@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} } @article{AichnerMakhmudovRajabovetal.2019, author = {Aichner, Bernhard and Makhmudov, Zafar and Rajabov, Iljomjon and Zhang, Qiong and Pausata, Francesco Salvatore R. and Werner, Martin and Heinecke, Liv and Kuessner, Marie L. and Feakins, Sarah J. and Sachse, Dirk and Mischke, Steffen}, title = {Hydroclimate in the Pamirs Was Driven by Changes in Precipitation-Evaporation Seasonality Since theLast Glacial Period}, series = {Geophysical research letters}, volume = {46}, journal = {Geophysical research letters}, number = {23}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1029/2019GL085202}, pages = {13972 -- 13983}, year = {2019}, abstract = {The Central Asian Pamir Mountains (Pamirs) are a high-altitude region sensitive to climatic change, with only few paleoclimatic records available. To examine the glacial-interglacial hydrological changes in the region, we analyzed the geochemical parameters of a 31-kyr record from Lake Karakul and performed a set of experiments with climate models to interpret the results. delta D values of terrestrial biomarkers showed insolation-driven trends reflecting major shifts of water vapor sources. For aquatic biomarkers, positive delta D shifts driven by changes in precipitation seasonality were observed at ca. 31-30, 28-26, and 17-14 kyr BP. Multiproxy paleoecological data and modelling results suggest that increased water availability, induced by decreased summer evaporation, triggered higher lake levels during those episodes, possibly synchronous to northern hemispheric rapid climate events. We conclude that seasonal changes in precipitation-evaporation balance significantly influenced the hydrological state of a large waterbody such as Lake Karakul, while annual precipitation amount and inflows remained fairly constant.}, language = {en} } @phdthesis{Barsch2003, author = {Barsch, Andreas}, title = {Zum Einfluss von Witterung und Klima auf den Landschaftszustand und die Landschaftsentwicklung im Uvs-Nuur-Becken (NW-Mongolei)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001184}, school = {Universit{\"a}t Potsdam}, year = {2003}, abstract = {Im Landschaftszustand und in der Landschaftsentwicklung kommen funktionale Beziehungen zwischen dem naturbedingten Energie-, Wasser- und Stoffhaushalt einerseits und den Auswirkungen der Landnutzung andererseits zum Ausdruck. Gegenw{\"a}rtig ver{\"a}ndert der globale Anstieg der bodennahen Temperaturen vielerorts den landschaftlichen Energie-, Wasser- und Stoffhaushalt, wobei besonders in Trockengebieten zu erwarten ist, dass dieser Trend in Verbindung mit einer unangepassten Landnutzung das Regenerationsverm{\"o}gen der Vegetation einschr{\"a}nkt und zur Zerst{\"o}rung der Bodendecke f{\"u}hrt. F{\"u}r die Mongolei und f{\"u}r benachbarte Gebiete Asiens sind in Szenarien zur globalen Erw{\"a}rmung hohe Werte des Temperaturanstiegs prognostiziert worden. Eine globale Einsch{\"a}tzung der anthropogen induzierten Bodendegradation hat diese Region als stark oder extrem stark betroffen eingestuft. Vor diesem Hintergrund wurde im Uvs-Nuur-Becken, das im Nordwesten der Mongolei und damit in einer der trockensten Regionen des Landes gelegen ist, untersucht, wie sich der globale Temperaturanstieg auf der lokalen und regionalen Ebene widerspiegelt und wie der Landschaftshaushalt dabei ver{\"a}ndert wird. Die Auswirkungen des sommerlichen Witterungsverlaufes auf den Landschaftszustand sind 1997 bis 1999 an einem Transsekt erfasst worden, das sich zwischen dem Kharkhiraa-Gebirge am Westrand des Beckens und dem See Uvs Nuur im Beckeninneren von den Polsterfluren und Matten der alpinen Stufe {\"u}ber die Gebirgswaldsteppe, die Trockensteppe bis zur Halbw{\"u}ste erstreckt. An neun Messpunkten wurden witterungsklimatische Daten in Verbindung mit Merkmalen der Vegetation, des Bodens und der Bodenfeuchte aufgenommen. Die im Sommer 1998 gewonnenen Messwerte wurden mit Hilfe einer Clusteranalyse geb{\"u}ndelt und verdichtet. Auf dieser Grundlage konnten landschaftliche Zustandsformen inhaltlich gekennzeichnet, zeitlich eingeordnet und durch Zeit-Verhaltens-Modelle (Stacks) abgebildet werden. Aus den Zeit-Verhaltens-Modellen wird ersichtlich, dass man Zustandsformen, in denen die Hitze und die Trockenheit des Sommers 1998 besonders stark zum Ausdruck kommen, an allen Messpunkten beobachten kann, nimmt man die Station auf dem fast 3.000 m hohen Gipfel des Khukh Uul sowie die grundwasserbeeinflusste Station in unmittelbarer Seen{\"a}he aus. In ihrer extremen Form sind Trockenperioden jedoch nur im Beckeninneren und am Fuß der Randgebirge, also in der Halbw{\"u}ste, in der Trockensteppe und in der Wiesensteppe aufgetreten. Im Bergwald sowie im Bereich der alpinen Matten und Polsterfluren fehlen sie. Am st{\"a}rksten sind die grundwasserfreien Bereiche der Halbw{\"u}ste von der Hitze und Niederschlagsarmut des Sommers 1998 betroffen. An vier F{\"u}nfteln der Tage des Beobachtungszeitraumes herrscht an diesem Messpunkt extreme Trockenheit. Es f{\"a}llt entweder gar kein Niederschlag oder nur so wenig, dass der seit dem Fr{\"u}hjahr ersch{\"o}pfte Bodenwasservorrat nicht aufgef{\"u}llt wird. Das Verh{\"a}ltnis zwischen Niederschlag und potenzieller Verdunstung liegt hier bei 1:12. In der Halbw{\"u}ste zeichnet sich eine fortschreitende Desertifikation ab, zumal hier eine nichtangepasste Weidenutzung dominiert, in der Ziegen eine immer gr{\"o}ßere Rolle spielen. Dies gilt insbesondere f{\"u}r Bereiche in Siedlungsn{\"a}he. {\"O}rtlich ist auch der Bestand der Trockensteppe gef{\"a}hrdet, die sich an die Halbw{\"u}ste zum Beckenrand hin anschließt. Hier ist nicht nur die Viehdichte am h{\"o}chsten, sondern hier werden auch die meisten unbefestigten Fahrwege wild angelegt und die Bodendecke damit zerst{\"o}rt. Dies kann im Endeffekt zu einem {\"U}bergreifen von Prozessen der Desertifikation f{\"u}hren. Aus methodischer Sicht zeigt sich, dass die Kennzeichnung landschaftlicher Zustandsformen durch Zeit-Verhaltens-Modelle die Ermittlung der Auswirkungen von Witterung und Klima auf den Landschaftszustand erleichtert, da sie deren Aussage konzentriert. Zur Interpretation der Ergebnisse ist jedoch ein R{\"u}ckgriff auf die beschreibende Darstellung der Messwerte notwendig. Die im westlichen Uvs-Nuur-Becken und seinen Randgebirgen angewandte Verfahrensweise erm{\"o}glicht es, globale Aussagen zur globalen Erw{\"a}rmung der Kontinente regional oder lokal zu {\"u}berpr{\"u}fen und zu untersetzen."}, language = {de} } @misc{BoersGoswamiGhil2017, author = {Boers, Niklas and Goswami, Bedartha and Ghil, Michael}, title = {A complete representation of uncertainties in layer-counted paleoclimatic archives}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {641}, issn = {1866-8372}, doi = {10.25932/publishup-41803}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418030}, pages = {12}, year = {2017}, abstract = {Accurate time series representation of paleoclimatic proxy records is challenging because such records involve dating errors in addition to proxy measurement errors. Rigorous attention is rarely given to age uncertainties in paleoclimatic research, although the latter can severely bias the results of proxy record analysis. Here, we introduce a Bayesian approach to represent layer-counted proxy records - such as ice cores, sediments, corals, or tree rings - as sequences of probability distributions on absolute, error-free time axes. The method accounts for both proxy measurement errors and uncertainties arising from layer-counting-based dating of the records. An application to oxygen isotope ratios from the North Greenland Ice Core Project (NGRIP) record reveals that the counting errors, although seemingly small, lead to substantial uncertainties in the final representation of the oxygen isotope ratios. In particular, for the older parts of the NGRIP record, our results show that the total uncertainty originating from dating errors has been seriously underestimated. Our method is next applied to deriving the overall uncertainties of the Suigetsu radiocarbon comparison curve, which was recently obtained from varved sediment cores at Lake Suigetsu, Japan. This curve provides the only terrestrial radiocarbon comparison for the time interval 12.5-52.8 kyr BP. The uncertainties derived here can be readily employed to obtain complete error estimates for arbitrary radiometrically dated proxy records of this recent part of the last glacial interval.}, language = {en} } @phdthesis{Bookhagen2004, author = {Bookhagen, Bodo}, title = {Late quaternary climate changes and landscape evolution in the Northwest Himalaya : geomorphologic processes in the Indian Summer Monsoon Domain}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001956}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {The India-Eurasia continental collision zone provides a spectacular example of active mountain building and climatic forcing. In order to quantify the critically important process of mass removal, I analyzed spatial and temporal precipitation patterns of the oscillating monsoon system and their geomorphic imprints. I processed passive microwave satellite data to derive high-resolution rainfall estimates for the last decade and identified an abnormal monsoon year in 2002. During this year, precipitation migrated far into the Sutlej Valley in the northwestern part of the Himalaya and reached regions behind orographic barriers that are normally arid. There, sediment flux, mean basin denudation rates, and channel-forming processes such as erosion by debris-flows increased significantly. Similarly, during the late Pleistocene and early Holocene, solar forcing increased the strength of the Indian summer monsoon for several millennia and presumably lead to analogous precipitation distribution as were observed during 2002. However, the persistent humid conditions in the steep, high-elevation parts of the Sutlej River resulted in deep-seated landsliding. Landslides were exceptionally large, mainly due to two processes that I infer for this time: At the onset of the intensified monsoon at 9.7 ka BP heavy rainfall and high river discharge removed material stored along the river, and lowered the baselevel. Second, enhanced discharge, sediment flux, and increased pore-water pressures along the hillslopes eventually lead to exceptionally large landslides that have not been observed in other periods. The excess sediments that were removed from the upstream parts of the Sutlej Valley were rapidly deposited in the low-gradient sectors of the lower Sutlej River. Timing of downcutting correlates with centennial-long weaker monsoon periods that were characterized by lower rainfall. I explain this relationship by taking sediment flux and rainfall dynamics into account: High sediment flux derived from the upstream parts of the Sutlej River during strong monsoon phases prevents fluvial incision due to oversaturation the fluvial sediment-transport capacity. In contrast, weaker monsoons result in a lower sediment flux that allows incision in the low-elevation parts of the Sutlej River.}, language = {en} } @article{Buerger2018, author = {B{\"u}rger, Gerd}, title = {A counterexample to decomposing climate shifts and trends by weather types}, series = {International Journal of Climatology}, volume = {38}, journal = {International Journal of Climatology}, number = {9}, publisher = {Wiley}, address = {Hoboken}, issn = {0899-8418}, doi = {10.1002/joc.5519}, pages = {3732 -- 3735}, year = {2018}, abstract = {The literature contains a sizable number of publications where weather types are used to decompose climate shifts or trends into contributions of frequency and mean of those types. They are all based on the product rule, that is, a transformation of a product of sums into a sum of products, the latter providing the decomposition. While there is nothing to argue about the transformation itself, its interpretation as a climate shift or trend decomposition is bound to fail. While the case of a climate shift may be viewed as an incomplete description of a more complex behaviour, trend decomposition indeed produces bogus trends, as demonstrated by a synthetic counterexample with well-defined trends in type frequency and mean. Consequently, decompositions based on that transformation, be it for climate shifts or trends, must not be used.}, language = {en} } @phdthesis{Dahlke2020, author = {Dahlke, Sandro}, title = {Rapid climate changes in the arctic region of Svalbard}, doi = {10.25932/publishup-44554}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445542}, school = {Universit{\"a}t Potsdam}, pages = {xv, 123}, year = {2020}, abstract = {Over the last decades, the Arctic regions of the earth have warmed at a rate 2-3 times faster than the global average- a phenomenon called Arctic Amplification. A complex, non-linear interplay of physical processes and unique pecularities in the Arctic climate system is responsible for this, but the relative role of individual processes remains to be debated. This thesis focuses on the climate change and related processes on Svalbard, an archipelago in the North Atlantic sector of the Arctic, which is shown to be a "hotspot" for the amplified recent warming during winter. In this highly dynamical region, both oceanic and atmospheric large-scale transports of heat and moisture interfere with spatially inhomogenous surface conditions, and the corresponding energy exchange strongly shapes the atmospheric boundary layer. In the first part, Pan-Svalbard gradients in the surface air temperature (SAT) and sea ice extent (SIE) in the fjords are quantified and characterized. This analysis is based on observational data from meteorological stations, operational sea ice charts, and hydrographic observations from the adjacent ocean, which cover the 1980-2016 period. It is revealed that typical estimates of SIE during late winter range from 40-50\% (80-90\%) in the western (eastern) parts of Svalbard. However, strong SAT warming during winter of the order of 2-3K per decade dictates excessive ice loss, leaving fjords in the western parts essentially ice-free in recent winters. It is further demostrated that warm water currents on the west coast of Svalbard, as well as meridional winds contribute to regional differences in the SIE evolution. In particular, the proximity to warm water masses of the West Spitsbergen Current can explain 20-37\% of SIE variability in fjords on west Svalbard, while meridional winds and associated ice drift may regionally explain 20-50\% of SIE variability in the north and northeast. Strong SAT warming has overruled these impacts in recent years, though. In the next part of the analysis, the contribution of large-scale atmospheric circulation changes to the Svalbard temperature development over the last 20 years is investigated. A study employing kinematic air-back trajectories for Ny-{\AA}lesund reveals a shift in the source regions of lower-troposheric air over time for both the winter and the summer season. In winter, air in the recent decade is more often of lower-latitude Atlantic origin, and less frequent of Arctic origin. This affects heat- and moisture advection towards Svalbard, potentially manipulating clouds and longwave downward radiation in that region. A closer investigation indicates that this shift during winter is associated with a strengthened Ural blocking high and Icelandic low, and contributes about 25\% to the observed winter warming on Svalbard over the last 20 years. Conversely, circulation changes during summer include a strengthened Greenland blocking high which leads to more frequent cold air advection from the central Arctic towards Svalbard, and less frequent air mass origins in the lower latitudes of the North Atlantic. Hence, circulation changes during winter are shown to have an amplifying effect on the recent warming on Svalbard, while summer circulation changes tend to mask warming. An observational case study using upper air soundings from the AWIPEV research station in Ny-{\AA}lesund during May-June 2017 underlines that such circulation changes during summer are associated with tropospheric anomalies in temperature, humidity and boundary layer height. In the last part of the analysis, the regional representativeness of the above described changes around Svalbard for the broader Arctic is investigated. Therefore, the terms in the diagnostic temperature equation in the Arctic-wide lower troposphere are examined for the Era-Interim atmospheric reanalysis product. Significant positive trends in diabatic heating rates, consistent with latent heat transfer to the atmosphere over regions of increasing ice melt, are found for all seasons over the Barents/Kara Seas, and in individual months in the vicinity of Svalbard. The above introduced warm (cold) advection trends during winter (summer) on Svalbard are successfully reproduced. Regarding winter, they are regionally confined to the Barents Sea and Fram Strait, between 70°-80°N, resembling a unique feature in the whole Arctic. Summer cold advection trends are confined to the area between eastern Greenland and Franz Josef Land, enclosing Svalbard.