Update on the global ozone climatology and on concurrent ozone and temperature trends

摘要

Abstract: An attempt is made to construct a zonal and monthly mean ozone climatology for use in general circulation models, based on a combination of ozonesonde and satellite observations. One important advantage of such a climatology is a more realistic ozone distribution around the tropopause, where heating rates and climate forcing are most sensitive to changes in gas concentrations. Also, a linear trend study is performed, for the periods 1970 - 83 and 1980 - 93 separately, on concurrent ozone and temperature data obtained from a selection of ozonesonde stations. On average for northern polar- to mid-latitudes, these trends are insignificant for stratospheric ozone and temperature in the first period, but for the second period show a stratospheric ozone depletion and stratospheric cooling of around $MIN@0.5%/year and $MIN@0.15 K/year respectively. As for the troposphere in the same region, ozone shows an increase (approximately 1.5%/year) in the mid-troposphere but temperature trends are insignificant over the first period, versus no ozone trend but a clearly significant near-surface warming (approximately 0.2 K/year) in the second period. This average situation is however not representative for the separate regions it is composed of, i.e., Canada (4 stations), Japan (3 stations) and the U.S. (1 station). Above Syowa station at the Antarctic coast, the acceleration in stratospheric ozone depletion as well as stratospheric cooling over the past two decades is clearly evident: from hardly significant ozone and temperature trends in the first period to values of up to $MIN@4%/year and $MIN@0.4 K/year respectively in the second period. In regions where near-surface ozone increase is evident over the past two decades, it is often accompanied by a significant near-surface warming.!26