Sunday, 9 February 2003
Comparisons of ozonesondes at Irene, Natal, and Ascension Island: The influences of biomass burning and lightning
Tropospheric Ozone levels at three sites, and fire and lightning flash counts in several areas of South America and Africa, have been examined. For each of these datasets, information was collected between 1997 and 2001, during the months of March through August. The objective is to find relationships between lower tropospheric Ozone mixing ratios and biomass burning, and upper tropospheric Ozone mixing ratios and lightning at three sites, Irene, Natal, and Ascension Island. Additionally, horizontal transport of pollutants was examined using streamline figures at the 925, 700, 500, and 300 hPa pressure levels in these areas. Several preliminary results consist of: (1) Lightning in Western Africa during March, April, and May and lightning in Central Africa during June, July, and August contribute to elevated Ozone levels in the upper troposphere at Natal. (2) High Ozone levels at Irene in the 500 hPa – 300 hPa layer are caused by lightning in a region of Southern South Africa. (3) In the lower troposphere at Ascension Island, Ozone is likely cause of fires located in Central Africa during March through August, yet in the upper troposphere, the source of Ozone at Ascension Island can be either lightning and/or biomass burning from regions of both South America and Africa due to its location in the Atlantic Ocean. These and other results will be presented in greater detail.