during the ascent. Fluid inclusions have potential to provide direct information on the temperature, salinity, pressure and chemical composition of fluids responsible for ore formation. Numerical modeling allows the parametrization of pluton features that cannot be analyzed directly via geological observations. Microthermometry of fluid inclusions from the Zinnwald Sn-W deposit, Erzgebirge, Germany / Czech Republic, provide evidence that the greisen mineralization is associated with a low salinity (2-10 wt.\% NaCl eq.) fluid with homogenization temperatures between 350°C and 400°C. Quartzes from numerous veins are host to inclusions with the same temperatures and salinities, whereas cassiterite- and wolframite-hosted assemblages with slightly lower temperatures (around 350°C) and higher salinities (ca. 15 wt. NaCl eq.). Further, rare quartz samples contained boiling assemblages consisting of coexisting brine and vapor phases. The formation of ore minerals within the greisen is driven by invasive fluid-rock interaction, resulting in the loss of complexing agents (Cl-) leading to precipitation of cassiterite. The fluid inclusion record in the veins suggests boiling as the main reason for cassiterite and wolframite mineralization. Ore and coexisting gangue minerals hosted different types of fluid inclusions where the beginning boiling processes are solely preserved by the ore minerals emphasizing the importance of microthermometry in ore minerals. Further, the study indicates that boiling as a precipitation mechanism can only occur in mineralization related to shallow intrusions whereas deeper plutons prevent the fluid from boiling and can therefore form tungsten mineralization in the distal regions. The tin mineralization in the H{\"a}mmerlein deposit, Erzgebirge, Germany, occurs within a skarn horizon and the underlying schist. Cassiterite within the skarn contains highly saline (30-50 wt\% NaCl eq.) fluid inclusions, with homogenization temperatures up to 500°C, whereas cassiterites from the schist and additional greisen samples contain inclusions of lower salinity (~5 wt\% NaCl eq.) and temperature (between 350 and 400°C). Inclusions in the gangue minerals (quartz, fluorite) preserve homogenization temperatures below 350°C and sphalerite showed the lowest homogenization temperatures (ca. 200°C) whereby all minerals (cassiterite from schist and greisen, gangue minerals and sphalerite) show similar salinity ranges (2-5 wt\% NaCl eq.). Similar trace element contents and linear trends in the chemistry of the inclusions suggest a common source fluid. The inclusion record in the H{\"a}mmerlein deposit documents an early exsolution of hot brines from the underlying granite which is responsible for the mineralization hosted by the skarn. Cassiterites in schist and greisen are mainly forming due to fluid-rock interaction at lower temperatures. The low temperature inclusions documented in the sphalerite mineralization as well as their generally low trace element composition in comparison to the other minerals suggests that their formation was induced by mixing with meteoric fluids. Numerical simulations of magma chambers and overlying copper distribution document the importance of incremental growth by sills. We analyzed the cooling behavior at variable injection intervals as well as sill thicknesses. The models suggest that magma accumulation requires volumetric injection rates of at least 4 x 10-4 km³/y. These injection rates are further needed to form a stable magmatic-hydrothermal fluid plume above the magma chamber to ensure a constant copper precipitation and enrichment within a confined location in order to form high-grade ore shells within a narrow geological timeframe between 50 and 100 kyrs as suggested for porphyry copper deposits. The highest copper enrichment can be found in regions with steep temperature gradients, typical of regions where the magmatic-hydrothermal fluid meets the cooler ambient fluids.},
  language  = {en}
}
@phdthesis{Tian2014,
  author    = {Tian, Fang},
  title     = {Vegetation and environmental changes on millennial, centennial and decadal time-scales in central Mongolia and their driving forces},
  school      = {Universit{\"a}t Potsdam},
  pages     = {139},
  year      = {2014},
  language  = {en}
}
@phdthesis{RodriguezZuluaga2020,
  author    = {Rodriguez Zuluaga, Juan},
