L. S. Rowland und M. J. Molina weisen als warscheinlich nach, dass die langlebigen, weil auf der Erdoberfläche recht stabilen, Fluorkohlenwasserstoffe (FCKW) das Ozon der Stratosphäre zerstören.
Entdeckung, dass Stick(stoff)oxide das Ozon der Stratosphäre zerstören können und damit zuviel Ultraviolett-Licht (UV) die Erdoberfläche erreicht.
Das Projekt "Towards the prediction of stratospheric ozone II" wird vom Umweltbundesamt gefördert und von Universität Karlsruhe, Institut für Meteorologie und Klimaforschung durchgeführt. General Information: Most of the research effort in understanding the processes controlling the observed ozone decline have concentrated on the polar vortex and on the interaction of the polar vortex with mid-latitudes. There are other regions that are also important for future prediction of ozone change where significant uncertainty exists. Two such regions are the tropics, where the transport between mid-latitudes and the tropics is a key unresolved issue, and the mid-latitude lowermost stratosphere, where the amount of transport from the troposphere into the stratosphere is uncertain. There is a clear requirement for validation and development of three-dimensional chemical transport models in relation to these regions. This is the objective of this proposal. The improvement of our modelling capability in these regions is necessary for assessing the impact of anthropogenic emissions on stratospheric ozone and other trace gases. In particular, it is important to understand the impact of CFCs and aircraft emissions. An accurate modelling capability for stratospheric ozone is vital for good policy decisions in the European Commission and for international protocols. The proposal brings together a number of European modelling groups who are at the forefront of stratospheric research. They will examine the behaviour of 3-dimensional chemical transport models (CTMs) in these two key regions. The sensitivity to CTM formulation and resolution will be addressed. The output from the CTMs will be validated against recently collected datasets. The CTMs will be integrated using either winds from European Centre for Medium Range Weather Forecasts (ECMWF) analyses or from dynamical models. The results of the CTMs using winds from a number of different dynamical models will be compared. The dynamical models will include a state-of-the-art global circulation model (GCM), a mechanistic middle atmosphere model, and a simplified GCM. This will indicate how well these dynamical models can capture the key transport processes. Perturbation experiments will be performed in the dynamical models to assess the effects on tracer transport of the quasi-biennial oscillation, aerosol radiative heating from volcanic eruptions, and increased amounts of greenhouse gases. This proposal will benchmark low-resolution CTMs, which can be used in multi-year ozone assessment studies, against much higher-resolution CTMs. Multi-year integrations will be performed to assess the impact of increased aircraft emissions on stratospheric ozone. Prime Contractor: University of Oxford, Department of Atmospheric, Oceanic and Planetary Physics Clarendon Laboratory; Oxford.
Das Projekt "Towards the prediction of stratospheric ozone III: the partitioning of the NOy-components (EU-Projekt)" wird vom Umweltbundesamt gefördert und von Universität Karlsruhe, Institut für Meteorologie und Klimaforschung durchgeführt. Towards the prediction of Stratospheric Ozone III (TOPOZ III) The partitioning of the NOy components The partitioning of reactive nitrogene species (NOy) in the winter stratosphere is only poorly understood. This limits the scientific reliability of predictions of the ozone layer over decades. This project analyses the NOy partitioning using data from the MIPAS balloon experiment, the ENVISAT instruments MIPAS and SCIAMACHY operationally provided by ESA, and retrieved to a higher degree by UKARL, CSIC and UHB, which are compared to results of a variety of chemical transport models and data assimilation models. This comparison leads to improvements of the models involved which are passed to the CCM models of the DLR and ULAQ. Finally, these groups perform predictions of the ozone layer with a significant higher scientific reliability.