}, language = {en} } @phdthesis{Demory2004, author = {Demory, Fran{\c{c}}ois}, title = {Paleomagnetic dating of climatic events in Late Quaternary sediments of Lake Baikal (Siberia)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0001720}, school = {Universit{\"a}t Potsdam}, year = {2004}, abstract = {Der Baikalsee ist ein ideales Klimaarchiv f{\"u}r die Mitte Eurasiens. In dieser Arbeit wurde gesteinsmagnetische und paleomagnetische Analysen an hemipelagischen Sequenzen von vier Lokationen analysiert. Die Kerne erreichen ein Alter von maximal 300 ky. In Kombination mit TEM, XRD, XRF und geochemischen Analysen zeigt die gesteinsmagnetische Studie, dass detritischer Magnetit das magnetische Signal der glazialen Sedimente dominiert. Die magnetischen Signale der interglazialen Sedimente wurden durch diagenetische Prozesse ver{\"a}ndert. Mittels HIRM k{\"o}nnen H{\"a}matit und Goethit quantifiziert werden. Diese Methode eignet sich, den detritischen Eintrag in den Baikalsee abzusch{\"a}tzen. Relative Paleointensit{\"a}ten des Erdmagnetfeldes ergaben reproduizerbare Muster, welche in Korrelation mit gutdatierten Referenzproben die Ableitung eines alternativen Altersmodells f{\"u}r die Datierung der Baikalsedimente erm{\"o}glichten. Bei Anwendung des paleomagnetischen Altersmodells beobachtet man, dass die Abk{\"u}hlung im Baikalgebiet und im Oberfl{\"a}chenwasser des Nordatlantiks wie sie aus den \&\#948;18 O-Werten planktonischer Foraminiferen abgeleitet werden kann, zeitgleich ist. Wird das aus benthischen \&\#948;18 O-Werten abgeleitete Altermdodell auf den Baikalsee angewandt, ergibt sich eine deutliche Zeitverschiebung. Das benthische Altersmodell repr{\"a}sentiert die globale Ver{\"a}nderung des Eisvolumens, welche sp{\"a}ter als die V{\"a}nderung der Oberfl{\"a}chenwassertemperatur auftritt. Die Kompilation paleomagnetischer Kurven ergab eine neue relative Paleointensit{\"a}tskurve \“Baikal 200\”. Mittels Korngr{\"o}ssenanalyse des Detritus konnten drei Faziestypen mit unterschiedlicher Sedimentationsdynamik unterschieden werden: 1) Glaziale Peroiden werden durch hohe Tongehalte infolge von Windeintrag und durch grobe Sandfraktion mittels Transport durch lokale Winde {\"u}ber das Eis charakterisiert. Dieser Faziestyp deutet auf arides Klima. 2) W{\"a}hrend der Glazial/Interglazial-{\"U}berg{\"a}nge steigt die Siltfraktion an. Dies deutet auf erh{\"o}hte Feuchtigkeit und damit verbunden erh{\"o}hte Sedimentdynamik. Windtransport und in den Schnee der Eisdecke eingetragener Staub sind die vorherrschenden Prozesse, welche den Silt in hemipelagischer Position zur Ablagerung bringen. 3) W{\"a}hrend des klimatischen Optimum des Eeemian werden Gr{\"o}sse und Quantit{\"a}t des Silts minimal, was auf eine geschlossene Vegetationsdecke im Hinterland deutet.}, language = {en} } @misc{EgholmAndersenFaurschouKnudsenetal.2015, author = {Egholm, David L. and Andersen, Jane Lund and Faurschou Knudsen, Mads and Jansen, John D. and Nielsen, S. B.}, title = {The periglacial engine of mountain erosion}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {552}, issn = {1866-8372}, doi = {10.25932/publishup-40971}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-409718}, pages = {20}, year = {2015}, abstract = {There is growing recognition of strong periglacial control on bedrock erosion in mountain landscapes, including the shaping of low-relief surfaces at high elevations (summit flats). But, as yet, the hypothesis that frost action was crucial to the assumed Late Cenozoic rise in erosion rates remains compelling and untested. Here we present a landscape evolution model incorporating two key periglacial processes - regolith production via frost cracking and sediment transport via frost creep - which together are harnessed to variations in temperature and the evolving thickness of sediment cover. Our computational experiments time-integrate the contribution of frost action to shaping mountain topography over million-year timescales, with the primary and highly reproducible outcome being the development of flattish or gently convex summit flats. A simple scaling of temperature to marine delta O-18 records spanning the past 14 Myr indicates that the highest summit flats in mid-to high-latitude mountains may have formed via frost action prior to the Quaternary. We suggest that deep cooling in the Quaternary accelerated mechanical weathering globally by significantly expanding the area subject to frost. Further, the inclusion of subglacial erosion alongside periglacial processes in our computational experiments points to alpine glaciers increasing the long-term efficiency of frost-driven erosion by steepening hillslopes.}, language = {en} } @misc{FeldmannLevermann2017, author = {Feldmann, Johannes and Levermann, Anders}, title = {From cyclic ice streaming to Heinrich-like events}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {652}, issn = {1866-8372}, doi = {10.25932/publishup-41877}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418777}, pages = {20}, year = {2017}, abstract = {Here we report on a cyclic, physical ice-discharge instability in the Parallel Ice Sheet Model, simulating the flow of a three-dimensional, inherently buttressed ice-sheet-shelf system which periodically surges on a millennial timescale. The thermomechanically coupled model on 1 km horizontal resolution includes an enthalpy-based formulation of the thermodynamics, a nonlinear stress-balance-based sliding law and a very simple subglacial hydrology. The simulated unforced surging is characterized by rapid ice streaming through a bed trough, resulting in abrupt discharge of ice across the grounding line which is eventually calved into the ocean. We visualize the central feedbacks that dominate the subsequent phases of ice buildup, surge and stabilization which emerge from the interaction between ice dynamics, thermodynamics and the subglacial till layer. Results from the variation of surface mass balance and basal roughness suggest that ice sheets of medium thickness may be more susceptible to surging than relatively thin or thick ones for which the surge feedback loop is damped. We also investigate the influence of different basal sliding laws (ranging from purely plastic to nonlinear to linear) on possible surging. The presented mechanisms underlying our simulations of self-maintained, periodic ice growth and destabilization may play a role in large-scale ice-sheet surging, such as the surging of the Laurentide Ice Sheet, which is associated with Heinrich events, and ice-stream shutdown and reactivation, such as observed in the Siple Coast region of West Antarctica.}, language = {en} } @article{ForteWhippleBookhagenetal.2016, author = {Forte, Adam M. and Whipple, Kelin X. and Bookhagen, Bodo and Rossi, Matthew W.}, title = {Decoupling of modern shortening rates, climate, and topography in the Caucasus}, series = {Earth \& planetary science letters}, volume = {449}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2016.06.013}, pages = {282 -- 294}, year = {2016}, abstract = {The Greater and Lesser Caucasus mountains and their associated foreland basins contain similar rock types, experience a similar two-fold, along-strike variation in mean annual precipitation, and were affected by extreme base-level drops of the neighboring Caspian Sea. However, the two Caucasus ranges are characterized by decidedly different tectonic regimes and rates of deformation that are subject to moderate (less than an order of magnitude) gradients in climate, and thus allow for a unique opportunity to isolate the effects of climate and tectonics in the evolution of topography within active orogens. There is an apparent disconnect between modern climate, shortening rates, and topography of both the Greater Caucasus and Lesser Caucasus which exhibit remarkably similar topography along-strike despite the gradients in forcing. By combining multiple datasets, we examine plausible causes for this disconnect by presenting a detailed analysis of the topography of both ranges utilizing established relationships between catchment-mean erosion rates and topography (local relief, hillslope gradients, and channel steepness) and combining it with a synthesis of previously published low-temperature thermochronologic data. Modern climate of the Caucasus region is assessed through an analysis of remotely-sensed data (TRMM and MODIS) and historical streamflow data. Because along-strike variation in either erosional efficiency or thickness of accreted material fail to explain our observations, we suggest that the topography of both the western Lesser and Greater Caucasus are partially supported by different geodynamic forces. In the western Lesser Caucasus, high relief portions of the landscape likely reflect uplift related to ongoing mantle lithosphere delamination beneath the neighboring East Anatolian Plateau. In the Greater Caucasus, maintenance of high topography in the western portion of the range despite extremely low (<2-4 mm/y) modern convergence rates may be related to dynamic topography from detachment of the north-directed Greater Caucasus slab or to a recent slowing of convergence rates. Large-scale spatial gradients in climate are not reflected in the topography of the Caucasus and do not seem to exert any significant control on the tectonics or structure of either range. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{Fuhr2012, author = {Fuhr, Harald}, title = {Klimawandel und Entwicklungspolitik}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81301}, pages = {31 -- 40}, year = {2012}, abstract = {Der Autor diskutiert die Chancen und Risiken bei der Einbindung des S{\"u}dens in die internationale Klimapolitik. Lange Zeit hatten die Entwicklungsl{\"a}nder am wenigsten zum Klimawandel beigetragen, w{\"a}ren aber am st{\"a}rksten von ihm betroffen. Mittlerweile jedoch tragen diese L{\"a}nder in erheblichem Maße selbst zum Klimawandel bei. Allerdings setzen deren Regierungen auf Zeit. Sie erwarten Ressourcentransfers. Dies verst{\"a}rkt auch alte Probleme des ‚Rent-Seeking'.}, language = {de} } @article{GanguliPaprotnyHasanetal.2020, author = {Ganguli, Poulomi and Paprotny, Dominik and Hasan, Mehedi and G{\"u}ntner, Andreas and Merz, Bruno}, title = {Projected changes in compound flood hazard from riverine and coastal floods in northwestern Europe}, series = {Earth's future}, volume = {8}, journal = {Earth's future}, number = {11}, publisher = {Wiley-Blackwell}, address = {Hoboken, NJ}, issn = {2328-4277}, doi = {10.1029/2020EF001752}, pages = {19}, year = {2020}, abstract = {Compound flooding in coastal regions, that is, the simultaneous or successive occurrence of high sea levels and high river flows, is expected to increase in a warmer world. To date, however, there is no robust evidence on projected changes in compound flooding for northwestern Europe. We combine projected storm surges and river floods with probabilistic, localized relative sea-level rise (SLR) scenarios to assess the future compound flood hazard over northwestern coastal Europe in the high (RCP8.5) emission scenario. We use high-resolution, dynamically downscaled regional climate models (RCM) to drive a storm surge model and a hydrological model, and analyze the joint occurrence of high coastal water levels and associated river peaks in a multivariate copula-based approach. The RCM-forced multimodel mean reasonably represents the observed spatial pattern of the dependence strength between annual maxima surge and peak river discharge, although substantial discrepancies exist between observed and simulated dependence strength. All models overestimate the dependence strength, possibly due to limitations in model parameterizations. This bias affects compound flood hazard estimates and requires further investigation. While our results suggest decreasing compound flood hazard over the majority of sites by 2050s (2040-2069) compared to the reference period (1985-2005), an increase in projected compound flood hazard is limited to around 34\% of the sites. Further, we show the substantial role of SLR, a driver of compound floods, which has frequently been neglected. Our findings highlight the need to be aware of the limitations of the current generation of Earth system models in simulating coastal compound floods.}, language = {en} } @article{GoldGronewoldSalterio2014, author = {Gold, Anna and Gronewold, Ulfert and Salterio, Steven E.