  title     = {Electric and magnetic characteristics of equatorial plasma depletions},
  doi       = {10.25932/publishup-44587},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445873},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvi, 87},
  year      = {2020},
  abstract  = {Near-Earth space represents a significant scientific and technological challenge. Particularly at magnetic low-latitudes, the horizontal magnetic field geometry at the dip equator and its closed field-lines support the existence of a distinct electric current system, abrupt electric field variations and the development of plasma irregularities. Of particular interest are small-scale irregularities associated with equatorial plasma depletions (EPDs). They are responsible for the disruption of trans-ionospheric radio waves used for navigation, communication, and Earth observation. The fast increase of satellite missions makes it imperative to study the near-Earth space, especially the phenomena known to harm space technology or disrupt their signals. EPDs correspond to the large-scale structure (i.e., tens to hundreds of kilometers) of topside F region irregularities commonly known as Spread F. They are observed as depleted-plasma density channels aligned with the ambient magnetic field in the post-sunset low-latitude ionosphere. Although the climatological variability of their occurrence in terms of season, longitude, local time and solar flux is well-known, their day to day variability is not. The sparse observations from ground-based instruments like radars and the few simultaneous measurements of ionospheric parameters by space-based instruments have left gaps in the knowledge of EPDs essential to comprehend their variability. In this dissertation, I profited from the unique observations of the ESA's Swarm constellation mission launched in November 2013 to tackle three issues that revealed novel and significant results on the current knowledge of EPDs. I used Swarm's measurements of the electron density, magnetic, and electric fields to answer, (1.) what is the direction of propagation of the electromagnetic energy associated with EPDs?, (2.) what are the spatial and temporal characteristics of the electric currents (field-aligned and diamagnetic currents) related to EPDs, i.e., seasonal/geographical, and local time dependencies?, and (3.) under what conditions does the balance between magnetic and plasma pressure across EPDs occur? The results indicate that: (1.) The electromagnetic energy associated with EPDs presents a preference for interhemispheric flows; that is, the related Poynting flux directs from one magnetic hemisphere to the other and varies with longitude and season. (2.) The field-aligned currents at the edges of EPDs are interhemispheric. They generally close in the hemisphere with the highest Pedersen conductance. Such hemispherical preference presents a seasonal/longitudinal dependence. The diamagnetic currents increase or decrease the magnetic pressure inside EPDs. These two effects rely on variations of the plasma temperature inside the EPDs that depend on longitude and local time. (3.) EPDs present lower or higher plasma pressure than the ambient. For low-pressure EPDs the plasma pressure gradients are mostly dominated by variations of the plasma density so that variations of the temperature are negligible. High-pressure EPDs suggest significant temperature variations with magnitudes of approximately twice the ambient. Since their occurrence is more frequent in the vicinity of the South Atlantic magnetic anomaly, such high temperatures are suggested to be due to particle precipitation. In a broader context, this dissertation shows how dedicated satellite missions with high-resolution capabilities improve the specification of the low-latitude ionospheric electrodynamics and expand knowledge on EPDs which is valuable for current and future communication, navigation, and Earth-observing missions. The contributions of this investigation represent several 'firsts' in the study of EPDs: (1.) The first observational evidence of interhemispheric electromagnetic energy flux and field-aligned currents. (2.) The first spatial and temporal characterization of EPDs based on their associated field-aligned and diamagnetic currents. (3.) The first evidence of high plasma pressure in regions of depleted plasma density in the ionosphere. These findings provide new insights that promise to advance our current knowledge of not only EPDs but the low-latitude post-sunset ionosphere environment.},
