Das Projekt "Biologische Vielfalt und menschlicher Einfluss in flachen Seen" wird vom Umweltbundesamt gefördert und von Universität Frankfurt, Zoologisches Institut durchgeführt. Objective/Problems to be solved: If sustainable management and restoration of biodiversity is to be successful, it is important to have cost-effective methods for reliable large-scale monitoring of biodiversity, to be able to assess the current state of biodiversity, determine trends and patterns and to evaluate the effectiveness of restoration measures. In addition, there is an urgent need for tools to predict the effects of human activity and restoration measures on the biodiversity of target ecosystems. The proposed project aims at providing the necessary methodologies and tools (indices, indicator species lists, predictive mathematical models) for monitoring biodiversity and assessing human impact on biodiversity in a specific type of habitat that is important in many areas of Europe: mesotrophic to eutrophic shallow lakes that are subject to natural or cultural eutrophication. Shallow lakes are abundant in Europe, are ecologically and economically very important, and are subject to many threats. Scientific objectives and approach: The objectives of BIOMAN are (1) to develop reliable and cost-effective indices for measuring overall biodiversity in the water column of shallow water bodies; (2) to develop mathematical tools that allow prediction of the effects of human impact on biodiversity in shallow waters, including the prediction of the response to restoration measures; (3) to compile a database on the current state of biodiversity in a representative sample of European shallow bodies, covering the classical food web (fish, zooplankton, phytoplankton) as well as the microbial loop (bacterioplankton and heterotrophic protists), and also covering genetic diversity of zooplankton and diversity as measured through the egg bank; and (4) to develop a reliable method to evaluate the success of restoration measures. In a large-scale field survey covering 96 shallow standing waters along a north-south gradient in Europe, we focus on organisms occurring in the water column, belonging to the microbial loop (bacteria, heterotrophic nanoflagellates, ciliates) and the classical food web (phytoplankton, zooplankton, fish). The ponds and lakes studied differ widely in the degree of human impact (relatively pristine and successfully restored habitats versus heavily impacted ones), degree of isolation, structural diversity, nutrient loading and size. We compare different measures of biodiversity in terms of the indices used (e.g. Hill numbers), the functional resolution (trophic level), the type of biodiversity measured (taxon diversity, genetic diversity within taxa) and the approach used for taxon delimitation (morphological or genetic criteria)... Prime Contractor: Katholieke Universiteit Leuven, Departement Biologie, Faculteit Wetenschappen, Laboratory of Aquatic Ecology; Leuven/Belgium.
Das Projekt "Salpetrige Saeure und ihr Einfluss auf die Oxidationsfaehigkeit der Atmosphaere" wird vom Umweltbundesamt gefördert und von Universität-Gesamthochschule Wuppertal, Fachbereich 9 Naturwissenschaften II, Physikalische Chemie durchgeführt. Objective/Problems to be solved: It is presently accepted that nitrous acid (HONO) plays an important role for the oxidation capacity of the atmosphere. In addition, HONO is an important indoor pollutant, which can react with amines leading to carcinogenic nitrosamines. However, many questions concerning the formation and degradation of this trace gas in the atmosphere are still poorly understood. Problems to be solved: by the consortium address the following questions: 1. What are the weights of the various HONO formation pathways in urban, rural and polar regions of the troposphere? 2. In particular, is the aerosol surface (soot, secondary organic, aqueous aerosol, cloud droplets) an important HONO source or is HONO formed only on the ground? 3. What is the quantitative relevance of HONO photolysis to the OH budget and consequently to the oxidation capacity of the atmosphere? Scientific objectives and approach: Significant progress towards answering these questions can only result from an integrated research project which combines field, laboratory and modelling studies. The field studies primarily focus on the formation of HONO in urban areas and take into account transport phenomena. HONO daytime formation rates are determined to clarify the importance of HONO photolysis to the oxidation capacity of the atmosphere not only at sunrise but also at noon. In addition, the vertical gradient of HONO is measured to differentiate between HONO formation on aerosols and on the ground. Finally, HONO is also measured in polar regions to provide a database which can be used to validate the assumption that the oxidation capacity in the polar region is controlled by HONO photolysis. In the laboratory studies kinetic and mechanistic investigations of the relevant heterogeneous reactions leading to conversion of nitrogen compounds, such as NOx, into HONO are performed. The study focus on HONO formation and loss processes on soot, secondary organic aerosol and aqueous surfaces. It is assumed that oxidisable surface groups can lead to rapid HONO formation. Organic aerosol particles, which constitute a major fraction of the atmospheric aerosol are believed to contain such oxidisable surface groups and hence may be a significant source of HONO in the atmosphere. Consequently, a key objective is to provide laboratory data needed to evaluate the significance of the organic aerosol as a source of atmospheric HONO. In the model studies tropospheric HONO formation is simulated by box and 3D calculations and compared to the field measurements. The model includes the present state of knowledge of HONO formation on different surfaces and is closely linked to the laboratory studies. A sensitivity analysis is performed to quantify the effect of uncertainties in the rates of the various HONO formation processes upon the concentrations of HONO, ozone and other important pollutants...