}, title = {Error management in audit firms: error climate, type, and originator}, series = {The accounting review : a journal of the American Accounting Association}, volume = {89}, journal = {The accounting review : a journal of the American Accounting Association}, number = {1}, publisher = {American Accounting Association}, address = {Sarasota}, issn = {0001-4826}, doi = {10.2308/accr-50592}, pages = {303 -- 330}, year = {2014}, language = {en} } @article{HanRydinBolinderetal.2016, author = {Han, Fang and Rydin, Catarina and Bolinder, Kristina and Dupont-Nivet, Guillaume and Abels, Hemmo A. and Koutsodendris, Andreas and Zhang, Kexin and Hoorn, Carina}, title = {Steppe development on the Northern Tibetan Plateau inferred from Paleogene ephedroid pollen}, series = {Grana}, volume = {55}, journal = {Grana}, publisher = {Springer}, address = {Oslo}, issn = {0017-3134}, doi = {10.1080/00173134.2015.1120343}, pages = {71 -- 100}, year = {2016}, abstract = {Steppe vegetation represents a key marker of past Asian aridification and is associated with monsoonal intensification. Little is, however, known about the origin of this pre-Oligocene vegetation, its specific composition and how it changed over time and responded to climatic variations. Here, we describe the morphological characters of Ephedraceae pollen in Eocene strata of the Xining Basin and compare the pollen composition with the palynological composition of Late Cretaceous and Paleocene deposits of the Xining Basin and the Quaternary deposits of the Qaidam Basin. We find that the Late Cretaceous steppe was dominated by Gnetaceaepollenites; in the transition from the Cretaceous to the Paleocene, Gnetaceaepollenites became extinct and Ephedripites subgenus Ephedripites dominated the flora with rare occurrences of Ephedripites subgen. Distachyapites; the middle to late Eocene presents a strong increase of Ephedripites subgen. Distachyapites; and the Quaternary/Recent is marked by a significantly lower diversity of Ephedraceae (and Nitrariaceae) compared to the Eocene. In the modern landscape of China, only a fraction of the Paleogene species diversity of Ephedraceae remains and we propose that these alterations in Ephedreaceae composition occurred in response to the climatic changes at least since the Eocene. In particular, the strong Eocene monsoons that enhanced the continental aridification may have played an important role in the evolution of Ephedripites subgen. Distachyapites triggering an evolutionary shift to wind-pollination in this group. Conceivably, the Ephedraceae/Nitrariaceae dominated steppe ended during the Eocene/Oligocene climatic cooling and aridification, which favoured other plant taxa.}, language = {en} } @phdthesis{Hanschmann2019, author = {Hanschmann, Raffael Tino}, title = {Stalling the engine? EU climate politics after the 'Great Recession'}, doi = {10.25932/publishup-44044}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440441}, school = {Universit{\"a}t Potsdam}, pages = {XXVIII, 303}, year = {2019}, abstract = {This dissertation investigates the impact of the economic and fiscal crisis starting in 2008 on EU climate policy-making. While the overall number of adopted greenhouse gas emission reduction policies declined in the crisis aftermath, EU lawmakers decided to introduce new or tighten existing regulations in some important policy domains. Existing knowledge about the crisis impact on EU legislative decision-making cannot explain these inconsistencies. In response, this study develops an actor-centred conceptual framework based on rational choice institutionalism that provides a micro-level link to explain how economic crises translate into altered policy-making patterns. The core theoretical argument draws on redistributive conflicts, arguing that tensions between 'beneficiaries' and 'losers' of a regulatory initiative intensify during economic crises and spill over to the policy domain. To test this hypothesis and using social network analysis, this study analyses policy processes in three case studies: The introduction of carbon dioxide emission limits for passenger cars, the expansion of the EU Emissions Trading System to aviation, and the introduction of a regulatory framework for biofuels. The key finding is that an economic shock causes EU policy domains to polarise politically, resulting in intensified conflict and more difficult decision-making. The results also show that this process of political polarisation roots in the industry that is the subject of the regulation, and that intergovernmental bargaining among member states becomes more important, but also more difficult in times of crisis.}, language = {en} } @article{HarnischWienges2012, author = {Harnisch, Astrid and Wienges, Sebastian}, title = {Wie Klimaschutz finanzieren?}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81328}, pages = {50 -- 58}, year = {2012}, abstract = {Zur Finanzierung von Klimaschutz m{\"u}ssen {\"o}ffentliche Mittel gezielt eingesetzt werden. Dies beinhaltet auch die Rahmenbedingungen f{\"u}r private Finanzstr{\"o}me signifikant zu verbessern. Anhand einer Problemanalyse bestimmen die Autoren Eckdaten f{\"u}r diese Hebelwirkung. {\"O}ffentliche Anschubfinanzierung kann somit die Grundlage f{\"u}r private Investitionen sein. Dies wird exemplarisch an der Internationalen Klimaschutzinitiative des Bundesumweltministeriums diskutiert.}, language = {de} } @article{HaugBerkhout2012, author = {Haug, Constanze and Berkhout, Frans}, title = {Abschied von KyotoPlus?}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81355}, pages = {73 -- 81}, year = {2012}, abstract = {Die Ergebnisse des Klimagipfels von Kopenhagen sind eine bittere Entt{\"a}uschung f{\"u}r die EU. Ihr ist es nicht gelungen, ihren F{\"u}hrungsambitionen beim globalen Klimaschutz gerecht zu werden und die Konferenz zur Weichenstellung f{\"u}r ein rechtsverbindliches Klimaabkommen nach 2012 zu nutzen. Damit steht die Union vor grundlegenden strategischen Fragen zum Kurs ihrer Klimapolitik.}, language = {de} } @article{HeidarzadehBallatoHassanzadehetal.2017, author = {Heidarzadeh, Ghasem and Ballato, Paolo and Hassanzadeh, Jamshid and Ghassemi, Mohammad R. and Strecker, Manfred}, title = {Lake overspill and onset of fluvial incision in the Iranian Plateau: Insights from the Mianeh Basin}, series = {Earth \& planetary science letters}, volume = {469}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2017.04.019}, pages = {135 -- 147}, year = {2017}, abstract = {Orogenic plateaus represent a prime example of the interplay between surface processes, climate, and tectonics. This kind of an interplay is thought to be responsible for the formation, preservation, and, ultimately, the destruction of a typical elevated, low-internal relief plateau landscape. Here, we document the timing of intermontane basin filling associated with the formation of a low-relief plateau morphology, followed by basin opening and plateau-flank incision in the northwestern Iranian Plateau of the Arabia Eurasia collision zone. Our new U-Pb zircon ages from intercalated volcanic ashes in exposed plateau basin-fill sediments from the most external plateau basin (Mianeh Basin) document that the basin was internally drained at least between similar to 7 and 4 Ma, and that from similar to 5 to 4 Ma it was characterized by an similar to 2-km-high and similar to 0.5-km-deep lake (Mianeh paleolake), most likely as a result of wetter climatic conditions. At the same time, the eastern margin of the Mianeh Basin (and, therefore, of the Iranian Plateau) experienced limited tectonic activity, as documented by onlapping sediments and smoothed topography. The combination of high lake level and subdued topography at the plateau margin led to lake overspill, which resulted in the cutting of an similar to 1-km-deep bedrock gorge (Amardos) by the Qezel-Owzan River (QOR) beginning at similar to 4 Ma. This was associated with the incision of the plateau landscape and the establishment of fluvial connectivity with the Caspian Sea. Overall, our study emphasizes the interplay between surface and tectonic processes in forming, maintaining, and destroying orogenic plateau morphology, the transitional nature of orogenic plateau landscapes on timescales of 10(6) yr, and, finally, the role played by overspilling in integrating endorheic basins. (C) 2017 Elsevier B.V. All rights reserved.}, language = {en} } @article{Hentschel2012, author = {Hentschel, Karl-Martin}, title = {Klimapolitik am Ende?}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81299}, pages = {21 -- 30}, year = {2012}, language = {de} } @article{HierroBurgosFonsecaRamezaniZiaranietal.2019, author = {Hierro, Rodrigo and Burgos Fonseca, Y. and Ramezani Ziarani, Maryam and Llamedo, P. and Schmidt, Torsten and de la Torre, Alejandro and Alexander, P.}, title = {On the behavior of rainfall maxima at the eastern Andes}, series = {Atmospheric Research}, volume = {234}, journal = {Atmospheric Research}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, issn = {0169-8095}, doi = {10.1016/j.atmosres.2019.104792}, year = {2019}, abstract = {In this study, we detect high percentile rainfall events in the eastern central Andes, based on Tropical Rainfall Measuring Mission (TRMM) with a spatial resolution of 0.25 × 0.25°, a temporal resolution of 3 h, and for the duration from 2001 to 2018. We identify three areas with high mean accumulated rainfall and analyze their atmospheric behaviour and rainfall characteristics with specific focus on extreme events. Extreme events are defined by events above the 95th percentile of their daily mean accumulated rainfall. Austral summer (DJF) is the period of the year presenting the most frequent extreme events over these three regions. Daily statistics show that the spatial maxima, as well as their associated extreme events, are produced during the night. For the considered period, ERA-Interim reanalysis data, provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) with 0.75° x0.75° spatial and 6-hourly temporal resolutions, were used for the analysis of the meso- and synoptic-scale atmospheric patterns. Night- and day-time differences indicate a nocturnal overload of northerly and northeasterly low-level humidity flows arriving from tropical South America. Under these conditions, cooling descending air from the mountains may find unstable air at the surface, giving place to the development of strong local convection. Another possible mechanism is presented here: a forced ascent of the low-level flow due to the mountains, disrupting the atmospheric stratification and generating vertical displacement of air trajectories. A Principal Component Analysis (PCA) in T-mode is applied to day- and night-time data during the maximum and extreme events. The results show strong correlation areas over each subregion under study during night-time, whereas during day-time no defined patterns are found. This confirms the observed nocturnal behavior of rainfall within these three hotspots.}, language = {en} } @article{HortonKhanCahilletal.2020, author = {Horton, Benjamin P. and Khan, Nicole S. and Cahill, Niamh and Lee, Janice S. H. and Shaw, Timothy A. and Garner, Andra J. and Kemp, Andrew C. and Engelhart, Simon E. and Rahmstorf, Stefan}, title = {Estimating global mean sea-level rise and its uncertainties by 2100 and 2300 from an expert survey}, series = {npj Climate and Atmospheric Science}, volume = {3}, journal = {npj Climate and Atmospheric Science}, number = {1}, publisher = {Springer Nature}, address = {London}, issn = {2397-3722}, doi = {10.1038/s41612-020-0121-5}, pages = {1 -- 8}, year = {2020}, abstract = {Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66\% probability) GMSL rise of 0.30-0.65 m by 2100, and 0.54-2.15 m by 2300, relative to 1986-2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63-1.32 m by 2100, and 1.67-5.61 m by 2300. Expert projections for 2100 are similar to those from the original survey, although the projection for 2300 has extended tails and is higher than the original survey. Experts give a likelihood of 42\% (original survey) and 45\% (current survey) that under the high-emissions scenario GMSL rise will exceed the upper bound (0.98 m) of the likely range estimated by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, which is considered to have an exceedance likelihood of 17\%. Responses to open-ended questions suggest that the increases in upper-end estimates and uncertainties arose from recent influential studies about the impact of marine ice cliff instability on the meltwater contribution to GMSL rise from the Antarctic Ice Sheet.}, language = {en} } @misc{HortonKhanCahilletal.2020, author = {Horton, Benjamin P. and Khan, Nicole S. and Cahill, Niamh and Lee, Janice S. H. and Shaw, Timothy A. and Garner, Andra J. and Kemp, Andrew C. and Engelhart, Simon E. and Rahmstorf, Stefan}, title = {Estimating global mean sea-level rise and its uncertainties by 2100 and 2300 from an expert survey}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-51678}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-516788}, pages = {10}, year = {2020}, abstract = {Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66\% probability) GMSL rise of 0.30-0.65 m by 2100, and 0.54-2.15 m by 2300, relative to 1986-2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63-1.32 m by 2100, and 1.67-5.61 m by 2300. Expert projections for 2100 are similar to those from the original survey, although the projection for 2300 has extended tails and is higher than the original survey. Experts give a likelihood of 42\% (original survey) and 45\% (current survey) that under the high-emissions scenario GMSL rise will exceed the upper bound (0.98 m) of the likely range estimated by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, which is considered to have an exceedance likelihood of 17\%. Responses to open-ended questions suggest that the increases in upper-end estimates and uncertainties arose from recent influential studies about the impact of marine ice cliff instability on the meltwater contribution to GMSL rise from the Antarctic Ice Sheet.