Relationship between wind speed and sea salt aerosol production: A new approach

Abstract

A relationship between ocean surface wind speed and sea salt aerosol production is established through a study carried out using the aerosol flux continuity equation by introducing satellite data on aerosols and ocean surface wind speed into it. This mathematical approach eliminates interferences from background aerosols and aerosol variations due to advection and convergences/divergences in wind field and correctly estimates the rate of sea salt aerosol production by winds. To avoid oceanic biogenic sources and transport from other oceanic and land regions, the study is done over ocean sites substantially remote from the continents with low chlorophyll concentrations (<0.06mg/m3) and restricting to aerosols in the bottom layer (<0.5km altitude) of the atmosphere. The surface wind speed is found to correlate better with the estimated aerosol production rate (RWS=0.99, p<0.0001) than with the bottom layer aerosol optical depth (RWB=0.97, p<0.0001). Aerosol production is observed at wind speeds even below 4m/s and the production rate is found to follow a linear relationship with ocean surface wind speed with a slope 0.0053 and an intercept 0.0163 for low as well as high winds.