Das Projekt "Messungen von Ozon, Wasserdampf, Kohlenmonoxid und Stickoxiden durch Airbus-Flugzeuge im Dienst (MOZAIC-III) - O3- und H2O-Haushalt in der oberen Troposphaere/unteren Stratosphaere" wird vom Umweltbundesamt gefördert und von Forschungszentrum Jülich GmbH, Institut für Chemie und Dynamik der Geosphäre durchgeführt. Objective/Problems to be solved: The project proposes actions to detect, understand, assess and predict global change processes and to contribute to the European component of the global observing systems. It answers to interrogations of the origin, budget and evolution in the upper troposphere and lower stratosphere (UT/LS) of chemical species (ozone, water vapour) which have impact on air quality and climate, with special attention to the impact of aircraft emissions. Scientific objectives and approach: The MOZAIC-III project is designed for the evaluation of ozone and water vapour budgets in the tropopause region. It takes full advantage of the measuring capabilities of the in-service aircraft already equipped and of the database (O3, H2O) built up since August 1994. The purpose is to improve the current understanding on the processes active in this region of the atmosphere (UT/LS), and particularly on the aircraft impact. MOZAIC-III corresponds to installation, on the aircraft measuring units, of new CO and NOy devices and to the extension of the existing database of O3 and H2O measurements below 12 km altitude with simultaneous measurements of CO and NOy, in order to better characterise the origin of the air parcels sampled and the combined effects of transport and chemistry. The database is opened to the European research community. Data are analysed using statistical correlation, modelling of chemistry and dynamics, satellite data (ENVISAT, METEOSAT, TOVS) and assimilation methods. The duration of the series over almost 9 years allows to analyse trends, interannual variability, and correlations between species. The numerous data collected at a quasi global scale are used to improve current understanding of tropospheric chemical and dynamical processes and to quantify the ozone budget in the UT/LS region: stratospheric contribution, transport of pollution from PBL, free tropospheric formation, productions from NOx emitted by aircraft and NOx induced by lightning, surface deposition, chemical losses. The relation between upper tropospheric water vapour and sea surface temperature over tropical, sub-tropical and mid-latitude regions is investigated. Expected impacts: From the whole set of data collected since 1994, it is expected to assess the budget and trends of ozone and water vapour in the UT/LS, to reduce uncertainties on stratosphere/troposphere exchanges, to improve existing 3D CTM models and to better quantify the impact of subsonic aircraft. These results are of major concern for the evaluation of climate change. Prime Contractor: Centre National de la Recherche Scientifique, UMR 5560, Laboratoire d'Aerologie; Toulouse/France.