}, language = {en} } @phdthesis{JimenezAlvaro2023, author = {Jim{\´e}nez {\´A}lvaro, Eliana}, title = {An{\´a}lisis neotect{\´o}nico y lito-tefroestratigr{\´a}fico de los grandes movimientos en masa asociados al fallamiento activo de la cuenca intermontana Quito-Guayllabamba, Ecuador}, doi = {10.25932/publishup-62220}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-622209}, school = {Universit{\"a}t Potsdam}, pages = {195}, year = {2023}, abstract = {Within the Quito-Guayllabamba intermontane basin of Ecuador, five unusually large colluvial deposits of ancient landslides have been identified and analyzed in this study. The voluminous rotational MM-5 Guayllabamba landslide is the largest one, with a volume of 1183 million m3. The mega debris-avalanches MM-1 Conocoto, MM-3 Oyacoto, and MM-4 San Francisco were originally triggered by an initial rupture that was associated with a rotational landslide, the corresponding deposits have volumes between 399 to 317 million m3. Finally, the deposit with the smallest volume, the MM-2 Bat{\´a}n rotational landslide and debris fall, has a volume of 8,7 million m3. In this thesis, a detailed study of these large mass movements was carried out using neotectonic and litho-tephrostratigraphic methods to understand the geological and geomorphological boundary conditions that might have been relevant for triggering such mass movements. The neotectonic part of the study was based on the qualitative and quantitative geomorphic analysis of these large mass-movement deposits through the structural characterization of anticlines located east of the Quito sub-basin and their collapsed flanks that constitute the break-off areas. This part of the analysis was furthermore supported by the application of different morphometric indices to reveal tectonically forced landscape evolution processes that may have aided mass-movement generation. The litho-tephrostratigraphic part of the study was based on the analysis of petrographic, geochemical, and geochronological characteristics of soil horizons and intercalated volcanic ashes with the aim to constrain the timing of individual mass-movement events and their potential correlation. The results were integrated into chronostratigraphic schemes using break-off surfaces, cross-cutting and superposition relationships of landslide deposits and subsequently deposited strata to understand the mass movements in the tectonic and temporal context of the intermontane basin setting, as well as to identify the triggering mechanisms for each event. The MM-5 Guayllabamba mass movement is the result of the collapse of the southwestern slope of the Mojanda volcano and was triggered by the interaction of geologic and morphologic conditions approximately 0,81 Ma. The first debris-avalanche episode of the MM-3 Oyacoto and MM-4 San Francisco mass movements could be related to both geological and morphological conditions, given the highly fractured rocks and uplift of the Bellavista-Catequilla anticline that was subsequently incised at the foot of the slope by fluvial erosion. This first episode of collapse most likely occurred around 0,8 Ma. The MM-2 Bat{\´a}n mass movement was possibly also facilitated by a combination of geological and morphological conditions, most likely associated with a reduction in the lithostatic stresses affecting the Chiche and Mach{\´a}ngara formations and an increase of shear stresses during lateral fluvial scouring processes at the flanks of the source areas. This points to a linked process between river erosion and uplift processes associated with the evolution of the El Bat{\´a}n-La Bota anticline that could have occurred between 0,5 and 0,25 Ma. The voluminous MM-1 Conocoto debris avalanche, as well as the second debris avalanche episode that generated the MM-3 Oyacoto and MM-4 San Francisco mass movements, were caused by the gravitational collapse of the Mojanda and Cangahua formations that are characterized by the intercalation of volcanic ashes. The failure of the eastern flank of the anticlines probably was associated with increased available humidity related to regional Holocene climatic variations. The results of paleosol chronology combined with regional chronostratigraphic and paleoclimate data suggests that these debris avalanches were triggered between 5 and 4 ka. Active tectonics has shaped the morphological features of the Quito-Guayllabamba intermontane basin. The triggering of mass movements in this environment is associated with failure of Pleistocene lithologies (lake sediments, alluvial and volcanic deposits) subjected to ongoing deformation processes, seismic activity, and superposed episodes of climate variability. The Metropolitan District of Quito is an integral part of this complex environment and the geological, climatic, and topographic conditions that continue to influence the urban geographic space within this intermontane basin. The city of Quito comprises the area with the largest urban consolidation including the sub-basins of Quito and San Antonio, with a population of 2,872 million inhabitants, reflecting the importance of studying the inherent geological and climatic hazards that this region is confronted with.}, language = {es} } @phdthesis{John2003, author = {John, C{\´e}dric Micha{\"e}l}, title = {Miocene climate as recorded on slope carbonates : examples from Malta (Central Mediterranean) and Northeastern Australia (Marion Plateau, ODP LEG 194)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-0000820}, school = {Universit{\"a}t Potsdam}, year = {2003}, abstract = {Im Rahmen dieser Doktorarbeit wurden die Hangkarbonate von zwei mioz{\"a}nen heterozoischen Karbonatsystemen n{\"a}her untersucht: die Malta Inselgruppe (zentrales Mittelmeer) und das Marion Plateau (Nordost Australien, ODP Leg 194). Die Auswirkungen der mittelmioz{\"a}nen Abk{\"u}hlung (Mi3), die auf 13.6 Ma datiert wird und starken Einfluß auf die Sauerstoffisotopenkurve hatte, in den oben genannten Flachwassersystemen stellten das Ziel dieser Arbeit dar. Dieses Abk{\"u}hlungsereignis beeinflußte außerdem sehr stark die ozeanographischen und klimatischen Muster, die im weiteren Verlauf zum modernen Eishausklima f{\"u}hrten. So steht insbesondere die Vereisung von Ostantarktika mit diesem Ereignis in Verbindung. Diese Arbeit untersucht den Einfluß dieses Ereignisses auf Flachwassersysteme, um vorliegende Untersuchungen in Tiefwassersystemen zu erg{\"a}nzen und so zum globalen Verst{\"a}ndnis des mioz{\"a}nen Klimawechsels beizutragen. Die Profile auf der Maltainselgruppe wurden mit Hilfe von Kohlenstoff- und Sauerstoffisotopen Auswertungen im Gesamtgestein, Gesamtgesteinmineralogie, Tonmineralanalyse und organischer Geochemie untersucht. Durch einen Wechsel von karbonatischeren zu tonigeren Sedimenten beeinflußte das mittelmioz{\"a}ne Abk{\"u}hlungsereignis die Sedimentation in diesem Gebiet sehr stark. Weiterhin wurde beobachtet, daß jede Phase der antarktischen Vereisung, nicht nur das mittelmioz{\"a}ne Hauptereignis, zu einem erh{\"o}hten terrigenen Eintrag in den Hangsedimenten der Maltainselgruppe f{\"u}hrte. Akkumulationsraten zeigen, daß dieser erh{\"o}hte terrigene Eintrag den einzelnen Vereisungsperioden zusammenh{\"a}ngt und die karbonatischen Sedimente durch tonreiche Sedimente \“verunreinigt\” wurden. Das daraufhin entwickelte Modell erkl{\"a}rt diesen erh{\"o}hten terrigenen Eintrag mit einer nordw{\"a}rtigen Verlagerung der innertropischen Konvergenzzone durch die Bildung von kalten, dichten Luftmassen, die zu verst{\"a}rkten Niederschl{\"a}gen in Nordafrika f{\"u}hrten. Diese verst{\"a}rkten Niederschl{\"a}ge (oder verst{\"a}rkter afrikanischer Monsun) beeinflußten die kontinentale Verwitterung und den Eintrag, mit der Folge, daß verst{\"a}rkt terrigene Sedimente im Bereich der Hangsedimente der Maltainselgruppe abgelagert wurden. Die tonreichen Intervalle weisen {\"A}hnlichkeiten zu sapropelischen Ablagerungen auf, was mit Hilfe der Spektral analyse des Karbonatgehalts und der geochemischen Analyse des organischen Materials gezeigt wurde. Auf dem Marion Plateau wurden die Sauerstoff- und Kohlenstoffisotopenkurven anhand von Foraminiferen der Gattung Cibicidoides spp. rekonstruiert. Der Karbonatgehalt wurde mit Hilfe einer chemischen Methode (Coulometer) ermittelt. Genauso wie die Sedimente der Maltainselgruppe beeinflußte das mittelmioz{\"a}ne Abk{\"u}hlungsereignis (Mi3) auch die Sedimente auf dem Marion Plateau. So kam es bei 13,8 Ma, in etwa zur Zeit der Vereisung von Ostantarktika, zu einem Abfall der Karbonatakkumulationsraten. Weiterhin traten {\"A}nderungen in der Zusammensetzung der Sedimente auf, so nehmen neritische Karbonatfragmente ab, der planktische Foraminiferengehalt nimmt zu und es wurden verst{\"a}rkt Quarz und Glaukonit abgelagert. Ein {\"u}berraschendes Ergebnis ist die Tatsache, daß der große N12-N14 Meeresspiegelabfall um 11,5 Ma die Akkumulationsraten der Karbonate auf dem Hang nicht beeinflußte. Dieses Ergebnis ist umso erstaunlicher, da Karbonatplattformen normalerweise sehr sensitiv auf Meeresspiegel{\"a}nderungen reagieren. Der Grund, warum sich die Karbonatakkumulationsraten schon um 13,6 Ma (Mi3) und nicht erst um 11,5 Ma (N12-N14) verringerten, liegt in der Tatsache, daß die ozeanischen Str{\"o}mungen die Karbonatsedimentation auf dem Hang des Marion Plateau schon im Mioz{\"a}n kontrollierten. Das mittelmioz{\"a}ne Ereignis (Mi3) erh{\"o}hte die St{\"a}rke diese Str{\"o}mungen und als eine Ursache wurde die Karbonatakkumulation auf den H{\"a}ngen reduziert. Die Amplitude des N12-N14 Meeresspiegelabfalls liegt bei 90 m unter der Ber{\"u}cksichtigung der Sauerstoffisotopendaten aus der Tiefsee und Berechnungen des Meeresspiegels anhand des \“coastal onlaps\”, die w{\"a}hrend Leg 194 gemacht wurden. Die Isotopendaten dieser Arbeit weisen hingegen auf einen verringerten Meeresspiegelabfall von 70 m hin. Als allgemeine Schlußfolgerung kann gesagt werden, daß der mittelmioz{\"a}ne Klimaumschwung die Karbonatsysteme zumindest an den beiden untersuchten Lokalit{\"a}ten beeinflußt hat. Allerdings waren die Auswirkungen sehr von den unterschiedlichen lokalen Gegebenheiten abh{\"a}ngig. Insbesondere wirkten sich die Anwesenheit einer Landmasse (Malta) und die Abwesenheit einer Barriere vor den Einfl{\"u}ssen des offenen Ozeans (Marion Plateau) stark auf die Ablagerung der Karbonate aus.}, language = {en} } @article{JuangSchachnerAraletal.2023, author = {Juang, Linda P. and Schachner, Maja and Aral, Tuğ{\c{c}}e and Schwarzenthal, Miriam and Kunyu, David Khisoni and L{\"o}hmannsr{\"o}ben, Hanna}, title = {Effects of a brief self-affirmation writing intervention among 7(th) graders in Germany}, series = {Social psychology of education : an international journal}, journal = {Social psychology of education : an international journal}, publisher = {Springer}, address = {Dordrecht}, issn = {1381-2890}, doi = {10.1007/s11218-023-09789-9}, pages = {35}, year = {2023}, abstract = {We tested whether a brief self-affirmation writing intervention protected against identity-threats (i.e., stereotyping and discrimination) for adolescents' school-related adjustment. The longitudinal study followed 639 adolescents in Germany (65\% of immigrant descent, 50\% female, M-age = 12.35 years, SDage = .69) from 7(th) grade (pre-intervention at T1, five to six months post-intervention at T2) to the end of 8(th) grade (one-year follow-up at T3). We tested for direct and moderated (by heritage group, discrimination, classroom cultural diversity climate) effects using regression and latent change models. The self-affirmation intervention did not promote grades or math competence. However, in the short-term and for adolescents of immigrant descent, the intervention prevented a downward trajectory in mastery reactions to academic challenges for those experiencing greater discrimination. Further, it protected against a decline in behavioral school engagement for those in positive classroom cultural diversity climates. In the long-term and for all adolescents, the intervention lessened an upward trajectory in disruptive behavior. Overall, the self-affirmation intervention benefited some aspects of school-related adjustment for adolescents of immigrant and non-immigrant descent. The intervention context is important, with classroom cultural diversity climate acting as a psychological affordance enhancing affirmation effects. Our study supports the ongoing call for theorizing and empirically testing student and context heterogeneity to better understand for whom and under which conditions this intervention may work.}, language = {en} } @article{KalkuhlSchwerhoffWaha2020, author = {Kalkuhl, Matthias and Schwerhoff, Gregor and Waha, Katharina}, title = {Land tenure, climate and risk management}, series = {Ecological economics}, volume = {171}, journal = {Ecological economics}, publisher = {Elsevier Science}, address = {Amsterdam [u.a.]}, issn = {0921-8009}, doi = {10.1016/j.ecolecon.2019.106573}, pages = {16}, year = {2020}, abstract = {We analyze to what extent climate conditions affect the prevalence of sharecropping as a form of traditional land tenure. We investigate how sharecropping tenure is related to climate risk and how it interacts with fertilizer use and livestock ownership that both influence production risk. We first develop a stylized theoretical model to illustrate the role of climate for land tenure and production. Our empirical analysis is based on more than 9000 households with considerable heterogeneity in climate conditions across several African countries. We find that farmers in areas with low precipitation are more likely to be sharecroppers. We further find evidence for risk management interaction effects as sharecropping farmers are less likely to own livestock and more likely to use fertilizer. In economies where formal kinds of insurance are unavailable, sharecropping thus functions as a form of insurance and reduces the need for potentially costly risk management strategies.}, language = {en} } @article{KayaDupontNivetProustetal.2019, author = {Kaya, Mustafa Y{\"u}cel and Dupont-Nivet, Guillaume and Proust, Jean-No{\"e}l and Roperch, Pierrick and Bougeois, Laurie and Meijer, Niels and Frieling, Joost and Fioroni, Chiara and Altiner, Sevin{\c{c}} {\"O}zkan and Vardar, Ezgi and Barbolini, Natasha and Stoica, Marius and Aminov, Jovid and Mamtimin, Mehmut and Zhaojie, Guo}, title = {Paleogene evolution and demise of the proto-Paratethys Sea in Central Asia (Tarim and Tajik basins)}, series = {Basin research}, volume = {31}, journal = {Basin research}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {0950-091X}, doi = {10.1111/bre.12330}, pages = {461 -- 486}, year = {2019}, abstract = {The proto-Paratethys Sea covered a vast area extending from the Mediterranean Tethys to the Tarim Basin in western China during Cretaceous and early Paleogene. Climate modelling and proxy studies suggest that Asian aridification has been governed by westerly moisture modulated by fluctuations of the proto-Paratethys Sea. Transgressive and regressive episodes of the proto-Paratethys Sea have been previously recognized but their timing, extent and depositional environments remain poorly constrained. This hampers understanding of their driving mechanisms (tectonic and/or eustatic) and their contribution to Asian aridification. Here, we present a new chronostratigraphic framework based on biostratigraphy and magnetostratigraphy as well as a detailed palaeoenvironmental analysis for the Paleogene proto-Paratethys Sea incursions in the Tajik and Tarim basins. This enables us to identify the major drivers of marine fluctuations and their potential consequences on Asian aridification. A major regional restriction event, marked by the exceptionally thick (<= 400 m) shelf evaporites is assigned a Danian-Selandian age (ca. 63-59 Ma) in the Aertashi Formation. This is followed by the largest recorded proto-Paratethys Sea incursion with a transgression estimated as early Thanetian (ca. 59-57 Ma) and a regression within the Ypresian (ca. 53-52 Ma), both within the Qimugen Formation. The transgression of the next incursion in the Kalatar and Wulagen formations is now constrained as early Lutetian (ca. 47-46 Ma), whereas its regression in the Bashibulake Formation is constrained as late Lutetian (ca. 41 Ma) and is associated with a drastic increase in both tectonic subsidence and basin infilling. The age of the final and least pronounced sea incursion restricted to the westernmost margin of the Tarim Basin is assigned as Bartonian-Priabonian (ca. 39.7-36.7 Ma). We interpret the long-term westward retreat of the proto-Paratethys Sea starting at ca. 41 Ma to be associated with far-field tectonic effects of the Indo-Asia collision and Pamir/Tibetan plateau uplift. Short-term eustatic sea level transgressions are superimposed on this long-term regression and seem coeval with the transgression events in the other northern Peri-Tethyan sedimentary provinces for the 1st and 2nd sea incursions. However, the 3rd sea incursion is interpreted as related to tectonism. The transgressive and regressive intervals of the proto-Paratethys Sea correlate well with the reported humid and arid phases, respectively in the Qaidam and Xining basins, thus demonstrating the role of the proto-Paratethys Sea as an important moisture source for the Asian interior and its regression as a contributor to Asian aridification.