Sea Surface Wind Speed Inversion Based On CALIPSO Aerosol Production

Because of the excellent capability of aerosol detecting and well atmosphere penetrability, lidar backscatter signal acquired from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission can provide accurate information about ocean surface backscatter and the amount of atmospheric aerosol loading in three-dimensional (3D) space. These information can be used to investigate the relation between wind driven wave slope variance and sea surface wind speed combing with wind speed provided by Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) since the two satellites are both in A-train. Six months (January, April, July and October, 2007, and January and April, 2008) of the version 2 lidar level 1 data and version 3 lidar level 2 data are used. Aerosols optical thickness conduct of version 3 level 2 aerosols layer production is used to calculate the two-way atmospheric transmittance of lidar signal. The accuracy of high resolution sea wind speed inversed from the relationship is also discussed.Global penetrability statistics of CALIPSO over ocean laser samples were derived from the new CALIPSO version 3 level 2 5-km lidar cloud layer products between June, 2006 and May, 2010 and about 55.6% of the total lidar samples can be used to detect the information of the sea surface. Cloud-free sea surface lidar signals are chosen by analyze two parameters—Integrated Backscatter Coefficient(IBC) and the two-way atmospheric transmittance( T_a~2) derived from CALIPSO version 3 level 2 aerosols layer production which is also used to correct lidar signals.Effect of geographical distribution is also discussed to improve the accuracy of lidar signal. With the sea surface wind speed provided by AMSR-E and the lidar signals which are chosen and corrected, a new relation between wind driven wave slope variance and sea surface wind speed is investigated. The accuracy of the inversed sea surface wind speed is analyzed by comparing with other wind speeds not only the ones get from AMSR-E and measured data provided by NEAR-GOOS, but also the wind speeds which are inversed from Cox-Munk's relationship, Wu's relationship and Hu's relationship. The new relationship which is similar with Hu relationship is better than Cox-Munk relationship and Wu relationship. The error results appear different with different months. The bias is about 1.4m/s. The RMS results appear from -0.2m/s to 0.3m/s. The new relationship between wind driven wave slope variance and sea surface wind speed is applicative when CALIPSO nadir changes from 0.3 degree to 3 degree.