Ocean surface and subsurface studies from space-based lidar measurements

The primary objective of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission has been studying the climate impact of clouds and aerosols in the atmosphere. However, recent studies have demonstrated that CALIPSO also collects information about ocean surface and subsurface. The objective of this study is to derive the ocean surface and subsurface backscatter profile at 532 nm from CALIPSO lidar measurements. The effects of CALIPSO detector's transient response on the attenuated backscatter profile were first removed in order to obtain the correct attenuated backscatter profile. The empirical relation between sea surface lidar backscatter and wind speed was used to estimate the theoretical ocean surface backscatter. Then the two-way atmospheric transmittance was estimated as the ratio between the CALIPSO measured ocean surface backscatter and the theoretical value. The ocean subsurface backscatter profile can be finally derived from the correct subsurface attenuated backscatter profile divided by the two-way atmospheric transmittance.