  language  = {en}
}
@phdthesis{Liebs2014,
  author    = {Liebs, G{\"o}ran},
  title     = {Ground penetration radar wave velocities and their uncertainties},
  doi       = {10.25932/publishup-43680},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436807},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ii, 106},
  year      = {2014},
  abstract  = {We develop three new approaches for ground penetration wave velocity calcultaions. The first is based on linear moveout spectra to find the optimum ground wave velocity including uncertainties from multi-offset data gathers. We used synthetic data to illustrate the principles of the method and to investigate uncertainties in ground wave velocity estimates. To demonstrate the applicability of the approach to real data, we analyzed GPR data sets recorded at field sites in Canada over an annual cycle from Steelman \& Endres [2010]. The results obtained by this efficient and largely automated procedure agree well with the manual achieved results of Steelman \& Endres [2010], derived by a more laborious largely manual analysis strategy. Then we develop a second methodology to global invert reflection traveltimes with a particle swarm optimization approach more precise then conventional spectral NMO-based velocity analysis (e.g., Greaves et al. [1996]). For global optimization, we use particle swarm optimization (PSO; Kennedy \& Eberhart [1995]) in the combination with a fast eikonal solver as forward solver (Sethian [1996]; Fomel [1997a]; Sethian \& Popovici [1999]). This methodology allows us to generate reliability CMP derived models of subsurface velocities and water content including uncertainties. We test this method with synthetic data to study the behavior of the PSO algorithm. Afterward, We use this method to analyze our field data from a well constrained test site in Horstwalde, Germany. The achieved velocity models from field data showed good agreement to borehole logging and direct-push data (Schmelzbach et al. [2011]) at the same site position. For the third method we implement a global optimization approach also based on PSO to invert direct-arrival traveltimes of VRP data to obtain high resolution 1D velocity models including quantitative estimates of uncertainty. Our intensive tests with several traveltime data sets helped to understand the behavior of PSO algorithm for inversion. Integration of the velocity model to VRP reflection imaging and attenuation model improved the potential of VRP surveying. Using field data, we examine this novel analysis strategy for the development of petrophysical models and the linking between GPR borehole and other logging data to surface GPR reflection data.},
  language  = {de}
}
@phdthesis{Allroggen2015,
  author    = {Allroggen, Niklas},
  title     = {Observation of subsurface flow from the surface : applications of ground-penetrating radar},
  school      = {Universit{\"a}t Potsdam},
  pages     = {67},
  year      = {2015},
  language  = {en}
}
@phdthesis{Marquart2019,
  author    = {Marquart, Arnim},
  title     = {Feedbacks between macropores and soil water infiltration in semi-arid savanna systems},
  pages     = {146},
  year      = {2019},
  language  = {en}
}
@phdthesis{Zeitz2022,
  author    = {Zeitz, Maria},
  title     = {Modeling the future resilience of the Greenland Ice Sheet},
  doi       = {10.25932/publishup-56883},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-568839},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 189},
  year      = {2022},
