Die Kenntnis von hydraulischen Durchlässigkeiten wie auch von Wasser- und Verunreinigungsfluxen in porösen Grundwasserleitern ist von großer Bedeutung in vielen hydrogeologischen Belangen wie z.B. Beregnung, Versickerung, quantitative und qualitative Wasserwirtschaft, Risikoabschätzung bei Verunreinigungen, usw. Derzeit ist keine theoretisch gut fundierte Methode zur Messung horizontaler und vertikaler Durchlässigkeiten in der gesättigten Zone verfügbar und Methoden zur Messung von gesättigten Durchlässigkeiten in der ungesättigten Zone sind beschränkt, zeitaufwendig und fallweise unzuverlässig. Außerdem ist gegenwärtig keine Methode zur direkten Messung vertikaler Wasser- und Verunreinigunsfluxe in porösen Grundwasserleitern oder am Übergang zwischen Grund- und Oberflächengewässern bekannt. Das dargelegte Projekt basiert auf der Entwicklung einer exakten Lösung des Strömungsfeldes für das Ein- oder Auspumpen von Wasser durch eine beliebige Anzahl von unterschiedlichen Filterabschnitten entlang eines ansonsten undurchlässigen Filterrohres bei verschiedenen Randbedingungen. Diese Lösung erlaubt die Ermittlung von Formfaktoren der Strömungsfelder, die zur Berechnung hydraulischer Durchlässigkeiten aus Einpressversuchen nötig sind. Die derzeit angewendeten Formeln können mit der genauen Lösung verglichen und der Einfluss anisotroper Durchlässigkeiten kann miteinbezogen werden. Eine doppelfiltrige Rammsonde wird zur bohrlochfreien Messung horizontaler und vertikaler Durchlässigkeiten in verschiedenen Tiefen unter dem Grundwasserspiegel vogeschlagen. Der Test besteht aus zwei Teilen: (1) Einpressen durch beide Filterabschnitte und (2) Zirkulation zwischen den Filtern. Die gleiche Sondenkonfiguration wird für die direkte und gleichzeitige Messung lokaler, kumulativer, vertikaler Wasser- und Verunreinigungsfluxe nach dem passiven Fluxmeter-Prinzip vorgeschlagen. Ohne zu pumpen werden die beiden Filterabschnitte hiebei durch eine mit Tracern geladene Filtersäule hydraulisch verbunden. Der vertikale Gradient im Testbereich treibt einen Fluss durch den Filter, der kontinuierlich Tracer auswäscht und Verunreinigungen im Filter hinterlässt. Aus der Analyse des Filtermaterials zur Bestimmung der Tracer- und Verunreinigungsmengen nach dem Test werden mit Kenntnis des Strömungsfeldes um die Sonde die Wasser- und Verunreinigungsfluxe bestimmt. Eine kegelförmige, doppelfiltrige Rammsonde wird weiters vorgeschlagen, um gesättigte Durchlässigkeiten sowohl über als auch unter dem Grundwasserspiegel direkt messen zu können. Die Methode basiert auf stationärer, gesättigt/ungesättigt gekoppelter Strömung aus kugelförmigen Hohlräumen. Die Möglichkeit einer transienten einfiltrigen Methode und einer Methode zur Messung anisotroper Durchlässigkeiten wird beurteilt. Die vorgeschlagenen theoretischen Konzepte werden ausgearbeitet und anhand von Laborversuchen überprüft.
Egypt passed a revolution and changed its political system, but many problems are still lacking a solution. Especially in the field of water the North African country has to face many challenges. Most urgent are strategies to manage the limited water resources. About 80% of the available water resources are consumed for agriculture and the rest are for domestic and industrial activities. The management of these resources is inefficient and a huge amount of fresh water is discarded. The shortage of water supply will definitely influence the economic and cultural development of Egypt. In 2010, Egypt was ranked number 8 out of 165 nations reviewed in the so-called Water Security Risk Index published by Maplecroft. The ranking of each country in the index depends mainly on four key factors, i.e. access to improved drinking water and sanitation, the availability of renewable water and the reliance on external supplies, the relationship between available water and supply demands, and the water dependency of each countrys economy. Based on this study, the situation of water in Egypt was identified as extremely risky. A number of programs and developed strategies aiming to efficiently manage the usage of water resources have been carried out in the last few years by the Egyptian Government. But all these activities, however, require the availability of trained and well-educated individuals in water technology fields. Unfortunately, the number of water science graduates are decreasing and also there are few teaching and training courses for water science offered in Egypt. However, there is still a demand for several well-structured and international programs to fill the gap and provide the Egyptian fresh graduates with the adequate and up-to-date theoretical and practical knowledge available for water technology. IWaTec is designed to fill parts of this gap.
