In dem Flyer wir beschrieben, wie mit schwerkranken Füchsen in der Schonzeit, umgegangen werden muß.
GRACE gravity measurements provide a direct measure of water storage changes over continents. As such, it enables---for the first time---to close the continental water balance on large scales, and a direct determination of actual evapotranspiration---the unknown component of water balance---from terrestrial precipitation and run-off measurements on large scales. Atmospheric moisture flux offers another independent way of determining water storage changes, where there is no need for evapotranspiration information. This allows for a mutual inter-comparison of data from three independent disciplines and an evaluation of hydrological and atmospheric models. Thus the overall objectives of the project are 1. the direct analysis of large-scale water balances, and 2. the quantification of related uncertainties for large catchment areas in different climatic zones. In order to achieve consistent water balances, the mass change rates from GRACE, hydrology, and hydrometeorology have to be evaluated with respect to natural fluctuations and intrinsic errors. Statistical investigations are needed to characterize the respective contributions. Current results: Mass change estimates from GRACE are more accurate for large catchments (deeper 250,000 sq. km.) than for small catchments. 1. Vertically integrated moisture flux divergences from regional and global atmospheric models provide valuable constraints for estimating mass changes from GRACE. 2. A comparison of GRACE with hydrology datasets indicates that there is a sizeable amount of outliers in GRACE. These outliers have to be removed before any analysis can be done with the GRACE data. 3. Satellite RADAR altimetry provides estimates of runoff from catchments, where in situ measurements are not available, which helps in the validation and evaluation of GRACE derived mass change estimates.
GRACE gravity measurements provide a direct measure of water storage changes over continents. Thus, this novel technique enables for the first time to close the continental water balance on large scales. We propose to use GRACE gravimetry to directly determine large scale actual evapotranspiration from ground-based measurements of precipitation and discharge on large basins. The project will also provide a previously not available direct determination of atmospheric moisture fluxes on large basins from storage changes and discharge. As such, it enables a novel evaluation of atmospheric model data. However, the anisotropic error structure of conventional GRACE products is limiting their utility even for the largest basins available. Hydrological quasi-signals appear in areas, e.g. deserts, where no signal exists. To this end, we develop a new approach to GRACE error modelling, that makes use of known mass changes and their uncertainties, derived from hydrological constraints for selected areas, e.g. with negligible inputs (deserts) or with negligible evapotranspiration (snow/ice -, high altitude regions). This strategy allows for a correction of the gravity signal beyond the conventional de-aliasing procedures and thus an improvement of resolution in terms of space, time and mass. The close interdisciplinary collaboration will ensure the establishment of GRACE as a reliable hydrological sensor. Our investigations of the characteristics of both the large scale actual evapotranspiration and the atmospheric moisture flux enable us to predict discharge from ungauged basins and to evaluate the corresponding uncertainty by use of GRACE data. The global coverage of data from gauged and ungauged basins will hence lead to an improved determination of the global continental and the respective atmospheric water budget with a minimum of model assumptions.
ECODIS will develop sensor technologies for monitoring the physicochemical reactivity and biological impact of inorganic and organic pollutant species in aquatic systems. ECODIS will also apply these technologies to the study of the short and long term chemical and biological status of aquatic ecosystems following a pollution disaster. Exposure conditions experienced by organisms are defined by the temporal profiles of concentration and speciation of pollutants. These profiles will be quantitatively linked to biological effects via an innovative dynamic approach based on the flux of pollutant species as a key parameter in effective ecosystem quality. The dynamic features of pollutant species distributions over biotic and abiotic components will be a basic component of a new generic dynamic approach for any macroscopic aquatic ecosystem impacted by a pollution disaster event. This will involve the integration of the dynamic features of pollutants with their macroscale transport resulting from diffusion and flows in the water body. One of the major goals of ECODIS is to arrive at a model that includes predicted pollutant species distributions, and ensuing biological risks, in all compartments of the aquatic ecosystem as a function of time and space. Especially in disaster situations, the pollutant sink/source functioning of ecosystems under extreme load will be a key factor in the rate of spread of the disaster impact. ECODIS will couple the sink/source function with the transport modelling and derive the ensuing immediate and long term impact of a given pollution disaster. ECODIS will also open the way for developing sophisticated strategies for dynamic risk assessment and disaster management policies. One of the ultimate goals in ECODIS's action plan is the formulation of a set of guidelines for monitoring, data management, and interpretation of pollution disasters. Prime Contractor: Wageningen Universiteit; Wageningen; Netherland.