Das Projekt "Vermessung des Brom- und Iodgehalts in der unteren und mittleren Stratosphäre" wird vom Umweltbundesamt gefördert und von Deutsche Forschungsgemeinschaft durchgeführt. In unserem Vorhaben soll der Gehalt von Brom (Bry) und Iod (Iy) in der unteren und mittleren Stratosphäre bestimmt werden. Brom-Verbindungen sind für ca. 30% des Ozonverlusts in der Stratosphäre verantwortlich und damit ist eine regelmäßige Vermessung des stratosphärischen Bry angezeigt. Direkte Messungen in der mittlerenStratosphäre wurden aber seit 2011 nicht mehr durchgeführt. Zudem finden wir bei unseren jüngeren, flugzeuggetragenen Messungen von Bry (an Bord der NASA Global Hawk und des HALO Forschungsflugzeugs) in der tropsichen Tropopausenregion (TTL) und unteren Stratosphäre (UT/LS) etwa 2-3 ppt mehr Bry als aus lang- (Halone), mittel- (CH3Br) und kurzlebigen Bromverbindungen (VSLS) sowie deren Abbauprodukten zu erwarten ist. Die Gründe hierfür sind derzeit unklar. Unser Ziel ist es, die Messzeitreihe von Bry in der unteren und mittleren Stratosphäre wiederaufzunehmen und die entsprechenden Trends zu evaluieren. Insbesondere wollen wir untersuchen, ob die erhöhten Konzentrationen von Bry in der TTL mit Bry in der Stratosphäre kompatibel sind und was die Gründe für mögliche Differenzen sind. In Bezug of Iy weisen unsere früherenBeobachtungen auf Konzentrationen unterhalb der Nachweisgrenze hin, aber auch diese Untersuchungen liegen mehr als eine Dekade zurück. Neuere Arbeiten schlagen vor, dass die Bildung von höheren Iodoxiden zu einer Revision der bisher angenommenen Photochemie von Iod in der Stratosphäre führt, so dass ein erneuertes Interesse anstratosphärischem Iod besteht. Mit begrenztem zusätzlichem Aufwand wollen wir hier auch den Iy Gehalt (oder die entsprechenden Höchstgrenzen) in der Stratosphäre vermessen. Die Messungen sollen von einem Höhenforschungsballon (Steighöhe 30-38 km) aus mittels etablierter spektroskopischer Methoden in Sonnen-Okkultationsgeometrie durchgeführt werden. Es sind zwei Messflüge für Sommer 2021 von Kiruna, Schweden, und für Sommer 2022 von Timmins, Canada, aus geplant. Die Flüge und Kampagnen selbst werden durch die EU Infrastruktur HEMERA gefördert.
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 "MiKlip FAST-O3: Fast stratospheric ozone chemistry for global climate models" wird vom Umweltbundesamt gefördert und von Universität Berlin, Institut für Meteorologie WE03, Fachrichtung Dynamik der Atmosphäre, Arbeitsgruppe Atmosphärendynamik durchgeführt. In its first phase, MiKlip has made important research contributions and has developed an internationally competitive decadal climate prediction system. Building on these results, the overarching goal for MiKlip II is to establish and improve the decadal climate prediction system that eventually can be transferred to the German meteorological service DWD for operational use. MiKlip II is funded by the German Ministry for Education and Research (BMBF) with about 13 Mio. € for three years of collaborative research and a fourth year focusing on the operational implementation of the prediction system. MiKlip II involves 16 national partners from universities, research institutions and federal agencies.