  abstract  = {The Greenland Ice Sheet is the second-largest mass of ice on Earth. Being almost 2000 km long, more than 700 km wide, and more than 3 km thick at the summit, it holds enough ice to raise global sea levels by 7m if melted completely. Despite its massive size, it is particularly vulnerable to anthropogenic climate change: temperatures over the Greenland Ice Sheet have increased by more than 2.7◦C in the past 30 years, twice as much as the global mean temperature. Consequently, the ice sheet has been significantly losing mass since the 1980s and the rate of loss has increased sixfold since then. Moreover, it is one of the potential tipping elements of the Earth System, which might undergo irreversible change once a warming threshold is exceeded. This thesis aims at extending the understanding of the resilience of the Greenland Ice Sheet against global warming by analyzing processes and feedbacks relevant to its centennial to multi-millennial stability using ice sheet modeling. One of these feedbacks, the melt-elevation-feedback is driven by the temperature rise with decreasing altitudes: As the ice sheet melts, its thickness and surface elevation decrease, exposing the ice surface to warmer air and thus increasing the melt rates even further. The glacial isostatic adjustment (GIA) can partly mitigate this melt-elevation feedback as the bedrock lifts in response to an ice load decrease, forming the negative GIA feedback. In my thesis, I show that the interaction between these two competing feedbacks can lead to qualitatively different dynamical responses of the Greenland Ice Sheet to warming - from permanent loss to incomplete recovery, depending on the feedback parameters. My research shows that the interaction of those feedbacks can initiate self-sustained oscillations of the ice volume while the climate forcing remains constant. Furthermore, the increased surface melt changes the optical properties of the snow or ice surface, e.g. by lowering their albedo, which in turn enhances melt rates - a process known as the melt-albedo feedback. Process-based ice sheet models often neglect this melt-albedo feedback. To close this gap, I implemented a simplified version of the diurnal Energy Balance Model, a computationally efficient approach that can capture the first-order effects of the melt-albedo feedback, into the Parallel Ice Sheet Model (PISM). Using the coupled model, I show in warming experiments that the melt-albedo feedback almost doubles the ice loss until the year 2300 under the low greenhouse gas emission scenario RCP2.6, compared to simulations where the melt-albedo feedback is neglected, and adds up to 58\% additional ice loss under the high emission scenario RCP8.5. Moreover, I find that the melt-albedo feedback dominates the ice loss until 2300, compared to the melt-elevation feedback. Another process that could influence the resilience of the Greenland Ice Sheet is the warming induced softening of the ice and the resulting increase in flow. In my thesis, I show with PISM how the uncertainty in Glen's flow law impacts the simulated response to warming. In a flow line setup at fixed climatic mass balance, the uncertainty in flow parameters leads to a range of ice loss comparable to the range caused by different warming levels. While I focus on fundamental processes, feedbacks, and their interactions in the first three projects of my thesis, I also explore the impact of specific climate scenarios on the sea level rise contribution of the Greenland Ice Sheet. To increase the carbon budget flexibility, some warming scenarios - while still staying within the limits of the Paris Agreement - include a temporal overshoot of global warming. I show that an overshoot by 0.4◦C increases the short-term and long-term ice loss from Greenland by several centimeters. The long-term increase is driven by the warming at high latitudes, which persists even when global warming is reversed. This leads to a substantial long-term commitment of the sea level rise contribution from the Greenland Ice Sheet. Overall, in my thesis I show that the melt-albedo feedback is most relevant for the ice loss of the Greenland Ice Sheet on centennial timescales. In contrast, the melt-elevation feedback and its interplay with the GIA feedback become increasingly relevant on millennial timescales. All of these influence the resilience of the Greenland Ice Sheet against global warming, in the near future and on the long term.},
  language  = {en}
}
@phdthesis{Koyan2024,
  author    = {Koyan, Philipp},
  title     = {3D attribute analysis and classification to interpret ground-penetrating radar (GPR) data collected across sedimentary environments: Synthetic studies and field examples},
  doi       = {10.25932/publishup-63948},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-639488},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 115, A51},
  year      = {2024},
