An Overview of the ACE-Asia Aerosol Characterization Experiment Intensive Observations During the Spring of 2001

The objectives of the ACE-Asia experiment are to 1) determine the physical, chemical, and radiative properties of the major aerosol types in the Eastern Asia and Northwest Pacific region and investigate the relationships among these properties, 2) quantify the interactions between aerosols and radiation in the Eastern Asia and Northwest Pacific region, and 3) quantify the physical and chemical processes controlling the evolution of the major aerosol types and their physical, chemical, and radiative properties. To achieve these objectives, scientists from 13 countries made intensive observations in the spring of 2001 using three ships, three aircraft, and dozens of surface sites. The observations were directed using aerosol forecasts from three chemical transport models and real-time lidar data, and were often coordinated with satellite scenes to allow for column closure experiments and ground truth. Most platforms supported coordinated measurements of aerosol chemical and physical characteristics, optical properties, and radiation. The surface and ship sites did time series measurements and long-sampling-time observations, while the aircraft did vertical profiles and large-area spatial mapping for comparison with models. Numerous platform intercomparisons were done to help in harmonizing the many data streams. The weather was very cooperative, providing us with two major dust storms (dust from one storm was transported to North America and the Atlantic Ocean), frequent regional dust layers, and pollution plumes. Among our many observations is that in the presence of dust, most of the soot and non-sea salt sulfate still reside in a submicron accumulation mode, even though the dust particles may be modified by coagulation with small amounts of soot and other pollutants.