Das Projekt "Teilprojekt 1, (Modul B)" wird vom Umweltbundesamt gefördert und von Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung - Institut AWI - Forschungsstelle Potsdam durchgeführt. Im Projekt FAST-O3 wird ein großes Defizit bisher existierender genereller Zirkulationsmodelle mit gekoppeltem Ozean (AOGCMs), wie sie für die Vorhersagen der IPCC-Studien oder zeitaufwändige Ensemble-Läufe genutzt werden, behoben: Aus Rechenzeitgründen enthalten diese Modelle keine interaktive Ozonschicht und sind nicht in der Lage, das antarktische Ozonloch und dessen Rückkopplung auf das Klima zu simulieren. Wir werden ein semi-empirisches, sehr schnelles stratosphärisches Chemie- und Transportschema entwickeln, welches es erlauben wird, eine interaktive Ozonschicht in existierende AOGCMs einzubinden. Dies wird zu einer erheblichen Verbesserung des Vorhersage-Skills des Gesamtsystems führen, da Prozesse in der Ozonschicht bedeutende Rückkopplungseffekte auf das gesamte Klimasystem haben. Ein bereits vorhandener und am AWI entwickelter Prototyp namens SWIFT, der bereits für polare Regionen geeignet ist, wird für extrapolare Regionen und für den Einsatz als Modul in einem generellen Zirkulationsmodell oder die Kopplung zu so einem Modell erweitert und weiterentwickelt. Dies umfasst: 1. Weiterentwicklung des Modells und Einbau globaler Ozonchemie, 2. Einbau eines schnellen Advektionsschemas auf Basis des ATLAS-Modells, 3. Kopplung zum EMAC-Modell und Ensemble-Läufe, 4. Validation gegen volle Chemie-Läufe, 5. Einbindung in das MiKlip Modellsystem.
Das Projekt "How is the evolution of stratospheric ozone affected by climate change, and how strong is the feedback? (SHARP-OFC)" wird vom Umweltbundesamt gefördert und von Universität Bremen, Institut für Umweltphysik durchgeführt. One major goal of this project is to analyse updated observational trace gas data together with stateof- the art models (CTMs and CCMs) in order to obtain a better understanding of the interaction between ozone and climate change and the underlying dynamical and chemical processes. The extended satellite, balloon and aircraft observations combined with improved model calculations (CTM and CCM) are used to further reduce the uncertainties in the bromine budget, in particular the contribution from VSLS (very short lived substances) and to further elucidate on the role of iodine in the stratosphere. Furthermore detailed studies on the long-term evolution (trends and variability) of observed stratospheric trace gases with foci on profiles of O3, NO2 and aerosols retrieved from SCIAMACHY are proposed. Future evolution of stratospheric ozone will be investigated using updated EMAC CCM model runs, some of them in combination with an interactive atmosphere-ocean feedback. In addition to issues on the climate feedback on future ozone, particular emphasis will be given to the increasing role of N2O and GHG emissions.
Das Projekt "GOME Assimilated and Validated Ozone and NO2 Fields for Scientific Users and for Model Validation GOA" wird vom Umweltbundesamt gefördert und von Universität Heidelberg, Institut für Umweltphysik durchgeführt. GOA is a short, two year project with a limited budget and a clear aim: Extend and improve the O3 and NO2 data products of GOME. Generate and distribute a five year data set of assimilated fields of ozone and NO2 based on GOME observations. This data set will be validated with other observations obtained during measurement campaigns and from monitoring networks. Confront this data set of two key chemicals of the atmosphere with output from global chemistry-transport models (CTM's) to improve their modeling capability of current and future changes of tropospheric and stratospheric ozone and chemically active greenhouse gases. The GOA objectives are: -To generate a 5-year data set of ozone fields (level-4 products) based on the measurements (available level-2 data) of the GOME spectrometer on board of the ESA ERS-2 satellite. -To validate these ozone fields with an extensive set of independent ground based and satellite observations. Improve and monitor the quality of the ground based observations. -To provide these fields to the scientific community by means of a web site and CDroms. -To estimate the tropospheric ozone content by using total column ozone data and ozone profile retrievals for GOME in a single assimilation. -To improve the GOME NO2 product by using position and time dependent model-predicted profiles of NO2 for the determination of the air-mass factor in the DOAS retrieval of NO2. -To validate this set of NO2 fields with independent ground based and satellite observations. -To provide assimilated NO2 (NOx) fields (target year 1997) to the scientific community. -To estimate the tropospheric NO2 column based on the assimilation and by exploiting the differences in spatial distribution of stratospheric and tropospheric NOx. Comparison with model results. -To identify NOx emission source strengths, by performing model studies and compare with the GOME NO2 observations. -To use this extensive combined data set of ozone and NO2 to validate the performance of chemistry-transport models concerning the modeling of the oxidation capacity, affecting chemically-active greenhouse gases, and the modeling of the seasonal and year to year variation in stratospheric ozone.
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