Das Projekt "Verbessertes Verstaendnis des Ozonverlustes in der Atmosphaere durch Zusammenarbeit mit dem Ozonverlust- und Validierungsexperiment SAGE III" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. Objective/Problems to be solved: What are the processes that lead to ozone loss in the stratosphere? How can we improve the atmospheric chemistry models so that we can obtain more reliable predictions of future ozone levels? It is of importance for the well-being of the European citizen to be able to predict future ozone levels over Europe. For this, we need a better understanding of the processes that lead to ozone depletion, and this understanding must be fed into the numerical models that predict future ozone levels. Scientific objectives and approach: The main objective is to obtain a better understanding of the processes that lead to stratospheric ozone loss in the Arctic during winter and spring. More specifically THESEO 2000-EuroSOLVE aims at: 1. Quantifying the degree and geographical extent of chemically-induced (anthropogenic) ozone loss in the Arctic vortex during the 1999-2000 winter. 2. Improving our knowledge on the role of lee-wave induced polar stratospheric clouds in the activation of passive reservoir compounds into active forms that destroy ozone. 3. Obtaining a more complete picture of the most important chemical species involved in chemical ozone destruction. 4. Closing the gap between measured and theoretically calculated ozone loss. 5. Creating the best possible synergy between THESEO 2000 and the US SOLVE campaign. These objectives are met through a combination of experimental observations in the field and numerical modelling. There are measurements taken from the ground, from balloons and from aircraft. THESEO 2000 and the American SOLVE campaign will be coordinated so that one gets the best possible coverage in measured species, and temporal and spatial coverage. Expected impacts: The project will, in combination with other THESEO 2000 projects and the SOLVE campaign, provide an unprecedented amount of information on key chemical and physical parameters throughout the lifetime of the polar vortex from autumn to spring. This gives us a good opportunity to test numerical models and to gain insight in the processes that lead to ozone loss. On a more political level the THESEO 2000 campaign represents a closer collaboration between European and American scientists than ever before. Data gathered through the two campaigns are shared in near real time between the two communities. This leads to a better scientific exploitation of the data collected during the winter of 1999-2000. Prime Contractor: Norwegian Institute for Air Research; Kjeller/Norway.
Das Projekt "Einfluss des Austausches zwischen Stratosphaere und Troposphaere auf den Transport und die Oxidationsfaehigkeit der Atmosphaere bei sich aenderndem Klima" wird vom Umweltbundesamt gefördert und von Technische Universität München, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Department für Ökologie, Lehrstuhl für Bioklimatologie und Immissionsforschung durchgeführt. Objective/Problems to be solved: STACCATO is a comprehensive study of stratosphere-troposphere exchange (STE) processes and their effect on atmospheric chemistry. STE is a key factor controlling the budget of ozone, water vapour and other substances in both the troposphere and lower stratosphere. Earlier studies of STE have concentrated primarily on the flux of air or trace constituents across the tropopause alone. Shallow exchange events are indeed partially reversible in nature and only produce compositional changes in the tropopause region. However, deep STE events are largely irreversible and have a highly significant and lasting impact on atmospheric chemistry through a substantial body of the atmosphere, even down to the earth's surface. Up until now, the importance of STE for the ozone budget relative to photochemical ozone formation from natural and anthropogenic precursor emissions, including those from aircraft, has remained uncertain. A comprehensive description of STE, which STACCATO seeks to provide, is thus a vital component for understanding the chemical composition of the atmosphere and its consequences. Scientific objectives and approach: STACCATO is undertaking a first detailed investigation of STE mixing of stratospheric and tropospheric air. Meteorological processes under investigation include the creation of fine-scale structures by chaotic advection, radiative decay of tracer filaments and mixing through turbulence in the free troposphere. The non-linear effect of this mixing on chemical processes is addressed with a box model as well as with a global model. The impact of STE on the oxidizing capacity of the troposphere, relative to other factors, is examined with two global chemistry models coupled to climate models. The fate of aircraft emissions is being addressed using passive tracer simulations and including these in the chemistry models. A new three-dimensional Lagrangian perspective of STE, focussing on deep exchange events, is being developed. The variability and recent trends of STE is being assessed, based on very high quality meteorological re-analysis data. Potential future changes to STE significance are being computed under scenarios of climate change obtained from simulations with two climate models. A major comparison of seven methods and models used to calculate STE is being carried out to find strengths and weaknesses of each approach and to identify reasons for discrepancies. A measurement dataset is being created to validate model results and to provide an independent estimate of the strength of STE. This includes the first long-term monitoring of two radionuclides, beryllium-7 and beryllium-10. Expected Impacts: Provision of an observational estimate of the strength of STE based on two years of radionuclide measurements. Analysis of the strength of STE and its variability during the last 15 years, based on Lagrangian models set up on meteorological re-analyses. Study of the possible changes in STE in a f
