API src

Found 329 results.

Sub project: Imaging Induced Seismicity at the KTB

Das Projekt "Sub project: Imaging Induced Seismicity at the KTB" wird vom Umweltbundesamt gefördert und von Universität Hamburg, Zentrum für Meeres- und Klimaforschung, Institut für Geophysik durchgeführt. The observation of naturally or artificially generated acoustic emissions (i.e., small earthquakes) by seismic networks is a powerful tool to image transport processes in the earth. During the injection experiments at the KTB a large number of events were observed. The precise spatio-temporal characterization of the seismic events is of utmost importance since all following interpretations (e.g., transport properties) rely entirely on this result. The localization of the events depends on the model used for the localization. The anisotropy of the KTB rocks is a well known feature but was not considered for the localization. Previous studies demonstrate that this leads to severe errors in the location of events. In this study we will first determine the anisotropic elastic features from the comprehensive KTB VSP data sets using 3-D anisotropic tomography for P- and S-waves. This step is essential for the localization. The obtained tomographic anisotropic 3-D model will then be used for the localization of the acoustic emissions of the 2000 and 2004 injection experiments. A newly developed technology based on reversed modelling or time reversed acoustic mirrors will be used to image the events. This techniques does not require picking of events and increases the detection level of the network owing to the stacking character of the method and allows to locate arrivals not visible in the individual seismograms of the network.

Sub project: Hydrochemical and hydraulic properties of the continental upper crust at the KTB site

Das Projekt "Sub project: Hydrochemical and hydraulic properties of the continental upper crust at the KTB site" wird vom Umweltbundesamt gefördert und von Regierungspräsidium Freiburg, Abteilung 9 - Landesamt für Geologie, Rohstoffe und Bergbau durchgeführt. A constant rate pumping test of one year duration is planed to be carried out in the 4.0 km deep pilot hole of KTB. Watertable fluctuations in the pilot borehole and in the 9.1 km deep main borehole will be monitored as well. A wealth of data (pumping rate, watertable/ pressure, temperature, salinity/electrical conductivity, water samples,....) will become available, some even online. The first objective of the proposed project is to determine the flow system (type of aquifer model). From this deduced hydraulic model follow the hydraulic characteristics (such as: transmissivity, storage coefficient, fracture lengt/ width/aperture, permeability of fractures and matrix,....) describing the properties of the crystalline basement rocks in vicinity of the KTB pilot- and main hole. The length of the expect test radius is some 1000 m. The proposed project intends also to determine the degree of the hydraulic connection between the two holes (having a depth difference of 5.1 km). Additional information, such as water analyses, will be needed in interpreting the hydraulic data. A second major objective is the modelling of water-rock interaction (WRI) processes using the chemical data of KTB fluids. In particular the time series of chemical data will be used to model the kinetic and time dependent processes. We expect as well to see some breakthroughs of 'fresh, clean' crystalline basement water and another breakthrough resulting from fluid stored in the main hole and its surrounding.