Das Thema zeigt die Lage und weitere Angaben von Erdgas- bzw. Geothermie-Bohrungen in Niedersachsen, in denen Frac-Maßnahmen durchgeführt wurden. Hydraulic Fracturing (Fracking) ist eine Technik, mit der Gesteine behandelt werden, um künstliche Fließwege zu erzeugen. Dabei werden in den Gesteinen durch Einpressen einer Frac-Flüssigkeit Risse erzeugt. Das Gestein wird aufgebrochen (engl.: to fracture = aufbrechen) und die bis zu mehrere hundert Meter langen, schmalen Risse werden mit Stützkörpern aus Spezialsanden verfüllt, damit sie sich nicht wieder schließen. Bei der Anwendung der Frac-Technik in der Erdgasförderung soll die Förderrate einer Erdgasbohrung erhöht werden.
Das Thema zeigt die Lage und weitere Angaben von Erdgas- bzw. Geothermie-Bohrungen in Niedersachsen, in denen Frac-Maßnahmen durchgeführt wurden. Hydraulic Fracturing (Fracking) ist eine Technik, mit der Gesteine behandelt werden, um künstliche Fließwege zu erzeugen. Dabei werden in den Gesteinen durch Einpressen einer Frac-Flüssigkeit Risse erzeugt. Das Gestein wird aufgebrochen (engl.: to fracture = aufbrechen) und die bis zu mehrere hundert Meter langen, schmalen Risse werden mit Stützkörpern aus Spezialsanden verfüllt, damit sie sich nicht wieder schließen. Bei der Anwendung der Frac-Technik in der Erdgasförderung soll die Förderrate einer Erdgasbohrung erhöht werden.
Black carbon (BC) residues from the incomplete combustion of vegetation and fossil fuels are ubiquitous in soil, sediment and water. Due to its stability, BC is an important component of the slow cycling global carbon pool. Analysis of BC in environmental matrices such as soils and sediments is complicated by its diverse nature. Sediments are the quantitatively most important sink in the global black carbon cycle and represent archives of BC deposition on local and regional scales, but the identification and apportionment of the BC sources (fossil fuel combustion versus vegetation fires) remain unclear to date. Benzene polycarboxylic acids (BPCA) are molecular markers specific for BC and are used to measure quantity and quality of BC. The method provides information about the degree of condensation and allows characterization of different forms of BC (e.g. charcoal, soot). Recent advances in BPCA analysis improved the method in terms of sample preparation and made analyses faster and more accurate. Compound specific radiocarbon (14C) dating is a powerful tool in geochemistry and archaeological sciences to trace the fate of specific molecules in soils and sediments. Up to now, 14C measurements are inaccurate for BC, as established methods measure 14C contents of oxidation resistant bulk carbon. In the proposed research project, I will follow a novel approach for BPCA separation with subsequent determination of its 14C contents. This technique will allow to precisely estimate the apportionment of sources of BC found in sediments and the age of black carbon in soils. In this project I will take advantage of an existing set of well-dated lake sediment samples. These sediment cores feature undisturbed lamination, thus providing a high-resolution record of BC depositions over more than two centuries. Analyzing this unique sample set, the qualitative and quantitative information yielded by the BPCA method and the novel approach for radiocarbon dating of BC molecular markers will be used to construct a historical record of black carbon emissions. The data will be used to apportion the measured BC concentrations to either fossil fuel or biomass burning since pre-industrial times and to identify the type of BC being preferentially preserved in aquatic sediments. The outcome of the project will help to elucidate the environmental fate of BC and will be an important contribution to the accurate calculation of a global BC budget.
The current processes of global change are an enormous challenge for societies worldwide. The SASSCAL is a joint initiative of Angola, Botswana, Namibia, South Africa, Zambia, and Germany, responding to the challenges of global change. Aim and Scope: SASSCAL will improve the capacities to provide sound science-based solutions for current problems and future risks in the region, in particular regarding climate change and the associated demands concerning land management practices of local players. To this end, the centre will contribute to strengthening existing and developing new capacities for application-oriented scientific research and science-policy consultations on climate change, adapted land-use and sustainable development in the region. SASSCAL will support national, regional and local institutions and service providers to develop relevant advisory and implementation skills. It will have a regional scope and the work of the Centre will be defined in partnership with the respective scientific communities, the users of science products, policy-makers, and decision-makers. Research: SASSCAL intends to cover a variety of research issues in state-of-the-art climate change and land management research, responding to the regional definition of needs and demands. The task of the ISOE project team is to analyse to what extent water-related vulnerabilities and risks for the population and ecosystems are developing within the context of global change and how these might conceivably be reduced. Research approach: Many natural and social processes mutually influence water resources in the southern part of Africa. Climate change and changes in land use, as well as population and economic growth act as localised forms of global change on the current and future state of the resource and as such influence peoples living conditions. The project team is developing a vulnerability and risk analysis for the catchment area of the Cuvelai-Basin in northern Namibia and southern Angola. First the 'status quo and expected trends in patterns of water demand are being studied, differentiated according to spatial and social characteristics and with the help of social-empirical surveys, consultations with experts and mapping. Using this as a starting point, researchers calculate water demand and availability in order to discover the water supplys vulnerabilities and risks for the population and ecosystems. The aim is to identify areas of relevance for decision-makers which are particularly threatened by supply gaps and their consequences (hot spot areas). Next the researchers will be developing supportive measures for an adapted and integrated management of water resources. usw.