Das Projekt "Auswirkungen der Oxidation auf aromatische Verbindungen in der Troposphaere - EXACT" wird vom Umweltbundesamt gefördert und von Universität Wuppertal, Physikalische Chemie durchgeführt. Objective: Problems to be solved: Aromatic compounds are emitted to the atmosphere from transport and industrial sources and oxidised in the troposphere. This process has a substantial impact on the formation of ozone and of photochemical smog on a European scale, and on the oxidising capacity of the atmosphere and hence on global warming. The oxidation of aromatic compounds also leads to the formation of secondary aerosols, with impacts on health and on climate. A quantitative understanding of the chemical mechanisms for oxidation of the major aromatic compounds is needed for the construction of models for both predictive and legislative applications and for the assessment of environmental impact. Recent laboratory studies have demonstrated considerable uncertainties in our present understanding of the atmospheric oxidation of aromatics and have seriously questioned our ability to assess the atmospheric impact of aromatic compounds. The major aim of the project is a detailed laboratory investigation of the mechanism and the construction and application of a model, based on the experimental results, to assess the atmospheric impact of aromatic emissions on European and global scales. Scientific objectives and approach. The project consists of four main components: In the laboratory experiments, laser flash photolysis is used to probe the chemistry of the early stages of the oxidation process, using absorption spectroscopy. A key element is the behaviour of adducts formed by the addition of the hydroxyl radical to the aromatic compounds. The subsequent chemistry is probed using photochemical reactor studies, coupled with a range of analytical techniques, such as Fourier transform infra red spectroscopy and gas chromatography. A key component of the strategy is the synthesis of important intermediates to test the hypotheses that are developed. The overall description of the oxidation of the major volatile organic compounds emitted to the atmosphere is contained in a master chemical mechanisms (MCM). The experimental results allow revision of the aromatic component of the MCM, which is then used to design experiments to test the proposed mechanisms. These experiments are conducted in the European Photochemical Reactor (EUPHORE) at Valencia in Spain. The EUPHORE experiments are conducted under conditions close to those pertaining in the atmosphere and provide a credible test of the MCM and hence of the laboratory experiments. Crucial experiments include the yield of ozone in aromatic oxidation, but the extensive instrumentation in EUPHORE permits a wide range of detailed experimental checks on the MCM. In addition, other experiments allow investigation of the formation of secondary organic aerosol. Prime Contractor: University of Leeds, School of Chemistry; Leeds.
Das Projekt "Feststellung von Aenderungen in der Strahlungsrueckhaltung in den vergangenen Jahrzehnten" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Objective/Problems to be solved: Considerable uncertainties still exist in the magnitude of some of the main forcing factors which causes climatic change. There is a need to better quantify these factors e.g. those due to greenhouse gases, aerosols, stratospheric ozone and to solar processes. Scientific objectives and approach: The project aims to estimate the magnitude of temporal changes/variations in external forcing of climate, and to compare both the timing and the magnitude of the detected forcing anomalies with known and hypothesised variations in external forcing. Two different techniques to obtain the forcing will be used and compared, namely temporal changes in 6 and 24 forecast errors, i.e. forecast increments, and temporal changes in initial tendency errors obtained by assimilating the slow atmospheric normal modes obtained from re-analysis into a state-of-the-art climate model. The re-analysis data sets, which will be used, are the ERA15, ERA40 and the GEO-1 and GEO-2 data. The climate model to be used is the ECHAM model. Using re-analysis data, model tendency errors will be analysed to establish real forcing fields and to quantify forcing from processes not included in the model, i. e. stratospheric ozone, volcanic aerosols and desert dust. As a second step an improved ECHAM model, including parametrization of the processes mentioned above, will be used to assimilate the re-analysis data and the results will be used to estimate the performance of the parametrization schemes and the upgraded model. It is intended also to use this technique in a reverse mode to estimate e.g. concentrations of aerosols from volcanic eruptions. With the estimates of real forcings due to the various processes as far back in time as over the last 40 years the aim is to establish improved (insofar the accuracy of the data permits) estimates of dust/aerosol concentrations during dust/aerosol events. Such estimates are of particular interest for the earlier part of the period, where satellite observations of dust and aerosol loads are not available. In the same way, on a longer time scale, it will be investigated whether effects related to the 11 year sunspot cycle and solar processes of shorter duration and of stratospheric ozone depletion over the period can be quantified. Based on the above the various forcing estimates will be used to isolate the global warming signal from the increase in greenhouse gases (including water vapor), and to quantify to what extent greenhouse forcing has been offset by other forcings or processes during the period. Expected impacts: The project contributes to detection and attribution of climate change and its causes and its results could have important policy implications and impacts. The data sets produced and the model development work will contribute to the development of better climate models and climate change scenarios. Prime Contractor: Danish Meteorological Institute, Climate Research Division; Kobenhavn/Denmark.
