@phdthesis{Marquart2019,
  author    = {Marquart, Arnim},
  title     = {Feedbacks between macropores and soil water infiltration in semi-arid savanna systems},
  pages     = {146},
  year      = {2019},
  language  = {en}
}
@phdthesis{Bamberg2014,
  author    = {Bamberg, Marlene},
  title     = {Planetary mapping tools applied to floor-fractured craters on Mars},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-72104},
  school      = {Universit{\"a}t Potsdam},
  year      = {2014},
  abstract  = {Planetary research is often user-based and requires considerable skill, time, and effort. Unfortunately, self-defined boundary conditions, definitions, and rules are often not documented or not easy to comprehend due to the complexity of research. This makes a comparison to other studies, or an extension of the already existing research, complicated. Comparisons are often distorted, because results rely on different, not well defined, or even unknown boundary conditions. The purpose of this research is to develop a standardized analysis method for planetary surfaces, which is adaptable to several research topics. The method provides a consistent quality of results. This also includes achieving reliable and comparable results and reducing the time and effort of conducting such studies. A standardized analysis method is provided by automated analysis tools that focus on statistical parameters. Specific key parameters and boundary conditions are defined for the tool application. The analysis relies on a database in which all key parameters are stored. These databases can be easily updated and adapted to various research questions. This increases the flexibility, reproducibility, and comparability of the research. However, the quality of the database and reliability of definitions directly influence the results. To ensure a high quality of results, the rules and definitions need to be well defined and based on previously conducted case studies. The tools then produce parameters, which are obtained by defined geostatistical techniques (measurements, calculations, classifications). The idea of an automated statistical analysis is tested to proof benefits but also potential problems of this method. In this study, I adapt automated tools for floor-fractured craters (FFCs) on Mars. These impact craters show a variety of surface features, occurring in different Martian environments, and having different fracturing origins. They provide a complex morphological and geological field of application. 433 FFCs are classified by the analysis tools due to their fracturing process. Spatial data, environmental context, and crater interior data are analyzed to distinguish between the processes involved in floor fracturing. Related geologic processes, such as glacial and fluvial activity, are too similar to be separately classified by the automated tools. Glacial and fluvial fracturing processes are merged together for the classification. The automated tools provide probability values for each origin model. To guarantee the quality and reliability of the results, classification tools need to achieve an origin probability above 50 \%. This analysis method shows that 15 \% of the FFCs are fractured by intrusive volcanism, 20 \% by tectonic activity, and 43 \% by water \& ice related processes. In total, 75 \% of the FFCs are classified to an origin type. This can be explained by a combination of origin models, superposition or erosion of key parameters, or an unknown fracturing model. Those features have to be manually analyzed in detail. Another possibility would be the improvement of key parameters and rules for the classification. This research shows that it is possible to conduct an automated statistical analysis of morphologic and geologic features based on analysis tools. Analysis tools provide additional information to the user and are therefore considered assistance systems.},
  language  = {en}
}
@phdthesis{Fuerstenau2008,
  author    = {F{\"u}rstenau, Cornelia},
  title     = {The impact of silvicultural strategies and climate change on carbon sequestration and other forest ecosystem functions},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27657},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {Forests are a key resource serving a multitude of functions such as providing income to forest owners, supplying industries with timber, protecting water resources, and maintaining biodiversity. Recently much attention has been given to the role of forests in the global carbon cycle and their management for increased carbon sequestration as a possible mitigation option against climate change. Furthermore, the use of harvested wood can contribute to the reduction of atmospheric carbon through (i) carbon sequestration in wood products, (ii) the substitution of non-wood products with wood products, and (iii) through the use of wood as a biofuel to replace fossil fuels. Forest resource managers are challenged by the task to balance these multiple while simultaneously meeting economic requirements and taking into consideration the demands of stakeholder groups. Additionally, risks and uncertainties