}, language = {en} } @misc{KellermannSchoenbergerThieken2016, author = {Kellermann, Patric and Sch{\"o}nberger, Christine and Thieken, Annegret}, title = {Large-scale application of the flood damage model RAilway Infrastructure Loss (RAIL)}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {555}, issn = {1866-8372}, doi = {10.25932/publishup-41191}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411915}, pages = {15}, year = {2016}, abstract = {Experience has shown that river floods can significantly hamper the reliability of railway networks and cause extensive structural damage and disruption. As a result, the national railway operator in Austria had to cope with financial losses of more than EUR 100 million due to flooding in recent years. Comprehensive information on potential flood risk hot spots as well as on expected flood damage in Austria is therefore needed for strategic flood risk management. In view of this, the flood damage model RAIL (RAilway Infrastructure Loss) was applied to estimate (1) the expected structural flood damage and (2) the resulting repair costs of railway infrastructure due to a 30-, 100- and 300-year flood in the Austrian Mur River catchment. The results were then used to calculate the expected annual damage of the railway subnetwork and subsequently analysed in terms of their sensitivity to key model assumptions. Additionally, the impact of risk aversion on the estimates was investigated, and the overall results were briefly discussed against the background of climate change and possibly resulting changes in flood risk. The findings indicate that the RAIL model is capable of supporting decision-making in risk management by providing comprehensive risk information on the catchment level. It is furthermore demonstrated that an increased risk aversion of the railway operator has a marked influence on flood damage estimates for the study area and, hence, should be considered with regard to the development of risk management strategies.}, language = {en} } @article{Kleinwaechter2012, author = {Kleinw{\"a}chter, Kai}, title = {Einleitung}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81267}, pages = {9 -- 10}, year = {2012}, language = {de} } @article{KraemerKleinwaechter2012, author = {Kr{\"a}mer, Raimund and Kleinw{\"a}chter, Kai}, title = {Brandenburg ist klimapolitisch gut aufgestellt!}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81285}, pages = {11 -- 20}, year = {2012}, language = {de} } @article{LauterbachWittPlessenetal.2014, author = {Lauterbach, Stefan and Witt, Roman and Plessen, Birgit and Dulski, Peter and Prasad, Sushma and Mingram, Jens and Gleixner, Gerd and Hettler-Riedel, Sabine and Stebich, Martina and Schnetger, Bernhard and Schwalb, Antje and Schwarz, Anja}, title = {Climatic imprint of the mid-latitude Westerlies in the Central Tian Shan of Kyrgyzstan and teleconnections to North Atlantic climate variability during the last 6000 years}, series = {The Holocene : an interdisciplinary journal focusing on recent environmental change}, volume = {24}, journal = {The Holocene : an interdisciplinary journal focusing on recent environmental change}, number = {8}, publisher = {Sage Publ.}, address = {London}, issn = {0959-6836}, doi = {10.1177/0959683614534741}, pages = {970 -- 984}, year = {2014}, abstract = {In general, a moderate drying trend is observed in mid-latitude arid Central Asia since the Mid-Holocene, attributed to the progressively weakening influence of the mid-latitude Westerlies on regional climate. However, as the spatio-temporal pattern of this development and the underlying climatic mechanisms are yet not fully understood, new high-resolution paleoclimate records from this region are needed. Within this study, a sediment core from Lake Son Kol (Central Kyrgyzstan) was investigated using sedimentological, (bio) geochemical, isotopic, and palynological analyses, aiming at reconstructing regional climate development during the last 6000 years. Biogeochemical data, mainly reflecting summer moisture conditions, indicate predominantly wet conditions until 4950 cal. yr BP, succeeded by a pronounced dry interval between 4950 and 3900 cal. yr BP. In the following, a return to wet conditions and a subsequent moderate drying trend until present times are observed. This is consistent with other regional paleoclimate records and likely reflects the gradual Late Holocene diminishment of the amount of summer moisture provided by the mid-latitude Westerlies. However, climate impact of the Westerlies was apparently not only restricted to the summer season but also significant during winter as indicated by recurrent episodes of enhanced allochthonous input through snowmelt, occurring before 6000 cal. yr BP and at 5100-4350, 3450-2850, and 1900-1500 cal. yr BP. The distinct similar to 1500year periodicity of these episodes of increased winter precipitation in Central Kyrgyzstan resembles similar cyclicities observed in paleoclimate records around the North Atlantic, likely indicating a hemispheric-scale climatic teleconnection and an impact of North Atlantic Oscillation (NAO) variability in Central Asia.}, language = {en} } @misc{LauterbachWittPlessenetal.2017, author = {Lauterbach, Stefan and Witt, Roman and Plessen, Birgit and Dulski, Peter and Prasad, Sushma and Mingram, Jens and Gleixner, Gerd and Hettler-Riedel, Sabine and Stebich, Martina and Schnetger, Bernhard and Schwalb, Antje and Schwarz, Anja}, title = {Climatic imprint of the mid-latitude Westerlies in the Central Tian Shan of Kyrgyzstan and teleconnections to North Atlantic climate variability during the last 6000 years}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-404085}, pages = {15}, year = {2017}, abstract = {In general, a moderate drying trend is observed in mid-latitude arid Central Asia since the Mid-Holocene, attributed to the progressively weakening influence of the mid-latitude Westerlies on regional climate. However, as the spatio-temporal pattern of this development and the underlying climatic mechanisms are yet not fully understood, new high-resolution paleoclimate records from this region are needed. Within this study, a sediment core from Lake Son Kol (Central Kyrgyzstan) was investigated using sedimentological, (bio) geochemical, isotopic, and palynological analyses, aiming at reconstructing regional climate development during the last 6000 years. Biogeochemical data, mainly reflecting summer moisture conditions, indicate predominantly wet conditions until 4950 cal. yr BP, succeeded by a pronounced dry interval between 4950 and 3900 cal. yr BP. In the following, a return to wet conditions and a subsequent moderate drying trend until present times are observed. This is consistent with other regional paleoclimate records and likely reflects the gradual Late Holocene diminishment of the amount of summer moisture provided by the mid-latitude Westerlies. However, climate impact of the Westerlies was apparently not only restricted to the summer season but also significant during winter as indicated by recurrent episodes of enhanced allochthonous input through snowmelt, occurring before 6000 cal. yr BP and at 5100-4350, 3450-2850, and 1900-1500 cal. yr BP. The distinct similar to 1500year periodicity of these episodes of increased winter precipitation in Central Kyrgyzstan resembles similar cyclicities observed in paleoclimate records around the North Atlantic, likely indicating a hemispheric-scale climatic teleconnection and an impact of North Atlantic Oscillation (NAO) variability in Central Asia.}, language = {en} } @article{Lederer2012, author = {Lederer, Markus}, title = {Klimapolitik zwischen Kyoto und Canc{\´u}n}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81364}, pages = {83 -- 92}, year = {2012}, abstract = {In diesem einleitenden Beitrag des Themenschwerpunktes wird der Hintergrund der internationalen Klimaverhandlungen erl{\"a}utert und die Ergebnisse des Kopenhagen-Akkords vorgestellt. Angesichts des Scheiterns der Kopenhagener Konferenz muss die zeitnahe Schließung eines rechtlich bindenden, globalen Klimaabkommens als unwahrscheinlich gelten. Die Klimapolitik wird zuk{\"u}nftig verst{\"a}rkt auf nationalstaatlicher und transnationaler Ebene erfolgen.}, language = {de} } @misc{LenkRybskiHeidrichetal.2017, author = {Lenk, Stephan and Rybski, Diego and Heidrich, Oliver and Dawson, Richard J. and Kropp, J{\"u}rgen}, title = {Costs of sea dikes}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {638}, issn = {1866-8372}, doi = {10.25932/publishup-41840}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418401}, pages = {765 -- 779}, year = {2017}, abstract = {Failure to consider the costs of adaptation strategies can be seen by decision makers as a barrier to implementing coastal protection measures. In order to validate adaptation strategies to sea-level rise in the form of coastal protection, a consistent and repeatable assessment of the costs is necessary. This paper significantly extends current knowledge on cost estimates by developing - and implementing using real coastal dike data - probabilistic functions of dike costs. Data from Canada and the Netherlands are analysed and related to published studies from the US, UK, and Vietnam in order to provide a reproducible estimate of typical sea dike costs and their uncertainty. We plot the costs divided by dike length as a function of height and test four different regression models. Our analysis shows that a linear function without intercept is sufficient to model the costs, i.e. fixed costs and higher-order contributions such as that due to the volume of core fill material are less significant. We also characterise the spread around the regression models which represents an uncertainty stemming from factors beyond dike length and height. Drawing an analogy with project cost overruns, we employ log-normal distributions and calculate that the range between 3x and x/3 contains 95\% of the data, where x represents the corresponding regression value. We compare our estimates with previously published unit costs for other countries. We note that the unit costs depend not only on the country and land use (urban/non-urban) of the sites where the dikes are being constructed but also on characteristics included in the costs, e.g. property acquisition, utility relocation, and project management. This paper gives decision makers an order of magnitude on the protection costs, which can help to remove potential barriers to develop-ing adaptation strategies. Although the focus of this research is sea dikes, our approach is applicable and transferable to other adaptation measures.}, language = {en} } @misc{LichtDupontNivetPullenetal.2016, author = {Licht, Alexis and Dupont-Nivet, Guillaume and Pullen, Alex and Kapp, Paul and Abels, Hemmo A. and Lai, Zulong and Guo, ZhaoJie and Abell, Jordan and Giesler, Dominique}, title = {Resilience of the Asian atmospheric circulation shown by paleogene dust provenance}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1114}, issn = {1866-8372}, doi = {10.25932/publishup-43638}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436381}, pages = {8}, year = {2016}, abstract = {The onset of modern central Asian atmospheric circulation is traditionally linked to the interplay of surface uplift of the Mongolian and Tibetan-Himalayan orogens, retreat of the Paratethys sea from central Asia and Cenozoic global cooling. Although the role of these players has not yet been unravelled, the vast dust deposits of central China support the presence of arid conditions and modern atmospheric pathways for the last 25 million years (Myr). Here, we present provenance data from older (42-33 Myr) dust deposits, at a time when the Tibetan Plateau was less developed, the Paratethys sea still present in central Asia and atmospheric pCO(2) much higher. Our results show that dust sources and near-surface atmospheric circulation have changed little since at least 42 Myr. Our findings indicate that the locus of central Asian high pressures and concurrent aridity is a resilient feature only modulated by mountain building, global cooling and sea retreat.}, language = {en} } @techreport{LudolphŠedova2021, type = {Working Paper}, author = {Ludolph, Lars and Šedov{\´a}, Barbora}, title = {Global food prices, local weather and migration in Sub-Saharan Africa}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {26}, issn = {2628-653X}, doi = {10.25932/publishup-49494}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-494946}, pages = {53}, year = {2021}, abstract = {In this paper, we study the effect of exogenous global crop price changes on migration from agricultural and non-agricultural households in Sub-Saharan Africa. We show that, similar to the effect of positive local weather shocks, the effect of a locally-relevant global crop price increase on household out-migration depends on the initial household wealth. Higher international producer prices relax the budget constraint of poor agricultural households and facilitate migration. The order of magnitude of a standardized price effect is approx. one third of the standardized effect of a local weather shock. Unlike positive weather shocks, which mostly facilitate internal rural-urban migration, positive income shocks through rising producer prices only increase migration to neighboring African countries, likely due to the simultaneous decrease in real income in nearby urban areas. Finally, we show that while higher producer prices induce conflict, conflict does not play a role for the household decision to send a member as a labor migrant.