  abstract  = {Die Untersuchung des oberfl{\"a}chennahen Untergrundes erfolgt heutzutage bei Frage- stellungen aus den Bereichen des Bauwesens, der Arch{\"a}ologie oder der Geologie und Hydrologie oft mittels zerst{\"o}rungsfreier beziehungsweise zerst{\"o}rungsarmer Methoden der angewandten Geophysik. Ein Bereich, der eine immer zentralere Rolle in Forschung und Ingenieurwesen einnimmt, ist die Untersuchung von sediment{\"a}ren Umgebungen, zum Beispiel zur Charakterisierung oberfl{\"a}chennaher Grundwassersysteme. Ein in diesem Kontext h{\"a}ufig eingesetztes Verfahren ist das des Georadars (oftmals GPR - aus dem Englischen ground-penetrating radar). Dabei werden kurze elektromagnetische Impulse von einer Antenne in den Untergrund ausgesendet, welche dort wiederum an Kontrasten der elektromagnetischen Eigenschaften (wie zum Beispiel an der Grundwasseroberfl{\"a}che) reflektiert, gebrochen oder gestreut werden. Eine Empfangsantenne zeichnet diese Signale in Form derer Amplituden und Laufzeiten auf. Eine Analyse dieser aufgezeichneten Signale erm{\"o}glicht Aussagen {\"u}ber den Untergrund, beispielsweise {\"u}ber die Tiefenlage der Grundwasseroberfl{\"a}che oder die Lagerung und Charakteristika oberfl{\"a}chennaher Sedimentschichten. Dank des hohen Aufl{\"o}sungsverm{\"o}gens der GPR-Methode sowie stetiger technologischer Entwicklungen erfolgt heutzutage die Aufzeichnung von GPR- Daten immer h{\"a}ufiger in 3D. Trotz des hohen zeitlichen und technischen Aufwandes f{\"u}r die Datenakquisition und -bearbeitung werden die resultierenden 3D-Datens{\"a}tze, welche den Untergrund hochaufl{\"o}send abbilden, typischerweise von Hand interpretiert. Dies ist in der Regel ein {\"a}ußerst zeitaufwendiger Analyseschritt. Daher werden oft repr{\"a}sentative 2D-Schnitte aus dem 3D-Datensatz gew{\"a}hlt, in denen markante Reflektionsstrukuren markiert werden. Aus diesen Strukturen werden dann sich {\"a}hnelnde Bereiche im Untergrund als so genannte Radar-Fazies zusammengefasst. Die anhand von 2D-Schnitten erlangten Resultate werden dann als repr{\"a}sentativ f{\"u}r die gesamte untersuchte Fl{\"a}che angesehen. In dieser Form durchgef{\"u}hrte Interpretationen sind folglich oft unvollst{\"a}ndig sowie zudem in hohem Maße von der Expertise der Interpretierenden abh{\"a}ngig und daher in der Regel nicht reproduzierbar. Eine vielversprechende Alternative beziehungsweise Erg{\"a}nzung zur manuellen In- terpretation ist die Verwendung von so genannten GPR-Attributen. Dabei werden nicht die aufgezeichneten Daten selbst, sondern daraus abgeleitete Gr{\"o}ßen, welche die markanten Reflexionsstrukturen in 3D charakterisieren, zur Interpretation herangezogen. In dieser Arbeit wird anhand verschiedener Feld- und Modelldatens{\"a}tze untersucht, welche Attribute sich daf{\"u}r insbesondere eignen. Zudem zeigt diese Arbeit, wie ausgew{\"a}hlte Attribute mittels spezieller Bearbeitungs- und Klassifizierungsmethoden zur Erstellung von 3D-Faziesmodellen genutzt werden k{\"o}nnen. Dank der M{\"o}glichkeit der Erstellung so genannter attributbasierter 3D-GPR-Faziesmodelle k{\"o}nnen zuk{\"u}nftige Interpretationen zu gewissen Teilen automatisiert und somit effizienter durchgef{\"u}hrt werden. Weiterhin beschreiben die so erhaltenen Resultate den untersuchten Untergrund in reproduzierbarer Art und Weise sowie umf{\"a}nglicher als es bisher mittels manueller Interpretationsmethoden typischerweise m{\"o}glich war.},
  language  = {en}
}
@phdthesis{Ghani2019,
  author    = {Ghani, Humaad},
  title     = {Structural evolution of the Kohat and Potwar fold and thrust belts of Pakistan},
  doi       = {10.25932/publishup-44077},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440775},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 121},
  year      = {2019},
  abstract  = {Fold and thrust belts are characteristic features of collisional orogen that grow laterally through time by deforming the upper crust in response to stresses caused by convergence. The deformation propagation in the upper crust is accommodated by shortening along major folds and thrusts. The formation of these structures is influenced by the mechanical strength of d{\´e}collements, basement architecture, presence of preexisting structures and taper of the wedge. These factors control not only the sequence of deformation but also cause differences in the structural style. The Himalayan fold and thrust belt exhibits significant differences