During the TC4 mission from July 13 through August 9,2007, ECC ozonesondes were launched from Alajuela, Costa Rica [10.0°N, 84.2°W], Las Tablas, Panama [7.8°N, 80.3°W] and San Cristobal in the Galapogos Islands [0.9°S, 89.6°W]. Here we examine 42 sondes that reached 25 km or higher. All of these sondes were accompanied by high-resolution temperature measurements from either RS80 or RS92 Vaisala radisondes, and most of the sondes also had GPS winds as well. Taken together, the ozone profiles display a rich fine structure and lamination in both the upper troposophere and in the lower stratosphere that in many instances can be linked to dynamical features induced in the temperature and wind fields by gravity waves and larger scale features. To characterize the typical structure of the profiles close to the tropopause we note that profile most often crosses the nominal stratospheric threshold mixing ratio of 100 ppbv within a few hundreds of meters of the first significant temperature minimum, either at the coded tropopause or just below it. Not all profiles are of this character and across the dataset the altitude at which the profiles first reach 100 ppbv varied from 13.7 km to 16.4 km . In several notable instances, such as the sounding at Alajuela at 06 UT on August 7, the coldpoint lay at 17 km atop a 3-km deep adiabatic layer with nearly constant ozone mixing ratio near the nominal threshold value, suggestive of a layer formed by mixing of stratospheric and tropospheric air. We use the ozone data in conjunction with the temperature and wind data to examine this and other cases for evidence of mixing and more purely dynamical processes.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 0340 Middle atmosphere: composition and chemistry;
- 0341 Middle atmosphere: constituent transport and chemistry (3334);
- 0365 Troposphere: composition and chemistry;
- 0368 Troposphere: constituent transport and chemistry