12 documents found

Dissertation
All rights reserved
2019

Regional groundwater representation by coupling the mesoscale Hydrologic...

Groundwater is the source of approximately twenty percent of the worlds freshwater supply. It is also one of the most important sources of water for irrigation. However, groundwater has been over-used and polluted in many places in the world. Climate change and saltwater intrusion are threatening groundwater...
Dissertation
All rights reserved
2017

Soil moisture droughts in Germany : retrospective analysis, parametric uncerta ...

Droughts are worldwide the second most severe natural disaster beside floods. In Europe, droughts are the costliest natural disasters with average expenses of 621 million EUR per event. The last severe drought event took place in 2003. It induced an agro-economic loss of 1.5 billion EUR in Germany alone....
Dissertation
All rights reserved
2017

Long-term drainage effects on carbon fluxes of an Arctic permafrost ecosystem

Permafrost landscapes in the Northern high latitudes with their massive organic carbon stocks are critically important for the global carbon cycle. Large uncertainties in the sustainability of these carbon pools under future climate conditions persist, caused by limited understanding of permafrost carbon...
Dissertation
All rights reserved
2017

Innovative techniques for the characterization and interpretation of coastal...

Aquifers are intrinsically heterogeneous, but the interpretation of pumping tests to estimate hydraulic aquifer parameters, such as transmissivity and storativity, is commonly performed under the assumption of homogeneity, by utilizing Theis equation. This yields interpreted parameters whose relation...
Dissertation
All rights reserved
2016-05-31

Canopy structure and the impact of drought on a Quercus suber L. woodland...

The thesis covers two topics, a performance evaluation of indirect leaf area index L and gap probability Pgap observation with the new digital cover photography DCP with special focus on the application in sparse canopies and the analysis of drought effects on water / carbon fluxes in a typical Mediterranean...
Dissertation
All rights reserved
2016

Evaluation and disaggregation of climate model outputs for european drought...

Landwirtschaftliche Dürren führen zu hohen sozialen und wirtschaftlichen Schäden. Die Auswirkungen dieser Extremereignisse können mit der Hilfe von einem saisonalen Vorhersagesystem, welches Dürren mehrere Monate im Voraus prognostiziert, abgeschwächt werden. Das Vorhersagesystem, welches in dieser Arbeit...
Dissertation
2014-11-13

Sensitivity and uncertainty analysis of environmental models

Die vorliegende Arbeit behandelt die Thematik der numerischen Evaluierung von Umweltmodellausgaben hinsichtlich ihrer Sensitivität und Unsicherheiten, wobei Methoden nach dem Stand der Technik angewandt, erweitert bzw. neue Verfahren entwickelt wurden. Im ersten Teil der Arbeit geht es im Kern darum,...
Dissertation
2014-07-11

Does ecosystem diversity affect soil hydraulic properties? : investigation of ...

The present thesis aims to evaluate the relationships between soil hydraulic properties and earthworms, plant community, soil structural parameters, soil texture, and soil moisture in the frame of a long-term grassland biodiversity experiment, the so called Jena Experiment. Hydraulic properties such...
Dissertation
All rights reserved
2014-02-25

Impact of aqifer heterogeneity on subsurface flow and salt transport at...

More than 70% of the German population rely on groundwater as their daily drinking water supply. Hence, the understanding of processes like fluid flow and solute transport in porous media are of broad relevance. However, subsurface hydrology faces two problems. On the one hand, information about the...
Dissertation
2012-06-28

Influence of vegetation on water fluxes at the ground level in a semi-arid...

Pflanzen beeinflussen in großem Maß die Wasserbilanz, insbesondere in ariden und semiariden Gebieten. Der wichtigste Einfluss ist dabei die Transpiration der Pflanzen, aber auch abwärts gerichtete Flüsse unterliegen starken Veränderungen, vor allem der Bestandsniederschlag, also der Teil des Wassers...
Dissertation
All rights reserved
2012-02-15

Influence of plant water relation on ecosystem function under water stress

In this thesis we study the interaction between biodiversity and near surface groundwater, during water stress by first characterizing the study area in terms of groundwater and soil water geochemical processes and hydrogeology in a large-scale biodiversity experiment. We also investigated the spatial...
Dissertation
2011-06-14

Scaling Haline Flows in Saturated Heterogeneous Formations

Density-driven flows occur in deep aquifers due to temperature differences, in coastal aquifers due to salt mass differences but also in contaminant migration at refuse dumps. Its relevance therefore cuts across many applications like exploitation of geothermal energy resources, oil recoverly from...