Das Projekt "Eisenlagerstaetten und Naehrstoffe im Ozean - Fortschritt der globalen Umweltsimulationen" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Objective/Problems to be solved: The functioning of ocean ecosystems and their interaction with the global carbon cycle and the climate system is not very well known. Ocean Biogeochemical Climate Models (OBCM's) are still too simplistic to adequately describe observed changes in ocean biology and chemistry in space and time. Therefore large uncertainties remain concerning the carbon up-take by the ocean which also limits the predictability of the future carbon up-take. Scientific objective and approach: The work outlined seeks to better model marine ecosystems and the sources and sinks of C, N and other elements within those systems, assuming that a number of factors (notably light, N, P, Si, Fe) are co-limiting plankton blooms. This goal will be achieved through a combination of laboratory experiments, fieldwork and modelling. Laboratory work will target the predominant algal species of the major taxonomic groups and determine their growth as a function of multiple stresses, such as limitations of iron, light and macro-nutrients. This data will then be used to refine and improve ocean ecosystem models, with the aim to more accurately replicating observations of the natural system. New realistic OBCM' s will be developed for budgeting and exchanges of both CO2 and DMS, implementing (I) co-limitation by 4 nutrients of 5 major taxonomic classes of phyto-plankton, (II) DMS (P) pathways, (III) global iron cycling, (IV) chemical forms of iron and (V) iron supply into surface waters. Input from below of iron from anoxic sediments of coastal margins will be assessed along a 2-D vertical section from Europe into the centre of the north Atlantic. Input from above of Fe (II) dissolved in rainwater from Sahara dust blown over the central Atlantic will be quantified at sea, and related to observed plankton production, CO2 gas exchange and DMS emission. Different chemical forms of iron will be analysed and rigorous certification of all Fe in seawater data will be ensured. For 2 major DMS-producing algal groups the life cycle, Fe limitation, export production, CO2 uptake and DMS emissions will be synthesised from existing literature and laboratory experiments. Experimental data will be fed into an ecosystem model. Also DMS (P) pathway modelling will be carried out being expanded with 3 other groups of algal and DMS (P) pathways. The extended ecosystem model will provide reliable output for CO2/DMS gas exchange being implemented into two existing OBCM' s. Next climate change scenario' notably changes in Fe inputs, will be run, with special attention to climatic feedback (warming) on the oceanic cycles and fluxes. Expected impacts: Under the Kyoto Protocol, the European states have committed them selves to the quantification and prediction of future trends in the concentration of greenhouse gases in the atmosphere.. Prime Contractor: Netherlands Institute for Sea Research, Department of Marine Chemistry and Geology; Den Burg/Netherlands.
