Ship Based Observation of Ozone in the Tropical Mid-Troposphere During AEROSE 2009

Ozone is a chemical compound that can do either harm or good depending on where it is located. In the stratosphere, ozone shields biological life at the surface from harmful UV radiation, while elevated levels of ozone at the surface damages living organisms and is a major cause of respiratory diseases in humans. Ozone monitoring is therefore important in both the stratosphere and the troposphere. Ozone in the tropical Atlantic is a very important component of the global ozone budget, but is determined from a complex set of processes and is not well understood. Furthermore ozone in this region is under-sampled. During the summer of 2009, ozone data was collected across the Atlantic Ocean aboard the NOAA Ronald H. Brown vessel under the auspices of the AEROSE campaign. Analysis of the ozone sounding data collected and the possible source mechanism of the observed ozone concentration will be presented. Specifically determined will be the impact on ozone concentration of three different conditions that were encountered by the Ron Brown: biomass burning region, Inter Tropical Convergence Zone (ITCZ) and Saharan dust region. High levels of ozone are observed in the lower to mid troposphere near the equator as a result of production from transported biomass burning emission, while in the ITCZ low levels of ozone are observed in the mid troposphere due to transport of low surface level ozone from the Marine Boundary Layer. At higher latitudes in the dust region high levels of ozone are observed due to transport from West Africa and possible subsidence from the upper troposphere. This data an analysis should contribute to better understanding of the influences of ozone in this important region.