The international project 'Global Land Ice Measurements from Space' (GLIMS) establishes a complete remote sensing based inventory of the glaciers of the world. Glacial changes are indicators of changes in regional and global climate. GLIMS' mission to establish a global inventory of ice will provide the community with data for later comparison. Monitoring glaciers across the globe and understanding not only the cause of those changes, but the effects, will lead us to a greater understanding of global change and its causes. IPG Freiburg is the Regional Center for the Antarctic Peninsula within GLIMS.
Problem Statement: Davos, a research site Photo: W. Schönenberger (WSL) Simulations of the effects from changing environmental conditions on water cycles and hydrological processes often base on incomplete existing input- and model-parameters. In this context comprehensive sensitivity analyses are important, which allow to assess the influence of deviations and initial conditions on the results. Within the project, we investigate the spatial and temporal development of water cycles in the Swiss Alps for the next decades as influenced by climate change. In addition, we implement error propagation and sensitivity analysis of the models used, in particular the cross-scaling problems influencing the model resolution's accuracy and precision. We will use innovative methods to verify and assess Daymet for the complex terrain of Switzerland as well as to evaluate Biome-BGC for the simulations of ecosystem developments with respect to water cycles. Scenarios are afflicted with uncertainties; to quantify the dimension of these errors and to assess the quality of the deployed models for scenarios we implement a sensitivity analysis. Objectives: The main goal of this project is to assess the impact of climatic change on the water cycle in forest ecosystems as a function of abiotic site factors, by evaluating the reliability and plausibility of different approaches to model the hydrological cycle in space and time. This goal can be further divided into the following sub-goals: Objective A Developments and changes of the hydrological state will be estimated, depending on the forest ecosystem, the climate, and the topographical unique characteristics of the Swiss Alps. Objective B Quantification of implicit uncertainties by sensitivity analysis and error propagation in the simulation process. Objective C Assessment of uncertainties of digital data representation (e.g. digital terrain surface) by means of suitable mathematical methods in different scales (cross-scaling). Research Plan The Project will investigate the spatial and temporal development of forest ecosystems in the Swiss Alps as influenced by a changing climate during the next five decades. The following models and methods will be employed: Daymet to generate climatological surfaces; Biome-BGC a process model for terrestrial ecosystems; GLUE and GSA. The objective is not to develop new, or to enhance existing models but to evaluate the quality, the reliability and the uncertainties using error simulations and predictions. Following steps will be conducted: Validation of a verified and calibrated model: We will simulate the daily minimum and maximum temperatures and the daily total precipitation (snow and water separately) for the Swiss Alps from 1961 until 2000. Plausibility analysis of future water cylces: With the second step, etc.
In many eco-regions of the world, fires are a major driver of vegetation development. Global warming is likely to change fire frequency and intensity at the regional scale, thus causing vegetation shifts. In regions where forest fires so far have played only a minor role, they may become a key element determining vegetation composition, landscape dynamics and ecosystem functions. However, fire regimes, i.e., the spatial extent, intensity, and frequency of fires, are determined by many factors in addition to climate. Human activities, vegetation composition and structure, fuel load, and landscape patterns also have to be taken into consideration to determine fire risk. Understanding and disentangling the various factors that are crucial for shaping the current fire regime and for predicting the likely future fire regime thus requires a multi-faceted approach. In the proposed project, we intend to analyze the past, present, and future fire regimes of a region that is likely to become more fire-prone in the future, i.e., the Canton of Valais (Switzerland), a dry, interior valley of the European Alps. Specifically, we will assess the relative impacts of climate, vegetation properties and human activities on the fire regime. Project aims: To elucidate the historical (100 to 180 years) patterns of the fire regime in the Valais (Switzerland). To perform an in-depth analysis of the changes of the historical fire regime in space and time. To compare these results with the findings on the fire regime of a neighboring region, the Ticino (Switzerland). Whereas one thesis focuses on the historical aspects, an other thesis, located at the ETH aims at using these data to test and improve the LANDCLIM model with respect to (a) its accuracy for historical and current climate and land-use conditions of the Valais and (b) its ability to project future changes in the fire regime in the Valais and the European Alps in general.