with regard to uncontrollable external variables such as climate have to be considered in the decision making process. In this study a scientific stakeholder dialogue with forest-related stakeholder groups in the Federal State of Brandenburg was accomplished. The main results of this dialogue were the definition of major forest functions (carbon sequestration, groundwater recharge, biodiversity, and timber production) and priority setting among them by the stakeholders using the pair-wise comparison technique. The impact of different forest management strategies and climate change scenarios on the main functions of forest ecosystems were evaluated at the Kleinsee management unit in south-east Brandenburg. Forest management strategies were simulated over 100 years using the forest growth model 4C and a wood product model (WPM). A current climate scenario and two climate change scenarios based on global circulation models (GCMs) HadCM2 and ECHAM4 were applied. The climate change scenario positively influenced stand productivity, carbon sequestration, and income. The impact on the other forest functions was small. Furthermore, the overall utility of forest management strategies were compared under the priority settings of stakeholders by a multi-criteria analysis (MCA) method. Significant differences in priority setting and the choice of an adequate management strategy were found for the environmentalists on one side and the more economy-oriented forest managers of public and private owned forests on the other side. From an ecological perspective, a conservation strategy would be preferable under all climate scenarios, but the business as usual management would also fit the expectations under the current climate. In contrast, a forest manager in public-owned forests or a private forest owner would prefer a management strategy with an intermediate thinning intensity and a high share of pine stands to enhance income from timber production while maintaining the other forest functions. The analysis served as an example for the combined application of simulation tools and a MCA method for the evaluation of management strategies under multi-purpose and multi-user settings with changing climatic conditions. Another focus was set on quantifying the overall effect of forest management on carbon sequestration in the forest sector and the wood industry sector plus substitution effects. To achieve this objective, the carbon emission reduction potential of material and energy substitution (Smat and Sen) was estimated based on a literature review. On average, for each tonne of dry wood used in a wood product substituting a non-wood product, 0.71 fewer tonnes of fossil carbon are emitted into to the atmosphere. Based on Smat and Sen, the calculation of the carbon emission reduction through substitution was implemented in the WPM. Carbon sequestration and substitution effects of management strategies were simulated at three local scales using the WPM and the forest growth models 4C (management unit level) or EFISCEN (federal state of Brandenburg and Germany). An investigation was conducted on the influence of uncertainties in the initialisation of the WPM, Smat, and basic conditions of the wood product sector on carbon sequestration. Results showed that carbon sequestration in the wood industry sector plus substitution effects exceeded sequestration in the forest sector. In contrast to the carbon pools in the forest sector, which acted as sink or source, the substitution effects continually reduced carbon emission as long as forests are managed and timber is harvested. The main climate protection function was investigated for energy substitution which accounted for about half of the total carbon sequestration, followed by carbon storage in landfills. In Germany, the absolute annual carbon sequestration in the forest and wood industry sector plus substitution effects was 19.9 Mt C. Over 50 years the wood industry sector contributed 70\% of the total carbon sequestration plus substitution effects.},
  language  = {en}
}
@phdthesis{Vorogushyn2008,
  author    = {Vorogushyn, Sergiy},
  title     = {Analysis of flood hazard under consideration of dike breaches},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27646},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {River reaches protected by dikes exhibit high damage potential due to strong value accumulation in the hinterland areas. While providing an efficient protection against low magnitude flood events, dikes may fail under the load of extreme water levels and long flood durations. Hazard and risk assessments for river reaches protected by dikes have not adequately considered the fluvial inundation processes up to now. Particularly, the processes of dike failures and their influence on the hinterland inundation and flood wave propagation lack comprehensive consideration. This study focuses on the development and application of a new modelling system which allows a comprehensive flood hazard assessment along diked river reaches under consideration of dike failures. The proposed Inundation Hazard Assessment Model (IHAM) represents a