Condensation particle observations during the PNE/AEROSE 2009 trans-Atlantic mission

During the PNE/AEROSE 2009 field campaign (July 10 – August 11, 2009) a condensation particle counter, (model 3010, TSI incorporated) was deployed in the Howard University sampling van on the 02 deck of the NOAA ship Ronald H. Brown from July 16 to August 3 to collect measurements of total particle concentration in the marine boundary layer in support of the AEROSE science plan. The instrument was operated in an episodic sampling scheme, selecting days of sampling based on air mass outflows of interest. Data were collected on July 16-18, July 20-21, and July 25 to the 31 and August 1-3. Data were averaged in 30 minutes intervals and plots were generated for comparisons of particle concentration per day. Preliminary analysis of these data and observations obtained during daily weather briefings indicate that during July 20 – 21 an air mass from biomass fires in central West African countries was encountered. These observations are supported by satellite images (METEOSAT, Terra MODIS) and HYSPLIT back trajectory analysis. During this period the concentration of particles per cubic centimeters tripled from values that were 2000 particles per cubic centimeter July 19 to around 6000 particles per cubic centimeter July 20. The analyses also indicate a transition into a dusty air mass regime beginning July 25, that is observed to increase to a peak on July 27 with an average concentration for the day of around 5000 particles per cubic centimeter. These observations were also corroborated with HYSPLIT models and satellite retrievals (METEOSAT, Terra MODIS). On July 28, during the westward transit, we observed a decrease in the concentration of particles, but later observed a gradual increase as we encountered pockets of dust descending during trans-Atlantic transport.

This presentation will feature results from analysis of these data and include correlations with measurements from laser particle counters (CLIMET Instruments Company) and chemical concentrations from the Thermo Environmental Corporation gas analyzers to develop a full understanding of the aerosol loading and composition during this field campaign.