1 A PACIFIC AEROSOL SURVEY- PART 1: A DECADE OF DATA ON PARTICLE PRODUCTION, TRANSPORT, EVOLUTION AND MIXING IN THE TROPOSPHERE

Integration of extensive aerosol data collected during the past decade around the Pacific Basin provides a preliminary assessment of aerosol microphysics for this region and cycling of aerosol in the troposphere.. These include aircraft based data collected as part of numerous field experiments supported by NASA, NSF and NOAA (GLOBE, ACE1, PEM-Tropics A&B). Although these experiments had diverse goals, most included extensive data on aerosol size distributions, optical properties (light scattering and light absorption) and chemistry. Vertical profiles of aerosol concentration, size distribution and light-scattering were used to characterize vertical structure from 70S to 70N. The in-situ data is placed in the context of meteorological regimes over the Pacific as well as processes associated with particle formation, growth and evolution and include dust, pollution, sea-salt, sulfates and clean cloud-processed air. The tropics commonly have low aerosol mass but very high number concentrations in the upper free troposphere (FT) that appear to form from sulfuric acid (nucleation) in convective regions and near cloud edges. These age and subside to become effective CCN when mixed into the marine boundary layer. Fewer number but larger aerosol are more evident in the mid-latitude FT. Thes