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Unterirdische Einzugsgebiete im Grundwasser

Die Daten sind aus dem Projekt „Bilanzierung des Grundwasserdargebotes für das Land Brandenburg“ (HGN-Gutachten 2021) im Zusammenhang mit den Daten zum Projekt „Hydroisohypsenplan 2017“ aus dem Umweltplan-Gutachten (2017) aggregiert worden. Auf Grundlage stichtagsbezogener Grundwasser-/ Oberflächenwasserstandsdaten des Frühjahres 2015 erfolgte über das Interpolationsverfahren „Detrended Kriging/Residual Kriging“ in Kombination mit einer geohydraulischen Modellierung, die Berechnung der Hydroisohypsen (Linien gleicher Grundwasserstände auf NHN bezogen). Für die Darstellung der unterirdischen Einzugsgebiete wurden zuerst die oberirdischen Einzugsgebiete ausgegrenzt. Danach erfolgte die Ausgrenzung der unterirdischen Einzugsgebiete in Ableitung der o. g. Hydrodynamik aus dem Frühjahr 2015. Unterirdische Einzugsgebiete werden auch Grundwassereinzugsgebiete genannt. Die Daten sind aus dem Projekt „Bilanzierung des Grundwasserdargebotes für das Land Brandenburg“ (HGN-Gutachten 2021) im Zusammenhang mit den Daten zum Projekt „Hydroisohypsenplan 2017“ aus dem Umweltplan-Gutachten (2017) aggregiert worden. Auf Grundlage stichtagsbezogener Grundwasser-/ Oberflächenwasserstandsdaten des Frühjahres 2015 erfolgte über das Interpolationsverfahren „Detrended Kriging/Residual Kriging“ in Kombination mit einer geohydraulischen Modellierung, die Berechnung der Hydroisohypsen (Linien gleicher Grundwasserstände auf NHN bezogen). Für die Darstellung der unterirdischen Einzugsgebiete wurden zuerst die oberirdischen Einzugsgebiete ausgegrenzt. Danach erfolgte die Ausgrenzung der unterirdischen Einzugsgebiete in Ableitung der o. g. Hydrodynamik aus dem Frühjahr 2015. Unterirdische Einzugsgebiete werden auch Grundwassereinzugsgebiete genannt.

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AURORa - Investigation of the Radar Backscatter of Rain Impinging on the Ocean Surface

Das Projekt "AURORa - Investigation of the Radar Backscatter of Rain Impinging on the Ocean Surface" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Meereskunde (IfM) durchgeführt. Over land, observations of rain rates are more or less operational. To obtain information about precipitation at the coastal zones, weather radars are used. However, over the oceans, especially away from the main shipping routes, no direct precipitation measurements are performed. In these regions, satellite data can provide information about precipitation events. Satellites deploying passive and active microwave sensors can operate independently of cloud cover and time of day. Passive microwave sensors give crude estimates of rain rates over large areas but cannot resolve small-scale rain events of short duration as are often observed in the tropics, for example. Active microwave sensors with high resolutions, such as synthetic aperture radars can provide more reliable information. Though the effect of rain on the atmosphere is a very topical area of research, the radar backscattering mechanisms at the water surface during rain events combined with wind are still not well understood. The purpose of this project is to investigate the radar backscattering from the water surface in the presence of rain and wind in order to interpret satellite radar data produced by active microwave sensors. Furthermore, the results should be embedded into models of the radar backscattering from the water surface to allow for estimating rain rates by using satellite data. Research topics: Rain impinging on a water surfaces generates splash products including crowns, cavities, stalks and secondary drops, which do not propagate, and ring waves and subsurface turbulence. We are investigating this phenomena at the wind-wave tank of the University of Hamburg. The tank is fitted with an artificial rain simulator of 2.3 m2 area mounted 4.5 m over the water surface. Rain drops of 2.1 and 2.9 mm in diameter with rain rates up to 100 mm/h have been produced. Wind with speeds 10 m/s and monomolecular slicks act on the water surface. The influence of the rain on the water surface is measured with a resistance type wire gauge, a two dimensional laser slope gauge and an coherent 9.8 GHz (x band) continuous wave scatterometer operating at VV-, HH- and HV-polarization. The influence of rain below the water surface is measured with colored raindrops which are observed with a video camera to investigate the turbulent motion and the depth of the mixed layer. At the North Sea Port of Buesum in Germany, a scatterometer operating at all polarizations and five frequencies will be mounted during summer of this year. The radar backscatter of the sea surface during rain events will be measured in combination with meteorological observations. With help of these measurements, existing radar backscatter models of the water surface will be improved for the presence of rain events. To validate the improved models, ERS-2 SAR-images will be compared with weather radar data.