}, language = {en} } @phdthesis{Macaulay2013, author = {Macaulay, Euan Angus}, title = {The orogenic evolution of the Central Kyrgyz Tien Shan}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-68985}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Intra-continental mountain belts typically form as a result of tectonic forces associated with distant plate collisions. In general, each mountain belt has a distinctive morphology and orogenic evolution that is highly dependent on the unique distribution and geometries of inherited structures and other crustal weaknesses. In this thesis, I have investigated the complex and irregular Cenozoic orogenic evolution of the Central Kyrgyz Tien Shan in Central Asia, which is presently one of the most active intra-continental mountain belts in the world. This work involved combining a broad array of datasets, including thermochronologic, magnetostratigraphic, sediment provenance and stable isotope data, to identify and date various changes in tectonic deformation, climate and surface processes. Many of these changes are linked and can ultimately be related to regional-scale processes that altered the orogenic evolution of the Central Kyrgyz Tien Shan. The Central Kyrgyz Tien Shan contains a sub-parallel series of structures that were reactivated in the late Cenozoic in response to the tectonic forces associated with the distant India-Eurasia collision. Over time, slip on the various reactivated structures created the succession of mountain ranges and intermontane basins which characterises the modern morphology of the region. In this thesis, new quantitative constraints on the exhumation histories of several mountain ranges have been obtained by using low temperature thermochronological data from 95 samples (zircon (U-Th)/He, apatite fission track and (U-Th)/He). Time-temperature histories derived by modelling the thermochronologic data of individual samples identify at least two stages of Cenozoic cooling in most of the region's mountain ranges: (1) initially low cooling rates (<1°C/Myr) during the tectonic quiescent period and (2) increased cooling in the late Cenozoic, which occurred diachronously and with variable magnitude in different ranges. This second cooling stage is interpreted to represent increased erosion caused by active deformation, and in many of the sampled mountain ranges, provides the first available constraints on the timing of late Cenozoic deformation. New constraints on the timing of deformation have also been derived from the sedimentary record of intermontane basins. In the intermontane Issyk Kul basin, new magnetostratigraphic data from two sedimentary sections suggests that deposition of the first Cenozoic syn-tectonic sediments commenced at ~26 Ma. Zircon U-Pb provenance data, paleocurrent and conglomerate clast analysis reveals that these sediments were sourced from the Terskey Range to the south of the basin, suggesting that the onset of the late Cenozoic deformation occurred >26 Ma in that particular range. Elsewhere, growth strata relationships are used to identify syn-tecotnic deposition and constrain the timing of nearby deformation. Collectively, these new constraints obtained from thermochronologic and sedimentary data have allowed me to infer the spatiotemporal distribution of deformation in a transect through the Central Kyrgyz Tien Shan, and determine the order in which mountain ranges started deforming. These data suggest that deformation began in a few widely-spaced mountain ranges in the late Oligocene and early Miocene. Typically, these earlier mountain ranges are bounded on at least one side by a reactivated structure, which probably corresponds to the frictionally weakest and most suitably orientated inherited structures for accommodating the roughly north-south directed horizontal crustal shortening of the late Cenozoic. Moreover, tectonically-induced rock uplift in the Terskey Range, following the reactivation of the bounding structure before 26 Ma, likely caused significant surface uplift across the range, which in turn lead to enhanced orographic precipitation. These wetter conditions have been inferred from stable isotope data collected in the two magnetostratigraphically-dated sections in the Issyk Kul basin. Subsequently, in the late Miocene (~12‒5 Ma), more mountain ranges and inherited structures appear to have started actively deforming. Importantly, the onset of deformation at these locations in the late Miocene coincides with an increase in exhumation of ranges that had started deforming earlier in the late Oligocene‒early Miocene. Based on this observation, I have suggested that there must have been an overall increase in the rate of horizontal crustal shortening across the Central Kyrgyz Tien Shan, which likely relates to regional tectonic changes that affected much of Central Asia. Many of the mountain ranges that started deforming in the late Miocene were associated with out-of-sequence tectonic reactivation and initiation, which lead to the partitioning of larger intermontane basins. Moreover, within most of the intermontane basins in the Central Kyrgyz Tien Shan, this inferred late Miocene increase in horizontal crustal shortening occurs roughly at the same time as an increase in sedimentation rates and a significant change sediment composition. Therefore, I have suggested that the overall magnitude of deformational processes increased in the late Miocene, promoting more flexural subsidence in the intermontane basins of the Central Kyrgyz Tien Shan.}, language = {en} } @article{MargirierBraunGautheronetal.2019, author = {Margirier, Audrey and Braun, Jean and Gautheron, Cecile and Carcaillet, Julien and Schwartz, Stephane and Jamme, Rosella Pinna and Stanley, Jessica}, title = {Climate control on Early Cenozoic denudation of the Namibian margin as deduced from new thermochronological constraints}, series = {Earth \& planetary science letters}, volume = {527}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2019.115779}, pages = {11}, year = {2019}, abstract = {The processes that control long term landscape evolution in continental interiors and, in particular, along passive margins such as in southern Africa, are still the subject of much debate (e.g. Braun, 2018). Although today the Namibian margin is characterized by an arid climate, it has experienced climatic fluctuations during the Cenozoic and, yet, to date no study has documented the potential role of climate on its erosion history. In western Namibia, the Brandberg Massif, an erosional remnant or inselberg, provides a good opportunity to document the Cenozoic denudation history of the margin using the relationship between rock cooling or exhumation ages and their elevation. Here we provide new apatite (UThSm)/He dates on the Brandberg Inselberg that range from 151 +/- 12 to 30 +/- 2 Ma. Combined with existing apatite fission track data, they yield new constraints on the denudation history of the margin. These data document two main cooling phases since continental break-up 130 Myr ago, a rapid one (similar to 10 degrees C/Myr) following break-up and a slower one (similar to 12 degrees C/Myr) between 65 and 35 Ma. We interpret them respectively to be related to escarpment erosion following rifting and continental break-up and as a phase of enhanced denudation during the Early Eocene Climatic Optimum. We propose that during the Early Eocene Climatic Optimum chemical weathering was important and contributed significantly to the denudation of the Namibian margin and the formation of a pediplain around the Brandberg and enhanced valley incision within the massif. Additionally, aridification of the region since 35 Ma has resulted in negligible denudation rates since that time. (C) 2019 Elsevier B.V. All rights reserved.}, language = {en} } @misc{MolnosMamdouhPetrietal.2017, author = {Molnos, Sonja and Mamdouh, Tarek and Petri, Stefan and Nocke, Thomas and Weinkauf, Tino and Coumou, Dim}, title = {A network-based detection scheme for the jet stream core}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {625}, issn = {1866-8372}, doi = {10.25932/publishup-41909}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-419099}, pages = {75 -- 89}, year = {2017}, abstract = {The polar and subtropical jet streams are strong upper-level winds with a crucial influence on weather throughout the Northern Hemisphere midlatitudes. In particular, the polar jet is located between cold arctic air to the north and warmer subtropical air to the south. Strongly meandering states therefore often lead to extreme surface weather. Some algorithms exist which can detect the 2-D (latitude and longitude) jets' core around the hemisphere, but all of them use a minimal threshold to determine the subtropical and polar jet stream. This is particularly problematic for the polar jet stream, whose wind velocities can change rapidly from very weak to very high values and vice versa. We develop a network-based scheme using Dijkstra's shortest-path algorithm to detect the polar and subtropical jet stream core. This algorithm not only considers the commonly used wind strength for core detection but also takes wind direction and climatological latitudinal position into account. Furthermore, it distinguishes between polar and subtropical jet, and between separate and merged jet states. The parameter values of the detection scheme are optimized using simulated annealing and a skill function that accounts for the zonal-mean jet stream position (Rikus, 2015). After the successful optimization process, we apply our scheme to reanalysis data covering 1979-2015 and calculate seasonal-mean probabilistic maps and trends in wind strength and position of jet streams. We present longitudinally defined probability distributions of the positions for both jets for all on the Northern Hemisphere seasons. This shows that winter is characterized by two well-separated jets over Europe and Asia (ca. 20 degrees W to 140 degrees E). In contrast, summer normally has a single merged jet over the western hemisphere but can have both merged and separated jet states in the eastern hemisphere. With this algorithm it is possible to investigate the position of the jets' cores around the hemisphere and it is therefore very suitable to analyze jet stream patterns in observations and models, enabling more advanced model-validation.}, language = {en} } @article{Mueller2012, author = {M{\"u}ller, Melanie}, title = {Die Zivilgesellschaft in der internationalen Klimapolitik}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81331}, pages = {59 -- 66}, year = {2012}, abstract = {Die Zivilgesellschaft hat dazu beigetragen, dass die Klimakonferenz in Kopenhagen zu einem Medienereignis wurde. Fernab großer Demonstrationen haben Nichtregierungsorganisationen (NRO) seit Jahren einen guten Zugang zu den internationalen Klimaverhandlungen. Am Beispiel von Chile wird gezeigt, wie Nichtregierungsorganisationen durch professionellen Lobbyismus ihre Positionen in politische Prozesse einspeisen. Sie befinden sich in einem Spannungsfeld von Kooperation und Instrumentalisierung durch politische Entscheidungstr{\"a}ger.}, language = {de} } @misc{MuenchKipfstuhlFreitagetal.2017, author = {M{\"u}nch, Thomas and Kipfstuhl, Sepp and Freitag, Johannes and Meyer, Hanno and Laepple, Thomas}, title = {Constraints on post-depositional isotope modifications in East Antarctic firn from analysing temporal changes of isotope profiles}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {662}, issn = {1866-8372}, doi = {10.25932/publishup-41876}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418763}, pages = {14}, year = {2017}, abstract = {The isotopic composition of water in ice sheets is extensively used to infer past climate changes. In low-accumulation regions their interpretation is, however, challenged by poorly constrained effects that may influence the initial isotope signal during and after deposition of the snow. This is reflected in snow-pit isotope data from Kohnen Station, Antarctica, which exhibit a seasonal cycle but also strong interannual variations that contradict local temperature observations. These inconsistencies persist even after averaging many profiles and are thus not explained by local stratigraphic noise. Previous studies have suggested that post-depositional processes may significantly influence the isotopic composition of East Antarctic firn. Here, we investigate the importance of post-depositional processes within the open-porous firn (greater than or similar to 10 cm depth) at Kohnen Station by separating spatial from temporal variability. To this end, we analyse 22 isotope profiles obtained from two snow trenches and examine the temporal isotope modifications by comparing the new data with published trench data extracted 2 years earlier. The initial isotope profiles undergo changes over time due to downward advection, firn diffusion and densification in magnitudes consistent with independent estimates. Beyond that, we find further modifications of the original isotope record to be unlikely or small in magnitude (<< 1 parts per thousand RMSD). These results show that the discrepancy between local temperatures and isotopes most likely originates from spatially coherent processes prior to or during deposition, such as precipitation intermittency or systematic isotope modifications acting on drifting or loose surface snow.}, language = {en} } @misc{PaulyHelleMiramontetal.2018, author = {Pauly, Maren and Helle, Gerhard and Miramont, C{\´e}cile and B{\"u}ntgen, Ulf and Treydte, Kerstin and Reinig, Frederick and Guibal, Fr{\´e}d{\´e}ric and Sivan, Olivier and Heinrich, Ingo and Riedel, Frank and Kromer, Bernd and Balanzategui, Daniel and Wacker, Lukas and Sookdeo, Adam Sookdeo and Brauer, Achim}, title = {Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1135}, issn = {1866-8372}, doi = {10.25932/publishup-45916}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459169}, pages = {10}, year = {2018}, abstract = {Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (delta O-18, delta C-13) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (delta O-18(sw)) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (delta O-18(sw)), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low delta O-18(sw)) versus Mediterranean (high delta O-18(sw)) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front.