A very high percentage of the agronomically used area in Switzerland is covered by grasslands. This land use type is present at various altitudes (up to alpine regions), where environmental conditions, community structure, nutrient dynamics and productivity vary in a wide range. Results obtained during phase 1 of the NCCR Climate, but also by other research groups globally, lead to the conclusion that - besides an increase in mean temperature - temperature variability will increase considerably in Central Europe (Schär et al. 2004). However, the response of entire grassland systems to drought and heat remains unclear. Many earlier studies focused only on soil or vegetation (often only above-ground; e.g. Pfisterer and Schmid 2002), but did not consider the entire ecosystem with its interactions between different ecosystem components (e.g., Kahmen et al. 2004). We know that heat affects photosynthesis and - as a consequence - net carbon fluxes and plant productivity, as reported for example for oak (NCCR Phase 1; Haldimann and Feller 2004). How climatic factors affect above- and below-ground processes in temperate grasslands and how to implement safe management strategies to mitigate changes is less known. We will focus on drought and heat effects on managed grasslands. In grasslands, much of the biological activity and resource turnover happens below-ground; here carbon stocks can be as large as the annual above-ground harvested biomass. However, harvest and grazing typically take place above a certain height (typically 3 - 7 cm above ground), leaving behind large quantities of organic carbon as stubble (standing living and dead biomass) and litter. While the plant biomass above the cutting/grazing height is important for agricultural purposes (yield), biomass below this height is relevant for regrowth after cutting/grazing, for the development and maintenance of the root system and therefore resource use, for the transfer but also loss of carbon, nitrogen and other nutrients to the soil, and for soil carbon sequestration (Avice et al. 1996). The quantities and contributions of these various components to the total ecosystem depend on the allocation of assimilates and nutrients in the plants, on the metabolic activities and on the redistribution during senescence (Avice et al. 1996, Jeuffroy et al. 2002) as well as on microbial activities in the soil. The so far poorly quantified transfer rate for carbon from above-ground litter to below-ground organic matter is a key issue in this context (Lal 2004). In addition, all these processes are influenced by climatic and environmental conditions. For example, Palta and Gregory (1997) reported that wheat allocated relatively more assimilates to the roots under limited water conditions compared to adequate soil water. Kahmen et al. (2004) found stable above-ground productivity but increased below-ground productivity under drought conditions in grasslands of varying species richness. (abbrevia
Water scarcity is increasing in many regions of the world. There are three levels on which competition for water occurs: between countries, among different sectors within one country such as agriculture, industry and urban consumers and among different producers within one sector. Because of the common pool properties of water the degree of government intervention in this sector is strong and political lobbying is common. In this project a regionalized CGE (Computable General Equilibrium) shall be developed in which water is incorporated as an intermediate input differentiated according to water quality. This will allow to analyze the effects of various water price and policy scenarios from an efficiency as well as a distributive perspective.
Vegetation & Ecosystems: Within the vegetation research statistical and special hyperspectral analysis procedures are used to develop new methods to predict canopy biochemistry, such as nitrogen and carbon concentration or water content. Biochemical processes are all related to the foliar chemistry of vegetation and thus to the carbon and nitrogen cycles. Hence, biochemical information products contribute to many environmental applications. For instance ecosystem models can be parameterized with the generated products that can help to better understand CO2 fluxes and net primary production (NPP) in the framework of the Kyoto Protocol. Traditional measurement of forest canopy level biochemistry is time-consuming, expensive and spatially constrained. Remote sensing allows for repeatable and continuous prediction of biochemical information over a wide spatial scale and thus facilitates the understanding of ecosystem functions. For the retrieval of biochemistry products to be used for environmental applications, the transfer of the developed methods from airborne hyperspectral to spaceborne data is fundamental. This transfer involves spectral and spatial up-scaling. Additionally, spaceborne reflectance data contain angular effects due to the sensor field of view and observation geometry, which can finally influence biochemistry estimates. However, multi-angular reflectance data contain added information about vegetation structure. Since correct biochemistry mapping is linked to accurate vegetation structure, forest biochemistry products may be improved with multi-angular data. Our goals in the field of biochemistry prediction are to transfer the developed airborne-based methods to spaceborne data and to evaluate different methods for up-scaling. Water resources: The SNF project targets at the key aim of the joint EU, ESA GMES initiative to establish operational services for the assessment of water resources in terms of quality, quantity and usage. It has been defined as a major challenge in the scope of GMES activities and it is of crucial importance in most developing countries and at a global level (EC, 2005). RSL is developing new methodology (semi-empirical and analytical methods) for the retrieval of water constituents in order to establish scientific algorithm development activities with special emphasis on APEX retrieval algorithms for water constituent s retrieval and the discrimination of macro phytes and algae types. Thanks to the unique performance, the APEX instrument will facilitate the observation of regional scale features (e.g., Harmful Algae Blooms) and enable the study of complex waters with unprecedented accuracy. The development of remote sensing algorithms to retrieve phytoplankton species and physiology is a challenging endeavor of high importance to assess biological activities in the water and therefore water quality by better means. (abridged text)