Das Georadar ist ein geeignetes Verfahren zur Ortung von Lagerungsanomalien im Bodengefüge, die durch natürliche geologische Begebenheiten oder auch durch vom Menschen geschaffene Einflüsse entstehen können. Hierzu zählen alle baulichen Veränderungen im Boden. Von besonderem Interesse sind diese Anomalien dann, wenn es zu einer Gefährdung von Menschen oder Bauwerken kommen kann. Der Eintrag von Bodenmaterial in einen Abwasserkanal mit infiltrierendem Grundwasser kann das Bodengefüge soweit destabilisieren, dass es zum Einbruch der Oberfläche, einem sogenannten Tagbruch, kommen kann. Mit Hilfe des Georadars können Lagerungsanomalien detektiert werden, bevor es zu einer ernsthaften Schädigung des Straßenkörpers und weiterer Bauwerke kommt. In diesem hier vorgestellten Vorhaben wurde mit Hilfe eines Georadarsystems von der Straßenoberfläche aus der Untergrund bis zu einer Tiefe von ca. 5 m im Bereich erdverlegter Abwasserkanäle untersucht. Messungen in fünf Kommunen wurden ergänzt durch Messversuche auf einem Testfeld, in dem unter definierten Randbedingungen verschiedene Hohlräume und verschiedene Lagerungsdichten simuliert und erfasst wurden. Die Messmuster der Untersuchungen am Testfeld dienten zur Verifizierung der Messergebnisse in den Kommunen. Um die Einsatzmöglichkeit des Georadars für Kanalnetzbetreiber zu verbessern, wurde in diesem Vorhaben ein Datenmanagementsystem entwickelt, mit dessen Hilfe die Untersuchungen zwischen Auftraggeber und Auftragnehmer auszutauschen, zu bewerten und zu visualisieren sind. Aus bestehenden Standards wurde ein XML-basiertes Austauschformat entworfen, mit dem die Fachdaten plattformunabhängig und mit vertretbarem Aufwand in verschiedene Kanalinformationssysteme eingebunden werden können. Erweitert durch den verwendeten GML-Standard ist dies auch in Bezug auf die Visualisierungen möglich, die mit Hilfe der Geometriedaten generiert werden. Es werden hinsichtlich einer praxisgerechten Visualisierung die Messdaten georeferenziert, indem nicht nur die durch das Messfahrzeug aufgenommenen GPS-Koordinaten in verschiedene Koordinaten-Systeme transformiert wurden, sondern auch ein Datenmanagement entwickelt wurde, das es ermöglicht, die Lagegenauigkeit der erfassten GPS-Signale zu überprüfen und zu korrigieren. Anhand der referenzierten Daten wurden zwei Darstellungsformen entwickelt, die sich in bestehende Visualisierungen, wie sie bei Kanalinformationssystemen verwendet werden, integrieren. Diese Verschneidung ermöglicht den Kommunen, die Untersuchungen bei planerischen Sanierungsmaßnahmen zu berücksichtigen. Für Georadaruntersuchungen aus nichtbegehbaren Kanälen heraus wurde ein Kanalroboter als Labormuster durch die Firma Wiebe Gleisbaumschienen GmbH entwickelt.
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.
A concept that utilizes parameters retrieved from synthetic aperture radar (SAR) imagery will be devised in order to evaluate the atmospheric drag coefficient of sea ice. Methods will be developed for mapping and quantifying sea ice surface structure and deformation (e. g. floe size distribution, ridge spacing) from radar data. Considering that different SAR systems will be launched into space in the near future, the proposed investigations consider the effect of radar frequency, polarization, and spatial resolutions on the parameter retrieval. Retrieval methods and their accuracy will be assessed. Potential correlations between SAR backscatter variations, retrieved parameters related to sea ice deformation and surface structure, and the atmospheric drag coefficient will be analysed. The utilization of the retrieved parameters will be tested in numerical simulations of atmospheric boundary layer processes. Quantitative information about the sea ice surface structure and deformation is also of use for modelling sea ice dynamics, estimating sea ice mass balance, classifying ice types, and for safety and efficiency of marine transport and offshore operations.
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