hybrid probabilistic-deterministic model. It comprises three models interactively coupled at runtime. These are: (1) 1D unsteady hydrodynamic model of river channel and floodplain flow between dikes, (2) probabilistic dike breach model which determines possible dike breach locations, breach widths and breach outflow discharges, and (3) 2D raster-based diffusion wave storage cell model of the hinterland areas behind the dikes. Due to the unsteady nature of the 1D and 2D coupled models, the dependence between hydraulic load at various locations along the reach is explicitly considered. The probabilistic dike breach model describes dike failures due to three failure mechanisms: overtopping, piping and slope instability caused by the seepage flow through the dike core (micro-instability). The 2D storage cell model driven by the breach outflow boundary conditions computes an extended spectrum of flood intensity indicators such as water depth, flow velocity, impulse, inundation duration and rate of water rise. IHAM is embedded in a Monte Carlo simulation in order to account for the natural variability of the flood generation processes reflected in the form of input hydrographs and for the randomness of dike failures given by breach locations, times and widths. The model was developed and tested on a ca. 91 km heavily diked river reach on the German part of the Elbe River between gauges Torgau and Vockerode. The reach is characterised by low slope and fairly flat extended hinterland areas. The scenario calculations for the developed synthetic input hydrographs for the main river and tributary were carried out for floods with return periods of T = 100, 200, 500, 1000 a. Based on the modelling results, probabilistic dike hazard maps could be generated that indicate the failure probability of each discretised dike section for every scenario magnitude. In the disaggregated display mode, the dike hazard maps indicate the failure probabilities for each considered breach mechanism. Besides the binary inundation patterns that indicate the probability of raster cells being inundated, IHAM generates probabilistic flood hazard maps. These maps display spatial patterns of the considered flood intensity indicators and their associated return periods. Finally, scenarios of polder deployment for the extreme floods with T = 200, 500, 1000 were simulated with IHAM. The developed IHAM simulation system represents a new scientific tool for studying fluvial inundation dynamics under extreme conditions incorporating effects of technical flood protection measures. With its major outputs in form of novel probabilistic inundation and dike hazard maps, the IHAM system has a high practical value for decision support in flood management.},
  language  = {en}
}
@phdthesis{Wattenbach2008,
  author    = {Wattenbach, Martin},
  title     = {The hydrological effects of changes in forest area and species composition in the federal state of Brandenburg, Germany},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27394},
  school      = {Universit{\"a}t Potsdam},
  year      = {2008},
  abstract  = {This thesis aims to quantify the human impact on the natural resource water at the landscape scale. The drivers in the federal state of Brandenburg (Germany), the area under investigation, are land-use changes induced by policy decisions at European and federal state level. The water resources of the federal state are particularly sensitive to changes in land-use due to low precipitation rates in the summer combined with sandy soils and high evapotranspiration rates. Key elements in landscape hydrology are forests because of their unique capacity to transport water from the soil to the atmosphere. Given these circumstances, decisions made at any level of administration that may have effects on the forest sector in the state are critical in relation to the water cycle. It is therefore essential to evaluate any decision that may change forest area and structure in such a sensitive region. Thus, as a first step, it was necessary to develop and implement a model able to simulate possible interactions and feedbacks between forested surfaces and the hydrological cycle at the landscape scale. The result is a model for simulating the hydrological properties of forest stands based on a robust computation of the temporal and spatial LAI (leaf area index) dynamics. The approach allows the simulation of all relevant hydrological processes with a low parameter demand. It includes the interception of precipitation and transpiration of forest stands with and without groundwater in the rooting zone. The model also considers phenology, biomass allocation, as well as mortality and simple management practices. It has been implemented as a module in the eco-hydrological model SWIM (Soil and Water Integrated Model). This model has been tested in two pre-studies to verify the applicability of its hydrological process description for the hydrological conditions typical for the state. The newly implemented forest module has been tested for Scots Pine (Pinus sylvestris) and in parts for Common Oak (Quercus robur and Q. petraea) in Brandenburg. For