Das Projekt "Mineralstaub und Troposphaerenchemie" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Kernphysik durchgeführt. Objective/Problems to be solved: This project focuses on the transformation of atmospheric pollutants from Europe in the presence of mineral dust over S. Europe and Africa. Mineral dust is the single most abundant aerosol. It is injected into the atmosphere by the action of surface winds on dry soils from cultivated regions as well as arid regions, especially over Southern Europe, North Africa and in Asia. Estimations of the global source strength vary from ' 200 to 5000 Mt/yr, representing about 50 per cent of the total production of tropospheric aerosols by natural and anthropogenic sources together. At the global scale, the most important regions of dust emission are located near industrial regions with fast growing anthropogenic emissions of precursors of ozone and aerosols. Examples are the Sahel/Sahara (close to the Mediterranean Area) and the S. E. Asia deserts (close to Japan and to Eastern China). Reactions on the surface of aerosol particles (i.e. heterogeneous reactions) taking place in the troposphere can affect the radiative budget and alter the atmospheric content of key atmospheric species. Predicting the impact of changing anthropogenic emissions on atmospheric composition and climate, in Southern Europe and the Mediterranean Basin, requires an understanding of dust/pollution interactions. A few model studies have investigated atmospheric chemistry when dust and anthropogenic emissions interact showing a substantial effect on nitrate, sulfate and ozone. There is however a chronical shortage of laboratory data to back-up the (heterogeneous) reaction schemes used in present modeling studies. Furthermore, there is a lack of specific field data to show unambiguously the effect of dust/gas interactions: We propose a multi-disciplinary approach that involves a high degree of synergy between laboratory studies, two field experiments and a modeling strategy. This project will eventually perform a study of how the gas/dust interactions studied affect the IPCC (2000) estimates of radiative forcing by ozone and anthropogenic aerosols. Scientific objectives and approach: The project main objectives are: first, to quantify the impact of mineral dust on tropospheric photochemical cycles leading to ozone production and destruction, second to quantify the specific direct radiative effect of secondary aerosol (e.g. sulfate and organics) in the present of mineral dust. This results in an enhancement in our understanding and predictive capabilities regarding atmospheric composition change and climate. The multi-disciplinary approach of the project enables us to determine the efficiency and mechanism of the interaction of mineral dust with a number of important trace gases using laboratory experiments... Prime Contractor: Centre National de la Recherche Scientifique, Laboratoire des Sciences du Climat et de Environnement, Unite Mixte CEA-CNRS; Gif-sur-Yvette/France.
Das Projekt "Parameterisierung der indirekten klimatischen Wirkung von Aerosolen - PACE" wird vom Umweltbundesamt gefördert und von Freie Universität Berlin, Institut für Meteorologie, Institut für Weltraumwissenschaften durchgeführt. Objective: Problems to be solved: Reliable predictions of climatic change are impossible unless the magnitude and distribution of the anthropogenic perturbations of the climate can be quantified. The radiative effects of greenhouse gases are well understood; but the indirect effects of anthropogenic aerosols, that operate by altering cloud properties, are potentially significant and are very uncertain. Scientific objectives and approach: The project aims to address these problems directly, using the unrivalled data sets of co-located observations of aerosols, in cloud properties and radiative fluxes obtained during the ACE-2 field campaign. The measurements will be compared with cloud properties and radiative fluxes simulated by several climate models, with the objective of rigorously assessing the models and developing and testing more realistic schemes for representing aerosol-cloud-radiation interactions in climate models. The results of the ACE-2 Cloudy-column experiment will be examined and extended to the scales that are significant for GCM parameterizations, namely 100 km in space and 1/2 hour in time. The quality of the closure, that has been evaluated at the scale of the physical processes, will be evaluated at the GCM scale. The assessment will be focused on the four processes which are identified as the most important for the aerosol indirect effect (AIE), namely aerosol activation, microphysics/radiation interaction, drizzle formation and feedback, and cloud dynamics and homogeneity. The variables used for describing the physical processes will be examined in term of large scale statistics and the corresponding large scale variables will be defined. Special attention will be given to non-linear processes, which cannot be parameterized with the mean value and the standard deviation of the variables, but rather by tail of the distributions, such as vertical velocity for the CCN activation process or droplet concentration for the onset of precipitation. Various solutions will be proposed for the modellers to determine which ones are predictable. The values of these large scale variables will be calculated for each case study. Novel parameterizations based on large scale variables will be developed and tested versus the observations. The results of the data analysis, of satellite image processing and initialization fields extracted from the ECMWF analysis will be merged to form the data set for the models. Expected impacts: The results will contribute to narrowing the large range of uncertainly in model simulations of the indirect effects of anthropogenic aerosols, thereby facilitating more reliable predictions of climatic change. Prime Contractor: Meteo-France, Centre National de Recherches Meteorologiques; Toulouse.
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