Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 10 1 2010 10.5194/acpd-10-1983-2010 http://www.atmos-chem-phys-discuss.net/10/1983/2010/ http://www.atmos-chem-phys-discuss.net/10/1983/2010/acpd-10-1983-2010.html http://www.atmos-chem-phys-discuss.net/10/1983/2010/acpd-10-1983-2010.pdf 1983 2003 2010-01-29 Estimating the maritime component of aerosol optical depth and its dependency on surface wind speed using MODIS and QuikSCAT data Y. Lehahn yoav.lehahn@weizmann.ac.il I. Koren E. Boss Y. Ben-Ami O. Altaratz Department of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv, Israel Department of Environmental Sciences, Weizmann Institue, Rehovot, Israel School of Marine Sciences, University of Maine, Orono, Maine, USA Seven years (2002–2008) of satellite measurements from SeaWinds aboard Quick Scatterometer (QuikSCAT) and Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Terra are used for providing a global view on the link between surface wind speed and marine aerosol optical depth. This study shows that away form the continents the correlation time between the surface winds and the marine aerosol exceeds 4 h and therefore the two measurements can be linked. A systematic comparison between the satellite derived fields at different locations over the World Ocean allows to: (i) separate the relative contribution of wind-induced marine aerosol to the aerosol optical depth (ii) identify a threshold wind speed for triggering maritime contribution to aerosol optical depth; and (iii) extract an empirical linear equation linking marine aerosol optical depth and wind intensity. Wind induced marine aerosol contribution to aerosol optical depth is found to be dominated by the coarse mode elements. The threshold wind speed for triggering emission of coarse maritime aerosol is remarkably consistent with an average value of 4.1±0.1 m/s. When wind intensity exceeds the threshold value, coarse mode marine aerosol optical depth is linearly correlated to the surface wind speed, with a consistent slope of 0.0082±0.0004 s/m. 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