Scots Pine the results demonstrate a good simulation of annual biomass increase and LAI in addition to the satisfactory simulation of litter production. A comparison of the simulated and measured data of the May sprout for Scots pine and leaf unfolding for Oak, as well as the evaluation against daily transpiration measurements for Scots Pine, does support the applicability of the approach. The interception of precipitation has also been simulated and compared with weekly observed data for a Scots Pine stand which displays satisfactory results in both the vegetation periods and annual sums. After the development and testing phase, the model is used to analyse the effects of two scenarios. The first scenario is an increase in forest area on abandoned agricultural land that is triggered by a decrease in European agricultural production support. The second one is a shift in species composition from predominant Scots Pine to Common Oak that is based on decisions of the regional forestry authority to support a more natural species composition. The scenario effects are modelled for the federal state of Brandenburg on a 50m grid utilising spatially explicit land-use patterns. The results, for the first scenario, suggest a negative impact of an increase in forest area (9.4\% total state area) on the regional water balance, causing an increase in mean long-term annual evapotranspiration of 3.7\% at 100\% afforestation when compared to no afforestation. The relatively small annual change conceals a much more pronounced seasonal effect of a mean long-term evapotranspiration increase by 25.1\% in the spring causing a pronounced reduction in groundwater recharge and runoff. The reduction causes a lag effect that aggravates the scarcity of water resources in the summer. In contrast, in the second scenario, a change in species composition in existing forests (29.2\% total state area) from predominantly Scots Pine to Common Oak decreases the long-term annual mean evapotranspiration by 3.4\%, accompanied by a much weaker, but apparent, seasonal pattern. Both scenarios exhibit a high spatial heterogeneity because of the distinct natural conditions in the different regions of the state. Areas with groundwater levels near the surface are particularly sensitive to changes in forest area and regions with relatively high proportion of forest respond strongly to the change in species composition. In both cases this regional response is masked by a smaller linear mean effect for the total state area. Two critical sources of uncertainty in the model results have been investigated. The first one originates from the model calibration parameters estimated in the pre-study for lowland regions, such as the federal state. The combined effect of the parameters, when changed within their physical meaningful limits, unveils an overestimation of the mean water balance by 1.6\%. However, the distribution has a wide spread with 14.7\% for the 90th percentile and -9.9\% for the 10th percentile. The second source of uncertainty emerges from the parameterisation of the forest module. The analysis exhibits a standard deviation of 0.6 \% over a ten year period in the mean of the simulated evapotranspiration as a result of variance in the key forest parameters. The analysis suggests that the combined uncertainty in the model results is dominated by the uncertainties of calibration parameters. Therefore, the effect of the first scenario might be underestimated because the calculated increase in evapotranspiration is too small. This may lead to an overestimation of the water balance towards runoff and groundwater recharge. The opposite can be assumed for the second scenario in which the decrease in evapotranspiration might be overestimated.},
  language  = {en}
}
@phdthesis{Saiger2007,
  author    = {Saiger, Peter Paul},
  title     = {Entwicklung, Implementierung und Erprobung eines planetaren Informationssystems auf Basis von ArcGIS},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15877},
  school      = {Universit{\"a}t Potsdam},
  year      = {2007},
  abstract  = {Mit der Entwicklung der modernen Raumfahrt Mitte der 60er-Jahre des zwanzigsten Jahrhunderts und der Eroberung des Weltraums brach eine neue Epoche der bis dato auf Beobachtungen mit dem Teleskop gest{\"u}tzten planetaren Forschung an. W{\"a}hrend des Wettrennens um die technologische F{\"u}hrerschaft im All zur Zeit des Kalten Krieges war das erste Ziel die Entsendung von Satelliten zur Erdbeobachtung, denen aber schon bald Sonden zum Mond und den benachbarten Planeten folgten. Diese Missionen lieferten eine enorme F{\"u}lle von Informationen in Form von Bildern und Messergebnissen in unterschiedlichen Datenformaten. Diese galt und gilt es zu strukturieren, zu verwalten, zu aktualisieren und zu interpretieren. F{\"u}r die Interpretation terrestrischer Daten werden geographische Informationssysteme (GIS) hinzugezogen, die jedoch f{\"u}r planetare Anwendungen aufgrund unterschiedlicher Voraussetzungen nicht ohne weiteres eingesetzt werden k{\"o}nnen. Daher wurde im Rahmen dieser Arbeit die f{\"u}r die Verwaltung von geographischen Daten der