in the structural style from east to west. The external zone of the Himalayan fold and thrust belt, also called the Subhimalaya, has been extensively studied to understand the temporal development and differences in the structural style in Bhutan, Nepal and India; however, the Subhimalaya in Pakistan remains poorly studied. The Kohat and Potwar fold and thrust belts (herein called Kohat and Potwar) represent the Subhimalaya in Pakistan. The Main Boundary Thrust (MBT) marks the northern boundary of both Kohat and Potwar, showing that these belts are genetically linked to foreland-vergent deformation within the Himalayan orogen, despite the pronounced contrast in structural style. This contrast becomes more pronounced toward south, where the active strike-slip Kalabagh Fault Zone links with the Kohat and Potwar range fronts, known as the Surghar Range and the Salt Range, respectively. The Surghar and Salt Ranges developed above the Surghar Thrust (SGT) and Main Frontal Thrust (MFT). In order to understand the structural style and spatiotemporal development of the major structures in Kohat and Potwar, I have used structural modeling and low temperature thermochronolgy methods in this study. The structural modeling is based on construction of balanced cross-sections by integrating surface geology, seismic reflection profiles and well data. In order to constrain the timing and magnitude of exhumation, I used apatite (U-Th-Sm)/He (AHe) and apatite fission track (AFT) dating. The results obtained from both methods are combined to document the Paleozoic to Recent history of Kohat and Potwar. The results of this research suggest two major events in the deformation history. The first major deformation event is related to Late Paleozoic rifting associated with the development of the Neo-Tethys Ocean. The second major deformation event is related to the Late Miocene to Pliocene development of the Himalayan fold and thrust belt in the Kohat and Potwar. The Late Paleozoic rifting is deciphered by inverse thermal modelling of detrital AFT and AHe ages from the Salt Range. The process of rifting in this area created normal faulting that resulted in the exhumation/erosion of Early to Middle Paleozoic strata, forming a major unconformity between Cambrian and Permian strata that is exposed today in the Salt Range. The normal faults formed in Late Paleozoic time played an important role in localizing the Miocene-Pliocene deformation in this area. The combination of structural reconstructions and thermochronologic data suggest that deformation initiated at 15±2 Ma on the SGT ramp in the southern part of Kohat. The early movement on the SGT accreted the foreland into the Kohat deforming wedge, forming the range front. The development of the MBT at 12±2 Ma formed the northern boundary of Kohat and Potwar. Deformation propagated south of the MBT in the Kohat on double d{\´e}collements and in the Potwar on a single basal d{\´e}collement. The double d{\´e}collement in the Kohat adopted an active roof-thrust deformation style that resulted in the disharmonic structural style in the upper and lower parts of the stratigraphic section. Incremental shortening resulted in the development of duplexes in the subsurface between two d{\´e}collements and imbrication above the roof thrust. Tectonic thickening caused by duplexes resulted in cooling and exhumation above the roof thrust by removal of a thick sequence of molasse strata. The structural modelling shows that the ramps on which duplexes formed in Kohat continue as tip lines of fault propagation folds in the Potwar. The absence of a double d{\´e}collement in the Potwar resulted in the preservation of a thick sequence of molasse strata there. The temporal data suggest that deformation propagated in-sequence from ~ 8 to 3 Ma in the northern part of Kohat and Potwar; however, internal deformation in the Kohat was more intense, probably required for maintaining a critical taper after a significant load was removed above the upper d{\´e}collement. In the southern part of Potwar, a steeper basement slope (β≥3°) and the presence of salt at the base of the stratigraphic section allowed for the complete preservation of the stratigraphic wedge, showcased by very little internal deformation. Activation of the MFT at ~4 Ma allowed the Salt Range to become the range front of the Potwar. The