Monday, 15 January 2007: 2:00 PM
Comparison of AEROSE I and AEROSE II Surface Level Ozone Measurements and Ozonesonde Profiles within Saharan Dust and Biomass Burning Plumes
212A (Henry B. Gonzalez Convention Center)
Dust-ozone interactions are a rich area of investigation in atmospheric chemistry. For example, several recent studies have suggested that the presence of Saharan dust can have both positive and negative influences on atmospheric ozone concentrations. Characterization of ozone variability in the tropical marine environment can aid in validating and improving photochemical and chemical transport models, and provide insight into changes in the oxidizing and photochemical properties of the maritime atmosphere. The NOAA Center for Atmospheric Sciences at Howard University, in collaboration with NOAA/NESDIS, has conducted two shipboard experiments to examine the influence of Saharan dust on tropical Atlantic ozone concentrations and aerosol chemistry. AEROSE-I was a 27-day trans-Atlantic mission conducted in Spring 2004, whereas, AEROSE-II was 55-day mission that was conducted in Summer 2006. During both cruises, ozone and carbon monoxide were measured continuously along the cruise tracks. During AEROSE-II, twenty ozonesondes were launched along 23°W in order to characterize the vertical structure of ozone during summertime dust episodes. Satellite imagery and data analysis show that the AEROSE team was able to characterize multiple dust intrusions during both the Spring and Summer seasons. Analyses of aerosol mass density, element composition, and black carbon data sets reveal at least four distinct air mass regimes: background marine boundary layer, African dust, biomass smoke, and mixed African dust and biomass burning. AEROSE-II encountered less intense dust plumes but significantly more intense biomass burning plumes than AEROSE-I. A comparison of ozone datasets from both cruises and an analysis of the ozonesonde results will be presented.