ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-8-3593-2008 Sea surface wind speed estimation from space-based lidar measurements Hu Y. 1 Stamnes K. 2 Vaughan M. 1 Pelon J. 3 Weimer C. 4 Wu D. 5 Cisewski M. 1 Sun W. 1 Yang P. 6 Lin B. 1 Omar A. 1 Flittner D. 1 Hostetler C. 1 Trepte C. 1 Winker D. 1 Gibson G. 1 Santa-Maria M. 1 Climate Science Branch, NASA Langley Research Center, Hampton, VA, USA Dept. of Physics and Enginerring, Stevens Institute of Tech., Hoboken, NJ ,USA Université Pierre et Marie Curie, Service d'Aeronomie/IPSL, Paris, France Ball Aerospace & Technologies Corp., Boulder, CO, USA The Key Laboratory of Ocean Remote Sensing, Ocean University of China, Qingdao, China Dept. of Atmospheric Sciences, Texas A.& M. University, College Station Commerce Street,TX, USA 08 07 2008 8 13 3593 3601 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/8/3593/2008/acp-8-3593-2008.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/8/3593/2008/acp-8-3593-2008.pdf

Global satellite observations of lidar backscatter measurements acquired by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission and collocated sea surface wind speed data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), are used to investigate the relation between wind driven wave slope variance and sea surface wind speed. The new slope variance – wind speed relation established from this study is similar to the linear relation from Cox-Munk (1954) and the log-linear relation from Wu (1990) for wind speed larger than 7 m/s and 13.3 m/s, respectively. For wind speed less than 7 m/s, the slope variance is proportional to the square root of the wind speed, assuming a two dimensional isotropic Gaussian wave slope distribution. This slope variance – wind speed relation becomes linear if a one dimensional Gaussian wave slope distribution and linear slope variance – wind speed relation are assumed. Contributions from whitecaps and subsurface backscattering are effectively removed by using 532 nm lidar depolarization measurements. This new slope variance – wind speed relation is used to derive sea surface wind speed from CALIPSO single shot lidar measurements (70 m spot size), after correcting for atmospheric attenuation. The CALIPSO wind speed result agrees with the collocated AMSR-E wind speed, with 1.2 m/s rms error. Ocean surface with lowest atmospheric loading and moderate wind speed (7–9 m/s) is used as target for lidar calibration correction.

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