Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 6 11 2006 10.5194/acp-6-3243-2006 http://www.atmos-chem-phys.net/6/3243/2006/ http://www.atmos-chem-phys.net/6/3243/2006/acp-6-3243-2006.html http://www.atmos-chem-phys.net/6/3243/2006/acp-6-3243-2006.pdf 3243 3256 2006-08-07 A study on the aerosol extinction-to-backscatter ratio with combination of micro-pulse LIDAR and MODIS over Hong Kong Q. S. He C. C. Li J. T. Mao A. K. H. Lau P. R. Li Department of Atmospheric Sciences, School of Physics, Peking University, Beijing, China The Institute for the Environment, the Hong Kong University of Science and Technology, Hong Kong, China Center for Satellite Remote Sensing and Measurement, Shanghai Meteorological Bureau, Shanghai, China Weather Modification Office, Shanxi Meteorological Bureau, Taiyuan, China The aerosol extinction-to-backscatter ratio is an important parameter for inverting LIDAR signals in the LIDAR equation. It is a complicated function of the aerosol microphysical characteristics. In this paper, a method to retrieve the column-averaged aerosol extinction-to-backscatter ratio by constraining the aerosol optical depths (AOD) from a Micro-pulse LIDAR (MPL) by the AOD measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. Both measurements were taken on cloud free days between 1 May 2003 and 30 June 2004 over Hong Kong, a coastal city in south China. Simultaneous measurements of aerosol scattering coefficients with a forward scattering visibility sensor are compared with the LIDAR retrieval of aerosol extinction coefficients. The data are then analyzed to determine seasonal trends of the aetrosol extinction-to-backscatter ratio. In addition, the relationships between the extinction-to-backscatter ratio and wind conditions as well as other aerosol microphysical parameters are presented. 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