14C content of specific organic compounds in subsoils

Das Projekt "14C content of specific organic compounds in subsoils" wird vom Umweltbundesamt gefördert und von Universität zu Köln, Institut für Geologie und Mineralogie durchgeführt. Organic matter (OM) composition and dynamic in subsoils is thought to be significantly different from those in surface soils. This has been suggested by increasing apparent 14C ages of bulk soil OM with depth suggesting that the amount of fresh, more easily degradable components is declining. Compositional changes have been inferred from declining ä13C values and C/N ratios indicative for stronger OM transformation. Beside these bulk OM data more specific results on OM composition and preservation mechanisms are very limited but modelling studies and results from incubation experiments suggest the presence and mineralization of younger, 'reactive carbon pool in subsoils. Less refractory OM components may be protected against degradation by interaction with soil mineral particles and within aggregates as suggested by the very limited number of more specific OM analysis e.g., identification of organic compound in soil fractions. The objective of this project is to characterize the composition, transformation, stabilization and bioavailability of OM in subsurface horizons on the molecular level: 1) major sources and compositional changes with depth will be identified by analysis of different lipid compound classes in surface and subsoil horizons, 2) the origin and stabilization of 'reactive OM will be revealed by lipid distributions and 14C values of soil fractions and of selected plant-specific lipids, and 3) organic substrates metabolized by microbial communities in subsoils are identified by distributional and 14C analysis of microbial membrane lipids. Besides detailed analyses of three soil profiles at the subsoil observatory site (Grinderwald), information on regional variability will be gained from analyses of soil profiles at sites with different parent material.

From subsurface structures to functions and texture - linking virtual realities and experiments at the plot and hillslope scales

Das Projekt "From subsurface structures to functions and texture - linking virtual realities and experiments at the plot and hillslope scales" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Institut für Wasser und Gewässerentwicklung, Bereich Hydrologie durchgeführt. This project will explore the interplay between soil water, tracer and soil heat budgets depending on the prevailing context and develop advanced approaches for their coupled treatment within the subsurface domains of an EFU (the least entity of the CAOS model). Based on an improved understanding of the fingerprints of vertical preferential flow in the water, mass and heat transport in the unsaturated zone we will derive suitable closure relations that account for these fingerprints in the unsaturated subsurface domain of an EFU during rainfall driven conditions. We will furthermore derive descriptions for water, mass and heat budgets in the unsaturated subsurface domain during energy driven conditions and derive the necessary constitutive relations that account for the effect of soil heterogeneity on storage of water, mass and energy based on virtual experiments. Next we will explore coupled water and heat transport in the saturated subsurface domain with special emphasis on groundwater surface water exchange and derive process descriptions of minimum adequate complexity. Furthermore we will contribute to an optimal combination of soil physical and geophysical methods for exploring near subsurface lateral structures at the hillslope scale in joined work task with Project F.

Integrated water resources modeling and its uncertainty analysis for coastal watersheds under climate and land-use change

Das Projekt "Integrated water resources modeling and its uncertainty analysis for coastal watersheds under climate and land-use change" wird vom Umweltbundesamt gefördert und von Forschungszentrum Jülich GmbH, Institut für Bio-und Geowissenschaften (IBG), IBG-3 Agrosphäre durchgeführt. It has been shown that three-dimensional groundwater dynamics may have strong influence on the mass-and energy balance (MEB) of the landsurface. On the other hand, the landsurface MEB, including processes such as evapotranspiration, plays a key role in groundwater recharge. Therefore, changes in land-use type and patterns may have significant influence on the MEB and groundwater recharge in the future, because evapotranspiration is strongly determined by the vegetation cover. This illustrates the reciprocity in the coupled hydrologic and energy cycles. Without explicit inclusion of groundwater dynamics, MEB calculations are burdened with significant inaccuracies and uncertainties (and vice versa), and may lead to wrong predictions. The goal is to study and quantify the influence of groundwater dynamics on the MEB of the landsurface over large spatial and temporal scales and to derive estimates of groundwater recharge and evapotranspiration influenced by future climate and land-use change. The proposed study will work under the scientific exemplar that the subsurface-landsurface system must be represented in a physically consistent and integrated fashion. This will be achieved by a fusion of theoretical approaches and measured data. An existing integrated, high-performance computing simulation platform for MEB calculations of the subsurface-landsurface system will be improved and applied to the large scale Luanhe watershed in China for validation and prognostic purposes. For the first time, the entire system from the water table across the landsurface will be considered, which will lead to more accurate predictions of the system state. The MEB at the landsurface is governed by complex processes including plant transpiration. Until now, these processes are approximated via ad-hoc empirical approaches that have not been validated adequately using measurements. In this study, a more complete transpiration and root water uptake model will be implemented to account for e.g., variable root density distributions depending on subsurface moisture conditions that are commonly neglected and optimized stomatal resistance parameterizations. These approaches will enter directly into the integrated simulation platform. In a validation exercise, the simulation platform will be applied to the Luanhe watershed. Groundwater recharge - a parameter of major interest in the study region - will be extracted and the influence of climate and land-use change will be investigated. This will include scenario simulations of future climate and landuse changes in the region. As a demonstration, high-resolution, long-term forecasts of the MEB of the Luanhe catchment will be generated. These results will provide the foundation for management and mitigation strategies of potential consequences of climate and land-use change, which is the primary subject of the Chinese research team.