Erdfernerkundung kommerziell erh{\"a}ltliche Software ArcGIS Desktop 9.0 / 9.1 (ESRI) mit eigenen Programmen und Modulen f{\"u}r die Planetenforschung angepasst. Diese erm{\"o}glichen die Aufbereitung und den Import planetarer Bild- und Textinformation in die kommerzielle Software. Zus{\"a}tzlich wurde eine planetare Datenbank zur Speicherung und zentralen Verwaltung der Informationen aufgebaut. Die im Rahmen dieser Arbeit entwickelten Softwarekomponenten erm{\"o}glichen die schnelle und benutzerfreundliche Aufbereitung der in der Datenbank gehaltenen Informationen und das Auslesen in Dateiformate, die f{\"u}r geographische Informationssysteme geeignet sind. Des Weiteren wurde eine „Werkzeugleiste" f{\"u}r ArcGIS entwickelt, die das Arbeiten mit planetaren Datens{\"a}tzen betr{\"a}chtlich beschleunigt und vereinfacht. Sie beinhaltet auch Module zur wissenschaftlichen Interpretation der planetaren Informationen, wie beispielsweise der Berechnung der Oberfl{\"a}chenrauigkeit der Marsoberfl{\"a}che inklusive der fl{\"a}chendeckenden Kalibrierung der Eingangs-Basisdaten. Exemplarisch konnte gezeigt werden, dass das Verfahren eine verbesserte Berechnung der Oberfl{\"a}chenrauigkeit erm{\"o}glicht, als bisher angewandte Ans{\"a}tze. Zudem wurde eine auf ArcGIS basierende Prozesskette zur Berechnung von hierarchischen Flussnetzen entwickelt und erprobt. Das terrestrische Beispiel, die Analyse eines Abflusssystems auf Island, zeigte eine sehr große {\"U}bereinstimmung der errechneten Gew{\"a}ssernetze mit den morphologischen Gegebenheiten vor Ort. Daraus ließ sich eine hohe Genauigkeit der mit demselben Ansatz errechneten Gew{\"a}ssernetze auf dem Mars ableiten. Auf der Grundlage der in dieser Arbeit entwickelten Programme und Module lassen sich auch Daten zuk{\"u}nftiger Missionen aufbereiten und in ein solches System einbinden, um diese mit eigenen Ans{\"a}tzen zu verwalten, zu aktualisieren und f{\"u}r neue wissenschaftliche Fragestellungen perfekt anzupassen, einzusetzen und zu pr{\"a}sentieren, um so neue wissenschaftliche Erkenntnisse in der Planetenforschung zu gewinnen.},
  language  = {de}
}
@phdthesis{Voss2007,
  author    = {Voß, Anja},
  title     = {Untersuchung und Modellierung der Stickstoff- und Phosphorumsatz- und Transportprozesse in mesoskaligen Einzugsgebieten des Tieflandes am Beispiel von Nuthe, Hammerfließ und Stepenitz},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-15481},
  school      = {Universit{\"a}t Potsdam},
  year      = {2007},
  abstract  = {Ziel dieser Arbeit war es, die Stickstoff- und Phosphorprozesse im nordostdeutschen Tiefland detailliert zu untersuchen und Handlungsoptionen hinsichtlich der Landnutzung zur nachhaltigen Steuerung der Stickstoff- und Phosphoreintr{\"a}ge in die Fließgew{\"a}sser aufzuzeigen. Als Grundvoraussetzung f{\"u}r die Modellierung des N{\"a}hrstoffhaushaltes mussten zun{\"a}chst die hydrologischen Prozesse und die Abfl{\"u}sse f{\"u}r die Einzugsgebiete validiert werden. Daf{\"u}r wurde in dieser Arbeit das {\"o}kohydrologische Modell SWIM verwendet. Die Abflussmodellierung umfasste den Zeitraum 1991 - 2000. Die Ergebnisse dazu zeigen, dass SWIM in der Lage war, die hydrologischen Prozesse in den Untersuchungsgebieten ad{\"a}quat wiederzugeben. Auf der Grundlage der Modellierung des Wasserhaushaltes wurden mit SWIM die Stoffumsatzprozesse f{\"u}r den Zeitraum 1996 - 2000 simuliert. Um dabei besonders das Prozessgeschehen im Tiefland zu ber{\"u}cksichtigen, war die Erweiterung von SWIM um einen Ammonium-Pool mit dessen Umsatzprozessen erforderlich. Außerdem wurde der Prozess der N{\"a}hrstoffversickerung so erg{\"a}nzt, dass neben Nitrat auch Ammonium und Phosphat durch das gesamte Bodenprofil verlagert und {\"u}ber die Abflusskomponenten zum Gebietsauslass transportiert werden k{\"o}nnen. Mit diesen Modellerweiterungen konnten die Stickstoff und Phosphorprozesse in den Untersuchungsgebieten gut abgebildet werden. Mit dem so validierten Modell wurden weitere Anwendungen erm{\"o}glicht. N{\"a}hrstoffsimulationen f{\"u}r den Zeitraum 1981 bis 2000 dienten der Untersuchung des abnehmenden Trends in den N{\"a}hrstoffkonzentrationen der Nuthe. Die Untersuchungsergebnisse lassen deutlich erkennen, dass sich die Konzentrationen nach 1990 haupts{\"a}chlich auf Grund der Reduzierung der Eintr{\"a}ge aus punktf{\"o}rmigen Quellen und Rieselfeldern verringert haben. Weitere Modellrechnungen zur Herkunft der N{\"a}hrstoffe haben ergeben, dass Nitrat {\"u}berwiegend aus diffusen Quellen, Ammonium und Phosphat dagegen aus punktf{\"o}rmigen Quellen stammen. Als besonders sensitiv auf die Modellergebnisse haben sich die Parameter zu Landnutzung und -management und die Durchwurzelungstiefe der Pflanzen herausgestellt. Abschließend wurden verschiedene Landnutzungsszenarien angewendet. Die Ergebnisse zu den Szenariorechnungen zeigen, dass fast alle vorgegebenen Landnutzungsszenarien zu einer Verringerung der Stickstoff- bzw. Phosphoremissionen f{\"u}hrten. Die Anwendung von Szenarien, die alle relevanten Zielvorgaben und Empfehlungen zum Ressourcenschutz ber{\"u}cksichtigen, zeigen die gr{\"o}ßten Ver{\"a}nderungen.},
  language  = {de}
}