Institut für Meteorologie und Klimaforschung

Karlsruher Meteorologisches Kolloquium

Dozenten: Prof. Dr. T. Leisner, Prof. Dr. P. Braesicke, Prof. Dr. A. Fink, PD Dr. M. Höpfner, Prof. Dr. C. Hoose, Prof. Dr. P. Knippertz, PD Dr. M. Kunz, Prof. Dr. J. Pinto 

Veranstaltungskalender

 
Seminar

Atmospheric Ozone Trends: A Critical Review

Dienstag, 11. Januar 2011, 15:00-0:00
KIT Campus Nord, IMK-ASF
Gebäude 435, Raum 2.05
Ozone is a key trace gas in the Earth’s atmosphere: Stratospheric ozone protects the biota living at the Earth’s surface from the harmful solar ultraviolet radiation, ozone at the tropopause is a strong greenhouse gas, the most important precursor of OH radical (determining oxidation capacity), and the most important constituent of photooxidant air pollution. Photochemical air pollution was discovered around the end of World War II in the Los Angeles basin, where maximal concentrations (up to 680 ppb) were recorded in the 1970s. During the last decades highest ozone values in urban plumes decreased (or stabilized) in many industrialized countries because of air pollution legislation. Today highest ozone concentrations are found in the surroundings of megacities of developing countries (e.g. Mexico city, Soul). Background ozone concentration near surface at Arosa (Switzerland) and other rural sites in Europe has increased by approximately a factor two after World War II and the early 1990s most probably attributable to the large economic growth. Today intercontinental transport of tropospheric ozone in the Northern midlatitudes is an important research topic since increasing ozone precursor emissions of one continent might limit the effects of ozone precursor reductions in another. Growing ozone precursor emissions of South-East Asia led to a significant increase in baseline ozone (baseline ozone: not affected by local emissions) at Japanese sites (particularly in spring) and increases were found in the Western part of North America. Baseline ozone also increased during the 1990s in Europe (as measured at high mountain sites), but this increase stopped in the late 1990s. Based on data analysis it was suggested that the temporal evolution of baseline ozone over Europe after 1990 (when European ozone precursor emissions were peaking) might be caused by the modulation of ozone transport from the lower part of the stratosphere. Ozone changes in the upper troposphere/lower stratosphere are often determined from ozone sondes. Comparisons of regular aircraft measurements of GASP (Global Atmosphere Sampling Project, second part of 1970s) and MOZAIC (Measurement of Ozone and Water Vapor by Airbus in Service Aircraft Program) will be presented. Since the 1970s stratospheric ozone depletion by anthropogenic emissions of ozone depleting substances (ODS, such as chlorofluorocarbons) caused a decrease in stratospheric ozone, the most dramatic phenomenon is the Antarctic ozone hole. The emission of ODS was successfully decreased by the Montreal Protocol (1987). A rather simple statistical concept for documentation of the success of the Montreal Protocol will be presented together with new results using methods of extreme value theory for total ozone time series analysis. Ozone evolution of the lower stratosphere/upper troposphere is difficult to predict. Recent stratospheric numerical simulations expect enhancement of the Brewer/Dobson circulation (transporting ozone from the tropics to mid-latitudes) in future (“super recovery”). If the model predictions are correct ozone at the UT/LS (where ozone acts as an important greenhouse gas) could become a significant climate problem (when ODS will be removed from the stratosphere).
Diese Veranstaltung ist Teil der Reihe Karlsruher Meteorologisches Kolloquium
Referent/in
Prof. Dr. Johannes Staehelin

ETH Zürich
Institut für Atmosphäre und Klima
Veranstalter
Prof. Dr. J. Orphal
IMK-ASF
Karlsruher Institut für Technologie (KIT)
Karlsruhe
Tel: +49 721 608 29121
Fax: +49 721 608 24742
E-Mail: johannes orphal does-not-exist.kit edu
Servicemenü

Hinweise

"CS" - KIT-Campus Süd (Universität), Gebäude 30.23 (Physikhochhaus), Seminarraum 13/2

"CN" - KIT-Campus Nord (Forschungszentrum), Gebäude 435 (IMK), Raum 2.05

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