Interannual Consistency of Temperature Analyses in the Antarctic Stratosphere, 1998-2004
Abstract
Studies of chemistry in the polar vortices often rely upon accurate stratospheric temperatures. In particular, it is of interest to understand how interannual changes in polar vortex temperatures affect the chemistry in these regions, since this makes it possible to better discern to which extent observed interannual changes in the chemical composition of the vortices are meteorologically driven, and to which extent they may be caused by changes in long-lived species in atmosphere. In a recent paper by Hoppel et al. [2005], it was shown that during the Antarctic winters of 2001-2004 the amount of ozone at the top edge of the ozone hole was unusually high. An important goal of this paper is to determine whether there are any other indications of changes in the biases in the meteorological analyses which would lend further evidence to the conclusion of Hoppel et al. [2005] that the interannual ozone changes at ~20-22 km (~550K) were meteorologically driven. Most importantly, an analysis of radiosonde measurements does show a drop in the UKMO temperature relative to South Pole radiosondes near the top of the ozone hole between 2000 and 2001. There are also additional indications from the differences between POAM measurements and IMPACT model calculations, of aerosol extinction and dehydration, that there is a change in the UKMO temperature bias between 2000 and 2001. The ability to detect, in the POAM data, a slight systematic change in the UKMO temperatures indicates that the POAM is an excellent instrument for monitoring long-term changes in the Antarctic, and also shows that the analysis of such data is very sensitive to the stability of the temperature analysis. Fortunately, GPS radio occultation (GPS-RO) measurements from the CHAMP instrument provide a very good absolute calibration source. We will show comparisons between temperatures from the CHAMP instrument and the UKMO, ECMWF, and NCEP reanalysis temperatures for the years 2001-2004.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFM.A13D0969N
- Keywords:
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- 0340 Middle atmosphere: composition and chemistry;
- 0341 Middle atmosphere: constituent transport and chemistry (3334);
- 0342 Middle atmosphere: energy deposition (3334)