Sub project: Seismic site characterization in and around the COSC-1 drillhole

Das Projekt "Sub project: Seismic site characterization in and around the COSC-1 drillhole" wird vom Umweltbundesamt gefördert und von Technische Universität (TU) Bergakademie Freiberg, Institut für Geophysik und Geoinformatik durchgeführt. The project COSC (Collisional Orogeny in the Scandinavian Caledonides) focuses on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, both in the past and in recent active mountain belts (Gee et al., 2010). The Scandinavian Caledonides provide a well preserved example of Paleozoic plate collision, where the surface geology in combination with geophysical data provide control of the geometry of the Caledonian structure, both of the allochthon and the underlying autochthon, including a shallow W-dipping décollement surface on a thin skin of Cambrian black shales beneath the Caledonian thrust sheets. The structure of the basement underneath the décollement is highly reflective and apparently dominated by mafic sheets intruded into either late Paleoproterozoic granites or Mesoproterozoic volcanics and sandstones. The COSC project will examine the structure and physical conditions of these units, in particular the Caledonian nappes ('hot' allochthon) and the underlying basement, with two approximately 2.5 km deep drillholes, located near Åre and Mörsil in western Jämtland (http://www.sddp.se/COSC). In addition to that, the drillholes will provide unique information about the present temperature gradient in the Caledonides, the porosity and permeability of the rock formations, and the petrophysical properties of the rocks at depth. Existing regional seismic and magnetotelluric data have imaged the geometry of the upper crust, and pre-site seismic reflection survey were preformed in 2010 and 2011 to better define the exact drill site locations (Hedin et al., 2012). This present proposal is dedicated to complement these surface seismic measurements by drillhole-based investigations to better resolve and define the small-scale structures (including lithological boundaries, steeply dipping fault segments, fracture sets, etc.) around the drillhole COSC-1. This will be achieved by a combination of seismic transmission and reflection experiments using a 3C borehole geophone system and complemented by 3C geophones at the surface, where sources and surface receivers will be aligned at different azimuths and centred around the borehole location. The data processing will employ recently developed advanced imaging techniques and will focus on, amongst other things, the analysis of anisotropic effects caused by aligned fractures and faults and their relation to the stress regime. The results of our investigations will be high-resolution images of the fine-scale structure of faults and fractures around the borehole. This information is vital not only for a reliable spatial extrapolation of the structural and petrophysical properties observed in the borehole, but also for a thorough understanding of the tectonic and geodynamic setting, including, but not limited to, the past and present stress regime.

Space-time modelling of rainfall using Copulas - a quasi meta-gaussian approach

Das Projekt "Space-time modelling of rainfall using Copulas - a quasi meta-gaussian approach" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasser- und Umweltsystemmodellierung durchgeführt. Stochastic space time modelling of precipitation is a scientific challenge with great practical importance. There are two key challenges: Firstly, rainfall is highly variable in its spatial and temporal distribution. Secondly, within a rain-field there are locations where the rainfall intensity is zero (a property referred to as 'intermittence'). The practical importance lies in the fact that spatially distributed rainfall fields are of key importance for designers and planners for flood protection. Moreover, the field of weather forecasting is more and more interested in correct spatially-distributed rainfall fields to enhance weather forecasts. Currently, there are no methods available which take these two properties adequately into account. We are suggesting the development of a method that can describe the spatial and temporal variability of rain fields and correctly takes intermittence into account. The purpose of this proposal is to develop a novel methodology for multisite precipitation modelling which is based on Copulas. Copulas are the method of choice to describe spatial and temporal dependence structures, because Copulas allow to describe such a dependence in its purest form. This methodology should be applied to different climatic conditions in Germany and in South-Africa. Different climatic conditions imply a different spatial and temporal distribution of rainfall, and applying the proposed model there will be an ultimate test for the model. First step of the development is to create and test the model for the daily time scale using conventional observations. Subsequently, the model will be tested for smaller time steps, as small as one hour. The model should serve both as a precipitation generating procedure and as the basis for an interpolator and a conditional simulator. The research is planned to be conducted bilaterally in Germany and South Africa and is aimed to complement present research activities both on Copulas and precipitation modelling.

Sub project: What ends an Interglacial? Feedbacks between tropical rainfall, Atlantic climate and ice sheets during the Last Interglacial (EndLIG)

Das Projekt "Sub project: What ends an Interglacial? Feedbacks between tropical rainfall, Atlantic climate and ice sheets during the Last Interglacial (EndLIG)" wird vom Umweltbundesamt gefördert und von Universität Bremen, Fachbereich 5 Geowissenschaften, Fachgebiet Geosystem Modellierung durchgeführt. When and how the present interglacial will end remains an open question. With a relatively wellknown climate, the Last Interglacial (LIG) and following glacial inception can shed some light on the climate mechanisms leading to the establishment of a new ice age. Two key questions arise from the chain of climate events known to end the LIG: (1) Did the interglacial North Atlantic warmth, prolonged by an active thermohaline circulation (THC), favor or delay the growth of northern ice sheets? (2) Did reorganizations in South American moisture contribute to prolong the North Atlantic warmth by maintaining a salty North Atlantic and active THC at the end of the LIG, as suggested by tropical moisture feedbacks observed during glacial times? To address these questions, we propose here to combine new paleoclimate reconstructions with climate model experiments. First, we will reconstruct the detailed evolution of the South American rainbelt during the last glacial inception, by applying complementary proxies on a transect of marine sediment cores. Second, we will assess the impact of tropical hydrologic changes on tropical Atlantic sea surface salinities (SSS) and the Atlantic THC, by comparing tropical Atlantic SSS and deep-water properties with model sensitivity experiments where we will vary the tropical freshwater forcing. Finally, we will perform a transient climate/ice-sheet model run for the last glacial inception, and a sensitivity study, in which different ocean heat fluxes will be imposed to investigate the effect of prolonged North Atlantic warmth on ice sheet growth.