removal of a large amount of molasse strata above the MFT ramp enhanced the role of salt in shaping the structural style of the Salt Range and Kalabagh Fault Zone. Salt accumulation and migration resulted in the formation of normal faults in both areas. Salt migration in the Kalabagh fault zone has triggered out-of-sequence movement on ramps in the Kohat. The amount of shortening calculated between the MBT and the SGT in Kohat is 75±5 km and between the MBT and the MFT in Potwar is 65±5 km. A comparable amount of shortening is accommodated in the Kohat and Potwar despite their different widths: 70 km Kohat and 150 km Potwar. In summary, this research suggests that deformation switched between different structures during the last ~15 Ma through different modes of fault propagation, resulting in different structural styles and the out-of-sequence development of Kohat and Potwar.},
  language  = {en}
}
@phdthesis{Niederleithinger2010,
  author    = {Niederleithinger, Ernst},
  title     = {Optimierung und Erweiterung der Parallel-Seismik-Methode zur Bestimmung der L{\"a}nge von Fundamentpf{\"a}hlen},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-49191},
  school      = {Universit{\"a}t Potsdam},
  year      = {2010},
  abstract  = {Das Parallel-Seismik-Verfahren dient vor allem der nachtr{\"a}glichen L{\"a}ngenmessung von Fundamentpf{\"a}hlen oder {\"a}hnlichen Elementen zur Gr{\"u}ndung von Bauwerken. Eine solche Messung wird beispielsweise notwendig, wenn ein Geb{\"a}ude verst{\"a}rkt, erh{\"o}ht oder anders als bisher genutzt werden soll, aber keine Unterlagen mehr {\"u}ber die Fundamente vorhanden sind. Das Messprinzip des schon seit einigen Jahrzehnten bekannten Verfahrens ist relativ einfach: Auf dem Pfahlkopf wird meist durch Hammerschlag eine Stoßwelle erzeugt, die durch den Pfahl nach unten l{\"a}uft. Dabei wird Energie in den Boden abgegeben. Die abgestrahlten Wellen werden von Sensoren in einem parallel zum Pfahl hergestellten Bohrloch registriert. Aus den Laufzeiten lassen sich die materialspezifischen Wellengeschwindigkeiten im Pfahl und im Boden sowie die Pfahll{\"a}nge ermitteln. Bisher wurde meist ein sehr einfaches Verfahren zur Datenauswertung verwendet, das die L{\"a}nge der Pf{\"a}hle systematisch {\"u}bersch{\"a}tzt. In der vorliegenden Dissertation wurden die mathematisch-physikalischen Grundlagen beleuchtet und durch Computersimulation die Wellenausbreitung in Pfahl und Boden genau untersucht. Weitere Simulationen kl{\"a}rten den Einfluss verschiedener Mess- und Strukturparameter, beispielsweise den Einfluss von Bodenschichtung oder Fehlstellen im Pfahl. So konnte gekl{\"a}rt werden, in welchen F{\"a}llen mit dem Parallel-Seismik-Verfahren gute Ergebnisse erzielt werden k{\"o}nnen (z. B. bei Fundamenten in Sand oder Ton) und wo es an seine Grenzen st{\"o}ßt (z. B. bei Gr{\"u}ndung im Fels). Auf Basis dieser Ergebnisse entstand ein neuer mathematischer Formalismus zur Auswertung der Laufzeiten. In Verbindung mit einem Verfahren zur Dateninversion, d. h. der automatischen Anpassung der Unbekannten in den Gleichungen an die Messergebnisse, lassen sich sehr viel genauere Werte f{\"u}r die Pfahll{\"a}nge ermitteln als mit allen bisher publizierten Verfahren. Zudem kann man nun auch mit relativ großen Abst{\"a}nden zwischen Bohrloch und Pfahl (2 - 3 m) arbeiten. Die Methode wurde an simulierten Daten ausf{\"u}hrlich getestet. Die Messmethode und das neue Auswerteverfahren wurden in einer Reihe praktischer Anwendungen getestet - und dies fast immer erfolgreich. Nur in einem Fall komplizierter Fundamentgeometrie bei gleichzeitig sehr hoher Anforderung an die Genauigkeit war schon nach Simulationen klar, dass hier ein Einsatz nicht sinnvoll ist. Daf{\"u}r zeigte es sich, dass auch die L{\"a}nge von Pfahlw{\"a}nden und Spundw{\"a}nden ermittelt werden kann. Die Parallel-Seismik-Methode funktioniert als einziges verf{\"u}gbares Verfahren zur Fundamentl{\"a}ngenermittlung zugleich in den meisten Bodenarten sowie an metallischen und nichtmetallischen Fundamenten und kommt ohne Kalibrierung aus. Sie ist nun sehr viel breiter einsetzbar und liefert sehr viel genauere Ergebnisse. Die Simulationen zeigten noch Potential f{\"u}r Erweiterungen, zum Beispiel durch den Einsatz spezieller Sensoren, die zus{\"a}tzliche Wellentypen empfangen und unterscheiden k{\"o}nnen.},
  language  = {de}
}