Coastal upwellings and Mesoscale Eddies of the Western Arabian Sea: Some Biological Implications
S.A. Piontkovski*and S. Al-Jufaili
Sultan Qaboos University, CAMS,
PO Box 34, Al-Khod 123,
Sultanate of Oman
Satellite derived (SeaWIFS, MODIS, TOPEX/Poseidon, and Jason) chlorophyll-a concentration, sea surface heights, sea surface temperature, data on vertical profiles of temperature and salinity from the ARGO drifting floats, wind speed, the Dipole Mode Index, and historical data on sardine landings were employed, to analyze physical-biological coupling in the western Arabian Sea which is known for its vigorous eddy field affecting characteristics of biological productivity. Summer and winter monsoons impose different modes of mesoscale variability. In summer, the East Arabian
Current along with the currents of the Arabian Sea interior generates a dense field of eddies, where as in winter, eddies become less developed and less numerous. Therefore, the chlorophyll distribution is more heterogeneous spatially and more variable temporally during summer monsoon. Interannual changes of eddy field bear footprints of the impact of basin-scale atmospheric
anomaly (the Indian Ocean Dipole). Spatial-temporal characteristics of the eddy field are valuable tools in understanding seasonal and interannual fluctuations of sardine landings contributing ~ 50% to the fishery in the region.