Tagung 'Welterbe und nachhaltige Entwicklung' an der INA Vilm

Das Projekt "Tagung 'Welterbe und nachhaltige Entwicklung' an der INA Vilm" wird vom Umweltbundesamt gefördert und von Bundesamt für Naturschutz durchgeführt. Vom 16. - 20. Oktober 2017 hat an der INA die Tagung 'World Heritage and Climate Change - Towards an Update of the Policy Document on the Impacts of Climate Change on World Heritage Properties' stattgefunden. Mitveranstalter waren IUCN, das UNESCO-Welterbezentrum, sowie die beiden anderen Beratungsorganisationen der Welterbekonvention, ICOMOS und ICCROM. Zielsetzung des Workshops war es, zur Umsetzung der Entscheidungen des Welterbekomitees von 2016 und 2017 beizutragen, welche eine Überarbeitung des 'Policy Documents on the Impacts of Climate Change on World Heritage Properties' fordert. In den Prozessen der Welterbekonvention wird das Thema 'Sustainable Development' mittelfristig eine wichtige Rolle spielen. Der Klimawandel ist ein zentrales Element der 'Policy for the Integration of a Sustainable Development Perspective into the Processes of the World Heritage Convention'. Damit stand der Workshop in direktem Zusammenhang mit dem bereits 2016 durchgeführten Workshop zum Thema 'World Heritage and Sustainable Development'. Die Veranstaltung war mit 20 internationalen Expertinnen und Experten aus 15 verschiedenen Ländern sehr gut besucht. Es ist gelungen Expertinnen und Experten aus allen globalen Regionen, dem Natur- und Kulturerbesektor, sowie Vertreter der Mitveranstalter zusammen zu bringen. Die Ergebnisse des Workshops lassen sich wie folgt zusammenfassen: - Die TeilnehmerInnen stellten fest, dass Klimawandel sich in den vergangenen Jahren zu einem der Haupteinflussfaktoren auf Welterbestätten entwickelt hat. - Die aktuelle Policy, 2007 verabschiedet, benötigt eine umfassende Überarbeitung, da sie sich ausschließlich mit dem Management von Klimawandelfolgen in Welterbstätten befasst und übergeordnete Fragen zum Zusammenhang zwischen Welterbe und Klimawandel und neue Entwicklungen im internationalen Klimaschutz nicht behandelt. - Im Workshop wurden Empfehlungen im Hinblick auf diese Überarbeitung entwickelt, die sich mit den Inhalten der zukünftigen 'Policy', dem Ansatz für die Umsetzung der neuen Policy und dem weiteren Prozess zur Erarbeitung dieser befassen. Die wichtigsten Ergebnisse des Workshops wurden in einem Bericht zusammengefasst und werden direkt in den weiteren Prozess zur Überarbeitung des Dokumentes einfließen, welcher vom UNESCO-Welterbezentrum und den Beratungsorganisationen gesteuert wird. Dieser Bericht wurde vom Welterbezentrum bereits auf dessen Webseite veröffentlicht.

