Das Projekt "Messungen und Modellierung von Ozon und aktiven Spezies von Fruehjahr bis Herbst - SAMMOA" wird vom Umweltbundesamt gefördert und von Forschungszentrum Jülich GmbH, Institut für Chemie und Dynamik der Geosphäre durchgeführt. Objective: Problems to be solved: There are still discrepancies between model prediction and observations of the year- round stratospheric ozone decline in mid and high latitudes. In summer, current models still severely overestimate ozone in the polar regions, and this appears as a major deficiency in our ability to model the complete ozone seasonal cycle. The springtime mid-latitude ozone depletion has not been satisfactorily modelled in a quantitative manner. This proposal hence aims at improving our understanding and modelling of ozone loss processes throughout spring and summer, in the northern mid and high latitudes. Scientific objectives and approach: The main scientific objective is to acquire a quantitative understanding of: (i) the mid-latitude ozone depletion accompanying the breakdown of the wintertime polar vortex, especially over Europe, and ii) the Arctic summer ozone deficit and its linkage to midlatitudes. The project relies on using an integrated approach combining ground-based and balloon-borne measurements, global satellite observations, as well as advanced chemical/dynamical modelling and data assimilation. Measurements of ozone, inert gases, or species actively involved in ozone chemistry, are made at three different stations in the Arctic throughout spring and summer. Observational techniques comprise ground-based lidar and infrared spectroscopic measurements, and light-weight balloon-borne instrumentation. Satellite observations complement these local, ground-based and in-situ measurements by allowing to characterise the global, evolving three-dimensional ozone distribution. The satellite data are globally integrated into a transport model through data assimilation. State-of-the-art numerical models are used to investigate the interaction of chemistry and mixing in the spring and summer stratosphere. These models are used to diagnose the ozone loss mechanisms and the overall transport of trace species in spring and summer. Correlative studies of the abundance of various trace species, either modelled or measured, allow to disentangle the effect of mixing from chemical sources and sinks. Expected impacts: The information to be provided by the field campaigns and model studies during SAMMOA will improve the quantification of ozone loss in the stratosphere, a key science priority in support of the Montreal protocol. This project will particularly impact on understanding of ozone depletion in spring and summer, when it is most harmful. It is indeed in the summertime, that human exposure to UV radiation is largest in middle latitudes. Modelling improvements shall result in better assessment and prediction of the ozone trend and recovery in support of regulatory protocols. Prime Contractor: Norwegian Institute for Air Research; Kjeller.
Das Projekt "Ozonvorlaeufer und deren Wirkung in der Troposphaere" wird vom Umweltbundesamt gefördert und von Universität Bremen, Institut für Umweltphysik durchgeführt. Objective/Problems to be solved: Tropospheric ozone has a dual role with respect to climatic changes. Ozone is itself a greenhouse gas and it also plays a key role in the production of the hydroxyl radical (OH), which controls the lifetime of many climatically important tropospheric gases. Tropospheric ozone and OH are produced as a result of photochemical processes, through reactions involving ozone precursors. The proposed project is defined in order to answer three main questions: first, can the surface emissions of ozone precursors, and their variability be accurately quantified? Second, how should the current observations of chemical species be optimally coupled with chemistry-transport models (CTMs) to quantify the global budgets of ozone precursors and ozone ? Third, how do future changes in surface emissions and proposed future scenarios influence the lifetime of greenhouse gases and ozone distribution ? The project will provide a quantitative basis for emissions, distributions and evolution of chemical tropospheric species for discussions related to policies aimed at improving the quality of air or at reduction of greenhouse species anthropogenic emissions. Scientific objectives and approach: The overall objective of the project is to quantify accurately the budget of ozone precursors using a combination of observations and state of the art CTM. The retrieval methods to derive accurately the tropospheric burdens of CO, CH4, NO2 and ozone from observations provided by the IMG/ADEOS and GOME instruments will be improved. High resolution inventories of emissions for ozone precursors will be developed. The ability of several European CTMs to reproduce current distributions will be assessed, through detailed comparisons between model results and observations. The impact of changes in ozone precursors on the tropospheric oxidising capacity and on the distribution of ozone will be quantified. The relative importance of anthropogenic versus natural emissions in the ozone production will be quantified. The inverse modelling approach for quantifying surface emissions will be further developed. These developments will yield an assessment of the accuracy of current inventories. The impact of emission mitigation policies on the distributions of methane and ozone will be quantified.. Expected impacts: The proposed project addresses issues that are central to our understanding of the causes of large-scale air pollution and climate change, and will provide a quantitative basis for reducing the environmental and climatic impact of human activities. The new tools and data bases we will develop will aid the understanding of changes in the composition of the atmosphere and their consequences. The emissions distributions we will optimise could be used as a starting point for discussions on emissions reduction policies... Prime Contractor: Centre National de la Recherche Scientifique, FU 0005 - Institut Pierre-Simon Laplace; Guyancout/France.