}, language = {en} } @misc{PrahlRybskiBurghoffetal.2015, author = {Prahl, Boris F. and Rybski, Diego and Burghoff, Olaf and Kropp, J{\"u}rgen}, title = {Comparison of storm damage functions and their performance}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {492}, issn = {1866-8372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-408119}, pages = {20}, year = {2015}, abstract = {Winter storms are the most costly natural hazard for European residential property. We compare four distinct storm damage functions with respect to their forecast accuracy and variability, with particular regard to the most severe winter storms. The analysis focuses on daily loss estimates under differing spatial aggregation, ranging from district to country level. We discuss the broad and heavily skewed distribution of insured losses posing difficulties for both the calibration and the evaluation of damage functions. From theoretical considerations, we provide a synthesis between the frequently discussed cubic wind-damage relationship and recent studies that report much steeper damage functions for European winter storms. The performance of the storm loss models is evaluated for two sources of wind gust data, direct observations by the German Weather Service and ERA-Interim reanalysis data. While the choice of gust data has little impact on the evaluation of German storm loss, spatially resolved coefficients of variation reveal dependence between model and data choice. The comparison shows that the probabilistic models by Heneka et al. (2006) and Prahl et al. (2012) both provide accurate loss predictions for moderate to extreme losses, with generally small coefficients of variation. We favour the latter model in terms of model applicability. Application of the versatile deterministic model by Klawa and Ulbrich (2003) should be restricted to extreme loss, for which it shows the least bias and errors comparable to the probabilistic model by Prahl et al. (2012).}, language = {en} } @article{RohrmannHeermanceKappetal.2013, author = {Rohrmann, Alexander and Heermance, Richard and Kapp, Paul and Cai, Fulong}, title = {Wind as the primary driver of erosion in the Qaidam Basin, China}, series = {Earth \& planetary science letters}, volume = {374}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2013.03.011}, pages = {1 -- 10}, year = {2013}, abstract = {Deserts are a major source of loess and may undergo substantial wind-erosion as evidenced by yardang fields, deflation pans, and wind-scoured bedrock landscapes. However, there are few quantitative estimates of bedrock removal by wind abrasion and deflation. Here, we report wind-erosion rates in the western Qaidam Basin in central China based on measurements of cosmogenic Be-10 in exhumed Miocene sedimentary bedrock. Sedimentary bedrock erosion rates range from 0.05 to 0.4 mm/yr, although the majority of measurements cluster at 0.125 +/- 0.05 mm/yr. These results, combined with previous work, indicate that strong winds, hyper-aridity, exposure of friable Neogene strata, and ongoing rock deformation and uplift in the western Qaidam Basin have created an environment where wind, instead of water, is the dominant agent of erosion and sediment transport. Its geographic location (upwind) combined with volumetric estimates suggest that the Qaidam Basin is a major source (up to 50\%) of dust to the Chinese Loess Plateau to the east. The cosmogenically derived wind erosion rates are within the range of erosion rates determined from glacial and fluvial dominated landscapes worldwide, exemplifying the effectiveness of wind to erode and transport significant quantities of bedrock.}, language = {en} } @article{Roettgen2012, author = {R{\"o}ttgen, Norbert}, title = {Regierungserkl{\"a}rung zu den Ergebnissen der Klimakonferenz in Durban}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81376}, pages = {93 -- 100}, year = {2012}, language = {de} } @misc{ScheweLevermann2017, author = {Schewe, Jacob and Levermann, Anders}, title = {Non-linear intensification of Sahel rainfall as a possible dynamic response to future warming}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {630}, doi = {10.25932/publishup-41911}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-419114}, pages = {495 -- 505}, year = {2017}, abstract = {Projections of the response of Sahel rainfall to future global warming diverge significantly. Meanwhile, paleoclimatic records suggest that Sahel rainfall is capable of abrupt transitions in response to gradual forcing. Here we present climate modeling evidence for the possibility of an abrupt intensification of Sahel rainfall under future climate change. Analyzing 30 coupled global climate model simulations, we identify seven models where central Sahel rainfall increases by 40 to 300\% over the 21st century, owing to a northward expansion of the West African monsoon domain. Rainfall in these models is non-linearly related to sea surface temperature (SST) in the tropical Atlantic and Mediterranean moisture source regions, intensifying abruptly beyond a certain SST warming level. We argue that this behavior is consistent with a self-amplifying dynamic-thermodynamical feedback, implying that the gradual increase in oceanic moisture availability under warming could trigger a sudden intensification of monsoon rainfall far inland of today's core monsoon region.}, language = {en} } @article{Schroeder2012, author = {Schr{\"o}der, Miriam}, title = {China und Indien}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81311}, pages = {41 -- 49}, year = {2012}, abstract = {Der Artikel analysiert die neue Rolle aufsteigender Schwellenl{\"a}nder in den internationalen Klimaverhandlungen am Beispiel Chinas und Indiens. Die Ablehnung verbindlicher Reduktionsziele f{\"u}r Treibhausgase wurde in Kopenhagen als Blockadepolitik beider L{\"a}nder gewertet. China und Indien k{\"o}nnen sich in ihrer Position behaupten, da ihr gestiegenes Gewicht in der multipolaren Weltordnung und die Unt{\"a}tigkeit f{\"u}hrender Industriel{\"a}nder ihre Verhandlungsposition st{\"a}rkt. Die Autorin diskutiert Kooperationsm{\"o}glichkeiten auf subnationaler Ebene, die die Blockadeposition nationaler Regierungen umgehen k{\"o}nnen.}, language = {de} } @article{Schunz2012, author = {Schunz, Simon}, title = {Gescheiterte Klimapolitik?}, series = {Klimapolitik International}, journal = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-6222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-81347}, pages = {67 -- 72}, year = {2012}, abstract = {Der Kopenhagener Klimagipfel 2009 ist mit Spannung erwartet worden. Erreicht wurde lediglich ein Minimalkonsens. Der Autor liefert eine akteurszentrierte Deutung des Kopenhagener Abkommens und stellt die Frage nach dem Pr{\"a}zedenzcharakter der Verhandlungen: Handelte es sich um ein einmaliges Versagen multilateraler Diplomatie oder um einen Vorgeschmack auf die weltpolitische Routine des 21. Jahrhunderts?}, language = {de} } @misc{SeibertMerzApel2017, author = {Seibert, Mathias and Merz, Bruno and Apel, Heiko}, title = {Seasonal forecasting of hydrological drought in the Limpopo Basin}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {626}, doi = {10.25932/publishup-41844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-418442}, pages = {1611 -- 1629}, year = {2017}, abstract = {The Limpopo Basin in southern Africa is prone to droughts which affect the livelihood of millions of people in South Africa, Botswana, Zimbabwe and Mozambique. Seasonal drought early warning is thus vital for the whole region. In this study, the predictability of hydrological droughts during the main runoff period from December to May is assessed using statistical approaches. Three methods (multiple linear models, artificial neural networks, random forest regression trees) are compared in terms of their ability to forecast streamflow with up to 12 months of lead time. The following four main findings result from the study. 1. There are stations in the basin at which standardised streamflow is predictable with lead times up to 12 months. The results show high inter-station differences of forecast skill but reach a coefficient of determination as high as 0.73 (cross validated). 2. A large range of potential predictors is considered in this study, comprising well-established climate indices, customised teleconnection indices derived from sea surface temperatures and antecedent streamflow as a proxy of catchment conditions. El Nino and customised indices, representing sea surface temperature in the Atlantic and Indian oceans, prove to be important teleconnection predictors for the region. Antecedent streamflow is a strong predictor in small catchments (with median 42\% explained variance), whereas teleconnections exert a stronger influence in large catchments. 3. Multiple linear models show the best forecast skill in this study and the greatest robustness compared to artificial neural networks and random forest regression trees, despite their capabilities to represent nonlinear relationships. 4. Employed in early warning, the models can be used to forecast a specific drought level. Even if the coefficient of determination is low, the forecast models have a skill better than a climatological forecast, which is shown by analysis of receiver operating characteristics (ROCs). Seasonal statistical forecasts in the Limpopo show promising results, and thus it is recommended to employ them as complementary to existing forecasts in order to strengthen preparedness for droughts.}, language = {en} } @article{Streck2021, author = {Streck, Charlotte}, title = {Strengthening the Paris Agreement by holding non-state actors accountable}, series = {Transnational environmental law}, volume = {10}, journal = {Transnational environmental law}, number = {3}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, issn = {2047-1025}, doi = {10.1017/S2047102521000091}, pages = {493 -- 515}, year = {2021}, abstract = {While the intergovernmental climate regime increasingly recognizes the role of non-state actors in achieving the goals of the Paris Agreement (PA), the normative linkages between the intergovernmental climate regime and the non-state dominated 'transnational partnership governance' remain vague and tentative. A formalized engagement of the intergovernmental climate regime with transnational partnerships can increase the effectiveness of partnerships in delivering on climate mitigation and adaptation, thereby complementing rather than replacing government action. The proposed active engagement with partnerships would include (i) collecting and analyzing information to develop and prioritize areas for transnational and partnership engagement; (ii) defining minimum criteria and procedural requirements to be listed on an enhanced Non-state Actor Zone for Climate Action platform; (iii) actively supporting strategic initiatives; (iv) facilitating market or non-market finance as part of Article 6 PA; and (v) evaluating the effectiveness of partnerships in the context of the enhanced transparency framework (Article 13 PA) and the global stocktake (Article 14 PA). The UNFCCC Secretariat could facilitate engagement and problem solving by actively orchestrating transnational partnerships. Constructing effective implementation partnerships, recording their mitigation and adaptation goals, and holding them accountable may help to move climate talks from rhetoric to action.}, language = {en} } @phdthesis{Thiede2005, author = {Thiede, Rasmus Christoph}, title = {Tectonic and climatic controls on orogenic processes : the Northwest Himalaya, India}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-2281}, school = {Universit{\"a}t Potsdam}, year = {2005}, abstract = {The role of feedback between erosional unloading and tectonics controlling the development of the Himalaya is a matter of current debate. The distribution of precipitation is thought to control surface erosion, which in turn results in tectonic exhumation as an isostatic compensation process. Alternatively, subsurface structures can have significant influence in the evolution of this actively growing orogen. Along the southern Himalayan front new 40Ar/39Ar white mica and apatite fission track (AFT) thermochronologic data provide the opportunity to determine the history of rock-uplift and exhumation paths along an approximately 120-km-wide NE-SW transect spanning the greater Sutlej region of the northwest Himalaya, India. 40Ar/39Ar data indicate, consistent with earlier studies that first the High Himalayan Crystalline, and subsequently the Lesser Himalayan Crystalline nappes were exhumed rapidly during Miocene time, while the deformation front propagated to the south. In contrast, new AFT data delineate synchronous exhumation of an elliptically shaped, NE-SW-oriented ~80 x 40 km region spanning both crystalline nappes during Pliocene-Quaternary time. The AFT ages correlate with elevation, but show within the resolution of the method no spatial relationship to preexisting major tectonic structures, such as the Main Central Thrust or the Southern Tibetan Fault System. Assuming constant exhumation rates and geothermal gradient, the rocks of two age vs. elevation transects were exhumed at ~1.4 \&\#177;0.2 and ~1.1 \&\#177;0.4 mm/a with an average cooling rate of ~50-60 \&\#176;C/Ma during Pliocene-Quaternary time. The locus of pronounced exhumation defined by the AFT data coincides with a region of enhanced precipitation, high discharge, and sediment flux rates under present conditions. We therefore hypothesize that the distribution of AFT cooling ages might reflect the efficiency of surface processes and fluvial erosion, and thus demonstrate the influence of erosion in localizing rock-uplift and exhumation along southern Himalayan front, rather than encompassing the entire orogen.Despite a possible feedback between erosion and exhumation along the southern Himalayan front, we observe tectonically driven, crustal exhumation within the arid region behind the orographic barrier of the High Himalaya, which might be related to and driven by internal plateau forces. Several metamorphic-igneous gneiss dome complexes have been exhumed between the High Himalaya to the south and Indus-Tsangpo suture zone to the north since the onset of Indian-Eurasian collision ~50 Ma ago. Although the overall tectonic setting is characterized by convergence the exhumation of these domes is accommodated by extensional fault systems.Along the Indian-Tibetan border the poorly described Leo Pargil metamorphic-igneous gneiss dome (31-34\&\#176;N/77-78\&\#176;E) is located within the Tethyan Himalaya. New field mapping, structural, and geochronologic data document that the western flank of the Leo Pargil dome was formed by extension along temporally linked normal fault systems. Motion on a major detachment system, referred to as the Leo Pargil detachment zone (LPDZ) has led to the juxtaposition of low-grade metamorphic, sedimentary rocks in the hanging wall and high-grade metamorphic gneisses in the footwall. However, the distribution of new 40Ar/39Ar white mica data indicate a regional cooling event during middle Miocene time. New apatite fission track (AFT) data demonstrate that subsequently more of the footwall was extruded along the LPDZ in a brittle stage between 10 and 2 Ma with a minimum displacement of ~9 km. Additionally, AFT-data indicate a regional accelerated cooling and exhumation episode starting at ~4 Ma. Thus, tectonic processes can affect the entire orogenic system, while potential feedbacks between erosion and tectonics appear to be limited to the windward sides of an orogenic systems.