INI 1128575 STP-2: Fate of Plant Residues in Soil Organic Matter Pools under Contrast Land Use as Evaluated by Two Tracer Techniques

Das Projekt "INI 1128575 STP-2: Fate of Plant Residues in Soil Organic Matter Pools under Contrast Land Use as Evaluated by Two Tracer Techniques" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Geowissenschaften, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Agrarökosystemforschung durchgeführt. Soil C sequestration through changes in land use and management is one of the important strategies to mitigate the global greenhouse effect. Plant residue is the primary source of C formation and sequestration in soil. The relative contribution of residues depends upon composition and decomposability of litter which is a function of lad use and management. The present project is conceived with objective to evaluate the fate of plant residue in soil C influenced by different land-use management practices. Ultimate aim to sketch policy for appropriate management practices, which would facilitate enrichment of C stock in soils for maintaining soil health and fertility as well as mitigation of global warming by C sequestration. Management practices like intensity of tilling and no tillage have a definite effect on SOC stock; it would be considered as pertinent management practice for residue derived C-turnover. To fulfil the objective as stated, representative soil samples will be collected under various land covers/uses and management practices and analysed for important physico chemical properties e.g. pH, CEC, clay content, bulk density, soil water storage, and soil porosity are the important soil physical parameters which influences C load in soil. Different pools of C viz. total SOC (Ctot), Water stable aggregates, labile fractions of oxidisable organic carbon etc. will be studied to know the C stock and its distribution in soil. Impact of added plant residue on C sequestration and C dynamics of plant residues decomposition in contrast land use will be analyzed and quantified by using 14C labelled plant residues as well as 13C natural abundance and allow for differentiation between residues-derived carbon and native SOC. Labeled microbial biomass C and mineralizable C, acetone exactable reside, 14C and d13C in CO2 and in SOM pool will be measured that may provide precise estimates of residues decomposition rates and contribution in soil organic C. Microbial biomass carbon (Cmic) and mineralizable carbon (Cmin) measured as early indicators of future trends in total SOM as it provides a good measure of labile organic matter because it directly reflects recent soil organic matter turnover. Data on biomass productivity will also be collected from those sites. Results would help us to know the relative efficiency of different land use managements for organic C enrichment or depletion in soils.

B 4.1: Land vulnerability and land suitability analysis in Northern Vietnam

Das Projekt "B 4.1: Land vulnerability and land suitability analysis in Northern Vietnam" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Bodenkunde und Standortslehre durchgeführt. As populations are steadily increasing in VN, farming land becomes scarce and new areas are opened up for cultivation, mainly in mountainous regions. On the fragile steep slopes deforestation and soil erosion are the well-known consequences. Land use in Yen Chau District, the study area in Son La, has significantly changed in the last decades. Until now, mainly soil degradation is reported on upland fields, but also soil erosion is increasing, both decreasing crop yields. In this project a database for topography, land use and soil properties within two subcatchments in Yen Chau will be created. The main goal of the project will be to carry out land suitability analysis and land vulnerability analysis, based on the data stored in the database, to provide tools for future sustainable land use planning. For this, a broad approach is intended by assessing land suitability for various crops, fruit trees and livestock production as well as to work out land vulnerability of the research area based on soil characteristics and topographic situation. The land suitability and vulnerability analysis will be carried out with the adopted SOTER (Soil and Terrain) approach. Normally used for a 1:500000 scale the SOTER technology will be developed for a 1:50.000 scale for two subcatchments. This is especially necessary because the closely cooperating projects C4.1 (Land use modelling), B5.1 (Water quality analysis) and G1.2 (Sustainability strategies) will rely on the spatial data of this scale. A totally new objective will be attempted by breaking down the SOTER technology to a scale of 1:5.000 for a village area in one of the selected subcatchments to regard the typical small-scale land use mosaic of a village area. Only with this scale the typical small scale land use mosaic of a village area can relatively precisely be mapped taking settlement areas, fish ponds, homegardens, fields, pastures, forests and scrubland as well as streams and creeks into account. With this approach it will be the first time possible to evaluate agricultural production on a village level using the SOTER technology. The SOTER database will be used with algorithms and soil transfer functions in order to derive soil suitability and soil vulnerability of certain areas. For the suitability analysis of different crops mainly the static approach for water regime, nutrient regime and potential root zone will be generated. As an important tool for decision making the erosion hazards due to water and especially gravity has to be visualized. As participatory soil mapping provides valuable additional information for land use evaluation and potential planning, this approach will be integrated on both the subcatchment and the village level in joint cooperation with A1.3 (Participatory Research). Finally, land use scenarios regarding different factors, e.g. change of cropping patterns, introduction of fruit trees, intensification of fish production or changes in market access, will be modelled.

