HR: 09:00h
AN: A21G-05 INVITED     [Abstracts]
TI: Equivalent Latitude as an Indicator for Dynamical Variability and Trends in ozone column and profiles
AU: Wohltmann, I
EM: iwohltmann@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, Potsdam, 14473 Germany
AU: * Rex, M
EM: mrex@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, Potsdam, 14473 Germany
AU: Brunner, D
EM: dominik.brunner@env.ethz.ch
AF: Swiss Federal Institute of Technology, Institute for Atmospheric Science, Schafmattstr. 30 ETH-Hoenggerberg, Zuerich, 8093 Switzerland
AU: Maeder, J
EM: joerg.maeder@env.ethz.ch
AF: Swiss Federal Institute of Technology, Institute for Atmospheric Science, Schafmattstr. 30 ETH-Hoenggerberg, Zuerich, 8093 Switzerland
AB: Short-term variability in ozone column at a given location is almost solely caused by dynamical changes connected to tropospheric pressure systems. Long-term trends and interannual variability of ozone are also influenced by these dynamical changes. We address two questions here, which are still under discussion: What is the impact of these dynamical changes on the observed long-term trend of ozone, and what is the quantitative contribution of the physical processes standing behind the dynamical variability to the trends and short-term variability? These processes are identified as horizontal isentropic transport and the vertical displacement of isentropes. We use a multiple regression model to analyze the variability of the total ozone column and of profile data here. The model for ozone column is based on a newly introduced explanatory variable using the equivalent latitude profile at a given location. After transforming the equivalent latitude profile into an ozone profile with the help of an ozone climatology, we integrate the ozone profile by using the pressures at the isentropic levels, thus incorporating the effect of compression and expansion. Ozone column data are taken from high quality stations of the Dobson spectrometer network. Profile data from ozone sondes is examined by the equivalent latitude profile alone. Results show that both horizontal advection and vertical changes (due to a compression or expansion of air parcels connected with convergence or divergence of mass) contribute about equally to the short-term variability in ozone column in all months of the year in mid-latitudes. About 30%--50% of the long-term trend in total ozone in Europe can be explained by long-term pressure changes, while long-term changes in horizontal transport are negligible.
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 3334 Middle atmosphere dynamics (0341, 0342)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005