Understanding river-sediment-soil-groundwater interactions for support of management of waterbodies (river basin catchment areas) - AQUATERRA

Das Projekt "Understanding river-sediment-soil-groundwater interactions for support of management of waterbodies (river basin catchment areas) - AQUATERRA" wird vom Umweltbundesamt gefördert und von Attempto Service GmbH durchgeführt. Changes in climatic conditions, land use practices and soil and sediment pollution have large scale adverse impacts on water quantity and quality. The current knowledge base in river basin management is not adequate to deal with these impacts. AquaTerra is both integrating and developing knowledge to resolve this and disseminating it to stakeholders. In the water cycle, soil is a key element affecting groundwater recharge and the chemical composition of both subsurface and surface waters (the latter is additionally affected by sediments). The proper functioning of the river-sediment-soilgroundwater system is linked to key biogeochemical processes determining the filter, buffer and transformation capacity of soils and sediments. AquaTerra aims at a better understanding of the system as a whole by identifying relevant processes, quantifying the associated parameters and developing numerical models of the groundwater-soil-sediment-river system to identify adverse trends in soil functioning, water quantity and quality. The modelling addresses all relevant scales starting from micro-scale water/solid interactions, the transport of dissolved species, pollutants as well as suspended matter in soil and groundwater systems at the catchment scale, and finally the regional scale, with case studies located in major river basins in Europe. With this integrated modelling system, AquaTerra provides the basis for improved river basin management, enhanced soil and groundwater monitoring programs and the early identification and forecasting of impacts on water quantity and quality during this century. AquaTerra is committed to the dissemination and exploitation of project results through structured workshops, dedicated short courses, and the active participation of consortium partners in national and international conferences. The quality and direction of the project is supervised by a peer review panel.

Biogenic soil structures: feedbacks between bioactivity and spatial heterogeneity of water storage and fluxes from plot to hillslope scale

Das Projekt "Biogenic soil structures: feedbacks between bioactivity and spatial heterogeneity of water storage and fluxes from plot to hillslope scale" wird vom Umweltbundesamt gefördert und von Technische Universität Braunschweig, Institut für Geoökologie, Abteilung Umweltsystemanalyse durchgeführt. Soil structure determines a large part of the spatial heterogeneity in water storage and fluxes from the plot to the hillslope scale. In recent decades important progress in hydrological research has been achieved by including soil structure in hydrological models. One of the main problems herein remains the difficulty of measuring soil structure and quantifying its influence on hydrological processes. As soil structure is very often of biogenic origin (macropores), the main objective of this project is to use the influence of bioactivity and resulting soil structures to describe and support modelling of hydrological processes at different scales. Therefore, local scale bioactivity will be linked to local infiltration patterns under varying catchment conditions. At hillslope scale, the spatial distribution of bioactivity patterns will be linked to connectivity of subsurface structures to explain subsurface stormflow generation. Then we will apply species distribution modelling of key organisms in order to extrapolate the gained knowledge to the catchment scale. As on one hand, bioactivity influences the hydrological processes, but on the other hand the species distribution also depends on soil moisture contents, including the feedbacks between bioactivity and soil hydrology is pivotal for getting reliable predictions of catchment scale hydrological behavior under land use change and climate change.

Räumliche und zeitliche Änderung der Temperatur während eines Gashydrat-Produktionstests (Mallik 2002)