The role of turgor in rain-cracking of sweet cherry fruit

Das Projekt "The role of turgor in rain-cracking of sweet cherry fruit" wird vom Umweltbundesamt gefördert und von Leibniz Universität Hannover, Institut für Biologische Produktionssysteme, Fachgebiet Obstbau durchgeführt. Rain-cracking limits the production of many soft and fleshy fruit including sweet cherries world wide. Cracking is thought to result from increased water uptake through surface and pedicel. Water uptake increases fruit volume, and hence, turgor of cells (Pcell) and the pressure inside the fruit (Pfruit) and subjects the skin to tangential stress and hence, strain. When the strain exceeds the limits of extensibility the fruit cracks. This hypothesis is referred to as the Pfruit driven strain cracking. Based on this hypothesis cracking is related to two independent groups of factors: (1) water transport characteristics and (2) the intrinsic cracking susceptibility of the fruit defined as the amount of cracking per unit water uptake. The intrinsic cracking susceptibility thus reflects the mechanical constitution of the fruit. Most studies focussed on water transport through the fruit surface (factors 1), but only little information is available on the mechanical constitution (i.e., Pfruit and Pcell, tensile properties such as fracture strain, fracture pressure and modulus of elasticity of the exocarp; factors 2). The few published estimates of Pfruit in sweet cherry are all obtained indirectly (calculated from fruit water potential and osmotic potentials of juice extracts) and unrealistically high. They exceed those measured by pressure probe techniques in mature grape berry by several orders of magnitude. The objective of the proposed project is to test the hypothesis of the Pfruit driven strain cracking. Initially we will focus on establishing systems of widely differing intrinsic cracking susceptibility by varying species (sweet and sour cherry, Ribes and Vaccinium berries, plum, tomato), genotype (within sweet cherry), stage of development and temperature. These systems will then be used for testing the hypothesis of Pfruit driven strain cracking. We will quantify Pfruit und Pcell by pressure probe techniques and compression tests and the mechanical properties of the exocarp using biaxial tensile tests. When the presence of high Pfruit and Pcell is confirmed by direct measurements, subsequent studies will focus on the mode of failure of the exocarp (fracture along vs. across cell walls) and the relationship between failure thresholds and morphometric characteristics of the exocarp. However, when Pfruit und Pcell are low, the hypothesis of Pfruit driven strain cracking must be rejected and the mechanistic basis for low pressures (presence of apoplastic solutes) clarified on a temporal (in the course of development) and a spatial scale (exocarp vs. mesocarp). We focus on sweet cherry, because detailed information on this species and experience in extending the short harvest period is available. Where appropriate, other cracking susceptible species (sour cherry, plum, Vaccinium, Ribes, tomato) will be included to further extend the experimental period and to maximize the range in intrinsic cracking susceptibility.

Sub project: On the geochemistry of crustal fluids and gases of the San Andreas Fault Zone - Real-time mud gas monitoring during ICDP-SAFOD drilling

Das Projekt "Sub project: On the geochemistry of crustal fluids and gases of the San Andreas Fault Zone - Real-time mud gas monitoring during ICDP-SAFOD drilling" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. Within this project gases of crustal origin will be investigated on their depth distribution as well as elemental and isotopic compositions in order to determine the origin, genesis, development and ages of crustal gases and fluids in the active San Andreas fault zone. To achieve this goal in part, the drill mud composition and gas content should be monitored in real-time while drilling of the SAFOD main hole of the International Contoinental Drilling Programm (ICDP). Collected gas and fluid samples will be analyzed namely for stable and noble isotope composition. The aim of the project is to understand the geochemical behavior of fluids and gases depending on rock/water interaction, possible influences from the earth mantle (noble gas isotopes), transportation properties in fault systems, and their role in the earthquake cycle.

1 2 3 4 531 32 33