Contrasting Chlorophyll concentrations in the Arabian Sea Compared to the South China Sea: Impact of Dust Storms

: The South China Sea and the Arabian Sea are both located in the north tropical zones, with similar latitudes (0-24°N). Seasonal Monsoon plays an important role in upper oceanic circulation in these two oceanic regions. But the distinct pattern of chlorophyll-a concentrations (Chl-a) is found in two oceans. Chl-a in the Arabian Sea is generally found to be higher than those of the South China Sea during summer (June-August). The Chl-a concentration in the Arabian Sea is found to show stronger inter-annual variability compared with those of the South China Sea using satellite data. The satellite data show higher atmospheric dust deposition, lower SST and strong wind speed in the Arabian Sea. The back-trajectories model calculation shows the transport of dust from the Arabian Peninsula which is very dominating during April - August. The good correlations are found between the index of dust precipitation and Chl-a, and between wind speed and Chl-a, that support the possible nutrients supply in the Arabian Sea due to transport of dust giving rise to higher Chl-a.