Das Projekt "Räumliche und zeitliche Änderung der Temperatur während eines Gashydrat-Produktionstests (Mallik 2002)" wird vom Umweltbundesamt gefördert und von GeoForschungsZentrum Potsdam (GFZ), Sektion 5.2 Geothermie durchgeführt. Sowohl das Ausmaß und die Verbreitung natürlicher Methanhydratvorkommen, als auch die Freisetzung von gasförmigem Methan beim Zerfall der Methanhydrate, werden maßgeblich von den unterirdischen Druck- und Temperaturbedingungen bestimmt. Bislang sind thermische Daten von Gashydratvorkommen jedoch nur in sehr geringen Umfang vorhanden. Im Rahmen des Mallik 2002 Forschungsbohrprogramms wurden drei 1200 m tiefe Bohrungen, die ein kontinentales Gashydratvorkommen unter Permafrost durchteufen, erfolgreich mit faseroptischen Messkabeln zur ortsverteilten Temperaturmessung ausgestattet. Über einen Zeitraum von 21 Monaten nach der Fertigstellung der Bohrungen wurden Temperaturmessungen durchgeführt. Erstmals wurden die Auswirkungen von Phasenübergängen innerhalb eines natürlichen Gashydratvorkommens in situ beobachtet. Anhand der beobachteten Anomalien des Temperaturgradienten wurden die Tiefenlagen der Basis der Gashydratvorkommen und des Permafrosts jeweils bei rund 1103-1104 plus/minus 3.5 m, bzw. 599-604 plus/minus 3.5 m unterhalb der Geländeoberkante bestimmt. Die gemeinsame Interpretation der geothermischen Daten mit den geophysikalischen Bohrlochmessdaten weist darauf hin, dass Veränderungen der Wärmeleitfähigkeit im Wesentlichen durch lithologische Wechsel verursacht werden. Der Einfluss der Hydratsättigung ist nur von untergeordneter Bedeutung für die effektive Wärmeleitfähigkeit des Gesteins. Das durchgeführte Online-Temperaturmonitoring lieferte die entscheidenden Informationen während der Durchführung des fünftägigen thermischen Stimulationsexperiments. Die Messergebnisse wurden zur Kalibrierung und Validierung numerischer Reservoirsimulatoren zur Berechnung gekoppelter thermo-hydraulischer Prozesse bei der Zersetzung von Gashydrat eingesetzt.

Glazial/interglaziale Variabilität der Wassermassenstruktur und der biologischen Produktion im pazifischen Sektor des Südozeans, Erfassung von Mechanismen mit Einfluss auf den Atmosphären-Ozean CO2-Gasaustausch, Synthese von Klima- und biogeochemischer Modellierung mit Paläoproxy-Rekonstruktionen

Das Projekt "Glazial/interglaziale Variabilität der Wassermassenstruktur und der biologischen Produktion im pazifischen Sektor des Südozeans, Erfassung von Mechanismen mit Einfluss auf den Atmosphären-Ozean CO2-Gasaustausch, Synthese von Klima- und biogeochemischer Modellierung mit Paläoproxy-Rekonstruktionen" wird vom Umweltbundesamt gefördert und von Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung durchgeführt. Atmospheric CO2 concentrations present a repetitive pattern of gradual decline and rapid increase during the last climate cycles, closely related to temperature and sea level change. During the Last Glacial Maximum (LGM; 23-19 kyr BP), when sea level was ca. 120 m below present, the ocean must have stored additionally about 750 Gt carbon. There is consensus that the Southern Ocean represents a key area governing past and present CO2 change. The latter is not only of high scientific but also of socio-economic and political concern since the Southern Ocean provides the potential for an efficient sink of anthropogenic carbon. However, the sensitivity of this carbon sink to climate-change induced reorganizations in wind patterns, ocean circulation, stratification, sea ice extent and biological production remains under debate. Models were not yet able to reproduce the necessary mechanisms involved, potentially due to a lack of the dynamic representation/resolution of atmospheric and oceanic circulation as well as missing carbon cycling. Data on past Southern Ocean hydrography and productivity are mainly from the Atlantic sector, thus do not adequately document conditions in the Pacific sector. This sector is not only the largest part of the Southern Ocean, but it also represents the main drainage area of the marine-based West Antarctic Ice Sheet (WAIS). In the proposed study we aim to generate paleo-data sets with a newly established proxy method from sediment core transects across the Pacific Southern Ocean. This will enhance the baselines for the understanding and modeling of the Southern Ocean's role in carbon cyling, i.e. ocean/atmosphere CO2 exchange and carbon sequestration. It will also allow insight into the response of the WAIS to past warmer than present conditions. Paired isotope measurements (oxygen, silicon) will be made on purified diatoms and radiolarians to describe glacial/interglacial contrasts in physical and nutrient properties at surface and subsurface water depth. This will be used to test (i) the impact of yet unconsidered dust-borne micronutrient deposition on the glacial South Pacific on shifts of primary productivity, Si-uptake rates and carbon export, (ii) the 'silicic-acid leakage' hypothesis (SALH) and (iii) the formation and extent of surface water stratification. Diatom and radiolarian oxygen isotopes will provide information on the timing of surface ocean salinity anomalies resulting from WAIS melt water. Climate model simulations using a complex coupled atmosphere ocean general circulation model (AOGCM) in combination with a sophisticated ocean biogeochemical model including Si-isotopes will be used for comparison with the paleo records. The analysis will cover spatial as well as temporal variability patterns of Southern Ocean hydrography, nutrient cycling and air-sea CO2-exchange. With the help of the climate model we aim to better separate and statistically analyse the individual impacts of ocean circulation and bio

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