Observation of dust and anthropogenic aerosol plumes in the Northwest Pacific with a two‐wavelength polarization lidar on board the research vessel Mirai

Abstract

Dust and anthropogenic aerosol plumes from the Asian continent were observed in the Northwest Pacific (32.0° to 38.0°N, 146.5°E) with a two‐wavelength polarization lidar on board the research vessel Mirai during the MR01‐K02 cruise (May 14 to 28, 2001). Dust aerosols were identified from the aerosol depolarization ratio at 532 nm and the ratio of the backscattering coefficient at 1064 nm and 532 nm. High aerosol density air masses with a low depolarization ratio and a small wavelength ratio (indicating small particle size) were also detected in the plume. The distribution patterns of the dust and the spherical aerosols were conceptionally explained by the model prediction for dust and sulfate with the Chemical Weather Forecast System (CFORS). Aerosols with large particle size but with low depolarization ratio were also observed in between the layers of dust and sulfate. This indicates that the aerosols were possibly an internal mixture of dust and sulfate.