}, language = {en} } @phdthesis{Totz2018, author = {Totz, Sonja Juliana}, title = {Modeling and data analysis of large-scale atmosphere dynamics associated with extreme weather}, school = {Universit{\"a}t Potsdam}, pages = {xii, 166}, year = {2018}, abstract = {In the last decades the frequency and intensity of extreme weather events like heat waves and heavy rainfall have increased and are at least partly linked to global warming. These events can have a strong impact on agricultural and economic production and, thereby, on society. Thus, it is important to improve our understanding of the physical processes leading to those extreme events in order to provide accurate near-term and long-term forecasts. Thermodynamic drivers associated with global warming are well understood, but dynamical aspects of the atmosphere much less so. The dynamical aspects, while less important than the thermodynamic drivers in regards to large-scale and long-time averaged effects, play a critical role in the formation of extremes. The overall aim of this thesis is to improve our understanding of patterns, variability and trends in the global atmospheric circulation under a changing climate. In particular, in this dissertation I developed two new data-driven methods to quantitatively describe the dynamics of jet streams, Hadley cells and storm tracks. In addition, I introduce and validate a new statistical-dynamical atmosphere model that can be used to efficiently model the large-scale circulation. First, I developed a scheme based on the Dijkstra 'shortest-path' algorithm to identify jet stream cores. Using reanalysis data, I found a significant change in jet stream strength and position over the last decades: Specifically, a decrease in wind speeds and a spatial shift toward the poles. This work also shows that the splitting or merging of the polar front jet stream and the subtropical jet stream depends on the season and longitudinal position. In a follow-up study, I analyzed trends in the latitudinal position of the poleward edge of the Hadley cell and subtropical jet stream core for all longitudes. These trends depend strongly on longitude and thus the impacts of tropical expansion might be pronounced in some regions and absent in others. The second approach was to develop an empirical forecast method for European and Mediterranean winter precipitation. This prediction algorithm innovatively incorporates the spatial patterns of predictors in autumn using clustering analyses. I identified the most important precursors (snow cover in Eurasia, Barents and Kara sea ice concentrations as well as sea surface temperature in the Atlantic and Mediterranean region) for the precipitation prediction. This forecast algorithm had higher forecast skills than conventionally employed methods such as Canonical Correlation Analysis or operational systems using climate models. The last approach was to examine the atmospheric circulation using the novel statisticaldynamical atmosphere model Aeolus. First, I validated the model's depiction of the largescale circulation in terms of Hadley circulation, jet streams, storm tracks and planetary waves. To do so, I performed a parameter optimization using simulated annealing. Next, I investigated the sensitivity of the large-scale circulation to three different temperature components: global mean temperature, meridional temperature gradient and zonal temperature gradient. The model experiment showed that the strength of the Hadley cell, storm tracks and jet streams depend almost linearly on both the global mean temperature and the meridional temperature gradient, whereas the zonal temperature gradient is shown to have little or no influence. The magnitude of planetary waves is clearly affected by all three temperature components. Finally, the width of the Hadley cell behaves nonlinearly with respect to all three temperature components. These findings might have profound consequences for climate modeling of the Mediterranean region. The latitudinal poleward trend of the Hadley cell edge position might become stronger under climate change according to the results with Aeolus. These changes would lead to a substantial reduction of the winter precipitation in the Mediterranean region. In this case seasonal empirical forecast methods, like the clustering-based prediction scheme, will play an important role for forecasting seasonal droughts in advance such that water managers and politicians can mitigate impacts.}, language = {en} } @article{Ungelenk2020, author = {Ungelenk, Johannes}, title = {{\´E}mile Zola's Climate History of the Second Empire}, series = {Ecozon@: European Journal of Literature, Culture and Environment}, volume = {11}, journal = {Ecozon@: European Journal of Literature, Culture and Environment}, number = {1}, publisher = {Alcal{\´a} de Henares}, address = {Instituto Universitario de Investigaci{\´o}n en Estudios Norteamericanos "Benjam{\´i}n Franklin", Universidad de Alcal{\´a}}, issn = {2171-9594}, doi = {10.37536/ECOZONA.2020.11.1.3181}, pages = {9 -- 26}, year = {2020}, abstract = {This article looks at {\´E}mile Zola's novel cycle Les Rougon-Macquart and argues that it describes its subject, the Second Empire, as a warming climate tending toward climate catastrophe. Zola's affinity to the notion of climate is shown to be linked to his poetic employment of the concept of 'milieu', inspired by Hippolyte Taine. Close readings of selected passages from the Rougon-Macquart are used to work out the climatic difference between 'the old' and 'the new Paris', and the process of warming that characterises the Second Empire. Octave Mouret's department store holds a special place in the article, as it is analysed through what the article suggests calling a 'meteorotopos': a location of intensified climatic conditions that accounts for an increased interaction between human and non-human actors. The department store is also one of the many sites in the novel cycle that locally prefigure the 'global' climate catastrophe of Paris burning, in which the Second Empire perishes.}, language = {en} } @article{WeithoffGaedke2017, author = {Weithoff, Guntram and Gaedke, Ursula}, title = {Mean functional traits of lake phytoplankton reflect seasonal and inter-annual changes in nutrients, climate and herbivory}, series = {Journal of plankton research}, volume = {39}, journal = {Journal of plankton research}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0142-7873}, doi = {10.1093/plankt/fbw072}, pages = {509 -- 517}, year = {2017}, abstract = {Trait-based approaches have become increasingly successful in community ecology. They assume that the distribution of functional traits within communities responds in a predictable way to alterations in environmental forcing and that strong forcing may accelerate such trait changes. We used high frequency measurements of phytoplankton to test these assumptions. We analyzed the seasonal and long-term dynamics of the community trait mean within a multi-dimensional trait space under alternating multifactorial environmental conditions. The community trait mean exhibited a distinct recurrent annual pattern that reflected minor changes in climate, herbivory and nutrients. Independent of early spring conditions, the community trait mean was repeatedly driven into a narrow confined area in the trait space under pronounced herbivory during the clear water phase. The speed of movement was highest at the onset and the relaxation of such strong unidirectional forcing. Thus, our data support the conceptual framework of trait-based ecology that alterations in environmental conditions are systematically tracked by adjustments in the dominant functional trait values and that the speed of trait changes depends on the kind and intensity of the selection pressure. Our approach provides a sensitive tool to detect small functional differences in the community related to subtle differences in forcing.}, language = {en} } @phdthesis{Zapata2019, author = {Zapata, Sebastian Henao}, title = {Paleozoic to Pliocene evolution of the Andean retroarc between 26 and 28°S: interactions between tectonics, climate, and upper plate architecture}, doi = {10.25932/publishup-43903}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439036}, school = {Universit{\"a}t Potsdam}, pages = {139}, year = {2019}, abstract = {Interactions and feedbacks between tectonics, climate, and upper plate architecture control basin geometry, relief, and depositional systems. The Andes is part of a longlived continental margin characterized by multiple tectonic cycles which have strongly modified the Andean upper plate architecture. In the Andean retroarc, spatiotemporal variations in the structure of the upper plate and tectonic regimes have resulted in marked along-strike variations in basin geometry, stratigraphy, deformational style, and mountain belt morphology. These along-strike variations include high-elevation plateaus (Altiplano and Puna) associated with a thin-skin fold-and-thrust-belt and thick-skin deformation in broken foreland basins such as the Santa Barbara system and the Sierras Pampeanas. At the confluence of the Puna Plateau, the Santa Barbara system and the Sierras Pampeanas, major along-strike changes in upper plate architecture, mountain belt morphology, basement exhumation, and deformation style can be recognized. I have used a source to sink approach to unravel the spatiotemporal tectonic evolution of the Andean retroarc between 26 and 28°S. I obtained a large low-temperature thermochronology data set from basement units which includes apatite fission track, apatite U-Th-Sm/He, and zircon U-Th/He (ZHe) cooling ages. Stratigraphic descriptions of Miocene units were temporally constrained by U-Pb LA-ICP-MS zircon ages from interbedded pyroclastic material. Modeled ZHe ages suggest that the basement of the study area was exhumed during the Famatinian orogeny (550-450 Ma), followed by a period of relative tectonic quiescence during the Paleozoic and the Triassic. The basement experienced horst exhumation during the Cretaceous development of the Salta rift. After initial exhumation, deposition of thick Cretaceous syn-rift strata caused reheating of several basement blocks within the Santa Barbara system. During the Eocene-Oligocene, the Andean compressional setting was responsible for the exhumation of several disconnected basement blocks. These exhumed blocks were separated by areas of low relief, in which humid climate and low erosion rates facilitated the development of etchplains on the crystalline basement. The exhumed basement blocks formed an Eocene to Oligocene broken foreland basin in the back-bulge depozone of the Andean foreland. During the Early Miocene, foreland basin strata filled up the preexisting Paleogene topography. The basement blocks in lower relief positions were reheated; associated geothermal gradients were higher than 25°C/km. Miocene volcanism was responsible for lateral variations on the amount of reheating along the Campo-Arenal basin. Around 12 Ma, a new deformational phase modified the drainage network and fragmented the lacustrine system. As deformation and rock uplift continued, the easily eroded sedimentary cover was efficiently removed and reworked by an ephemeral fluvial system, preventing the development of significant relief. After ~6 Ma, the low erodibility of the basement blocks which began to be exposed caused relief increase, leading to the development of stable fluvial systems. Progressive relief development modified atmospheric circulation, creating a rainfall gradient. After 3 Ma, orographic rainfall and high relief lead to the development of proximal fluvial-gravitational depositional systems in the surrounding basins.}, language = {en} } @misc{ZimmermannRaschkeEppetal.2017, author = {Zimmermann, Heike Hildegard and Raschke, Elena and Epp, Laura Saskia and Stoof-Leichsenring, Kathleen Rosemarie and Schwamborn, Georg and Schirrmeister, Lutz and Overduin, Pier Paul and Herzschuh, Ulrike}, title = {Sedimentary ancient DNA and pollen reveal the composition of plant organic matter in Late Quaternary permafrost sediments of the Buor Khaya Peninsula (north-eastern Siberia)}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {670}, issn = {1866-8372}, doi = {10.25932/publishup-41713}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-417130}, pages = {22}, year = {2017}, abstract = {Organic matter deposited in ancient, ice-rich permafrost sediments is vulnerable to climate change and may contribute to the future release of greenhouse gases; it is thus important to get a better characterization of the plant organic matter within such sediments. From a Late Quaternary permafrost sediment core from the Buor Khaya Peninsula, we analysed plant-derived sedimentary ancient DNA (sedaDNA) to identify the taxonomic composition of plant organic matter, and undertook palynological analysis to assess the environmental conditions during deposition. Using sedaDNA, we identified 154 taxa and from pollen and non-pollen palynomorphs we identified 83 taxa. In the deposits dated between 54 and 51 kyr BP, sedaDNA records a diverse low-centred polygon plant community including recurring aquatic pond vegetation while from the pollen record we infer terrestrial open-land vegetation with relatively dry environmental conditions at a regional scale. A fluctuating dominance of either terrestrial or swamp and aquatic taxa in both proxies allowed the local hydrological development of the polygon to be traced. In deposits dated between 11.4 and 9.7 kyr BP (13.4-11.1 cal kyr BP), sedaDNA shows a taxonomic turnover to moist shrub tundra and a lower taxonomic richness compared to the older samples. Pollen also records a shrub tundra community, mostly seen as changes in relative proportions of the most dominant taxa, while a decrease in taxonomic richness was less pronounced compared to sedaDNA. Our results show the advantages of using sedaDNA in combination with palynological analyses when macrofossils are rarely preserved. The high resolution of the sedaDNA record provides a detailed picture of the taxonomic composition of plant-derived organic matter throughout the core, and palynological analyses prove valuable by allowing for inferences of regional environmental conditions.}, language = {en} } @book{OPUS4-5773, title = {Klimapolitik International}, editor = {Kleinw{\"a}chter, Kai}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-173-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-58354}, publisher = {Universit{\"a}t Potsdam}, pages = {100}, year = {2012}, abstract = {Der Klimawandel birgt globale Risiken. Dies ist weithin anerkannt. Umstritten ist die Frage, wie diesen Gefahren zu begegnen ist. 14 Jahre nach Kyoto ist klar: Klimapolitik ist Interessenpolitik. Das zeigte zuletzt die UN-Klimakonferenz 2011 in Durban mit ihren unverbindlichen Ergebnissen. In diesem Sammelband analysieren Experten Ursachen f{\"u}r das Scheitern der vergangenen Klima-Konferenzen und Konsequenzen f{\"u}r die k{\"u}nftige Klimapolitik. Insbesondere geht es um die Politik der Akteure China und Indien, um die Rolle der NGOs und die Klimafrage in der Entwicklungspolitik. Zugleich wird die deutsche Klimapolitik diskutiert und die Politik Brandenburgs von der verantwortlichen Ministerin vorgestellt.}, language = {de} }