Das Projekt "Bewertung der Wirkung von Dimethylsulfid auf das Klima" wird vom Umweltbundesamt gefördert und von Universität Wuppertal, Physikalische Chemie durchgeführt. Objective/Problems to be solved: The proposed research programme is designed to resolve many of the outstanding key issues concerning the chemical transformation of DMS so that a reliable quantitative appraisal can be made of its contribution to CCN formation and consequently an assessment of the magnitude of its regulatory role in climate. Past work on the atmospheric chemistry has been instrumental in highlighting very specific processes, which need to be investigated in detail if a reliable assessment of the relationship between DMS, CCN and climate is to be made. The continuing improvement in analytical techniques now makes it possible to make high quality and high time resolution measurements of many species, both in the laboratory and in the field, which were previously either not possible or only with large error limits and poor time resolution. Scientific objectives and approach: The major objectives of the project are 1) to put constrains on the large uncertainties associated with current photochemical models by providing more accurate gas-phase kinetic and photochemical data on DMS oxidation chemistry. 2) Investigate particle formation from both DMS and DMSO. 3) Simultaneous high-time resolution measurements of dimethyl sulphide, oxidation products, halogen oxides, NO3 radical, and aerosol number/size distribution in 3 campaigns at sites with different geographical locations reflecting distinct aspects of DMS chemistry. 4) Use the data to determine the relative importance of the oxidants OH, NO3 and halogen oxides under different atmospheric conditions. 5) Use the laboratory data to construct a DMS chemistry module for CT-models capable of describing both the remote and polluted marine atmosphere and test of the models against the field data. The objectives will be achieved by a closely co-ordinated amalgamation of laboratory, field and modelling investigations. Expected impacts: The main deliverables of the project will initially be progressive constraints on kinetic/ mechanistic aspects of the oxidation chemistry of DMS and DMSO from laboratory and field experiments. This will be accompanied by high-time resolution field measurements of DMS, oxidation products, aerosols and other products relevant to the photo-chemistry. Based on this laboratory and field information a comprehensive gas/aerosol DMS-halogen-chemistry mechanism (g/a-DMS-HALO) module for incorporation in CT-models will be developed, which will be capable of describing DMS chemistry in both the remote and polluted marine atmosphere. The information can eventually be incorporated into global climatic models.
Das Projekt "System fuer die Beobachtung von Treibhausgasen in Europa" wird vom Umweltbundesamt gefördert und von Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Institut AWI - Forschungsstelle Potsdam durchgeführt. Objective: SOGE is an integrated system for observation of halogenated greenhouse gases in Europe. A network will be developed between four network stations, with full intercalibration. For PFC and SF, a technique for high-frequency measurements will be developed. These in-situ measurements will be combined with vertical column measurements. Trends in concentrations will be established. Integration of the observations with a variety of model tools will allow extensive and original exploitation of the data. The integrated system will be used to verify emissions in Europe down to a regional scale. The results can be used to assess compliance with the international protocols regulating the emissions, and they will be utilised to define criteria for future monitoring in Europe. Global models will be used to estimate impacts of the observed compounds on climate change and the ozone layer; namely radiative forcing and Global Warming Potential (GWP), and ozone destruction and Ozone Depletion Potential (ODP), respectively Environmental authorities and industry will be invited to a workshop for mutual exchange of information between the project participants and users. Prime Contractor: Norwegian Institute for Air Research; Kjeller/Norway.
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.
| Origin | Count |
|---|---|
| Bund | 66 |
| Type | Count |
|---|---|
| Förderprogramm | 66 |
| License | Count |
|---|---|
| offen | 66 |
| Language | Count |
|---|---|
| Deutsch | 66 |
| Englisch | 61 |
| Resource type | Count |
|---|---|
| Keine | 64 |
| Webseite | 2 |
| Topic | Count |
|---|---|
| Boden | 60 |
| Lebewesen & Lebensräume | 64 |
| Luft | 59 |
| Mensch & Umwelt | 66 |
| Wasser | 60 |
| Weitere | 66 |