There has been growing interest in the upper troposphere and lower stratosphere (UTLS) region in the atmospheric scientific community over the past few years for various reasons. They include concerns about increase in emissions, in particular NOx, from subsonic and supersonic aircrafts, which normally fly in this region and variations of ozone trends with height as well as spatial variations. Different 3-D global chemistry and transport models have estimated a NOx perturbation of 20-70% in the 8-12 km layer, causing an increase in O3 concentration by 2-9% through photochemical reactions. Observed trends in ozone shows interesting features with large decreases in the lower stratosphere at high and mid latitudes in both hemispheres, while the trends in the troposphere shows regional differences with a positive trend over Europe, a negative trend over Canada and no statistically significant trend over North America. However, most of the results on trends and seasonal variation of ozone are based on the data collected at mid-latitudes and Canadian Arctic stations. There are no reported reliable long-term measurement series of ozone in the European Arctic mainly because of the paucity of the long-term measurements of ozone. Most of our understanding on European Arctic ozone is based on results from a series of large campaigns, for instance EASOE, SESAME, THESEO, SOLVE, conducted in the European Arctic augmented by some other small campaigns. So in this talk, I will discuss about variations of ozone (annual as well as interannual) over northern Europe using a relatively long-term database of 7 years. I would also like to discuss the relation between ozone and potential vorticity. Further, I will present preliminary results on the climatology of tropopause folds at high latitudes. ERROR: Success
Created 2003-06-02 16:27:21 by Last changed 2003-06-23 15:51:35 by Mats Luspa
