Aerosol impact on the South China Sea biogeochemistry: An early assessment from remote sensing

Abstract

Using 4 years' of aerosol optical thickness (AOT) and chlorophyll-a (Chl-a) concentration data from the NASA/ MODIS and SeaWiFS sensors, this work systematically explores the role that atmospheric aerosols play in the biogeochemistry of the South China Sea (SCS). The results suggest that the further away from the coastline, the greater the potential role for atmospheric aerosols would be as a nutrient source to stimulate the biological activities because the chances of having other sources of nutrient inputs (e.g., river run-off or upwelling) are lower. It is found that the highest correlated area (R ∼ 0.7) of the Chl-a and AOT time series is in the southern centre of the SCS basin, typically between 111-113°E and 8-10°N. Away from the basin centre, the correlation between the two time series is typically low, with R ∼ 0.2-0.3. It is found that since there are other more prominent nutrient sources (e.g., monsooninduced upwelling and convective-overturn) to support the biological activities, atmospheric aerosols become less critical as a nutrient source in regions away from the basin centre. Copyright 2009 by the American Geophysical Union.