Comparison of scan-angle method and convective cloud differential method in retrieving tropospheric ozone from TOMS.

Tropospheric ozone, derived from the Scan-Angle Method (SAM) and the Convective Cloud Differential (CCD) method, exhibits a noticeable abundance over the South Atlantic, where it is associated with biomass-burning in the austral spring. This feature is also seen in the distribution of carbon monoxide observed from Measurements Of Pollution In The Troposphere (MOPITT). In the boreal burning season, however, the distribution of the results from SAM and MOPITT-CO present an enhancement related to the biomass-burning over North Africa that does not appear in the CCD results. The relationship of the results from SAM and MOPITT-CO is better than those of the results from the CCD and MOPITT-CO for the December-February period. Conversely, the latter relationship is better than the former for the October-November period. The two methods, SAM and CCD, show higher correlation in the southern burning season, but lower correlation in the northern burning season. The influence of biomass burning on ozone amounts is clearly seen in the SAM results of the elevated ozone over northern equatorial Africa during the northern burning season, but is not present in the CCD results.