Somali Current and SWM

The winds over the Indian Ocean, north of 10 S,  reverse direction twice during any year. Over the north Indian Ocean, they generally blow from the southwest during May–September and from  northeast direction during  November–February,March–April and October being the months of transition with weak winds. The winds are much stronger during the summer  monsoon than during the winter monsoon. These seasonally reversing monsoon winds over the north Indian Ocean force a seasonally reversing [WATER] circulation in the upper ocean. The best studied of the seasonally reversing currents are the Somali Current (SC), which flows poleward (equatorward) along the coast of Somalia during the summer (winter) monsoon. During the summer monsoon, the monsoon current flows eastward as a continuous current from the western Arabian Sea to the Bay of Bengal.

What is upwelling: 

Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water. The increased availability in upwelling regions results in high levels of primary productivity and thus fishery production. Approximately 25% of the total global marine fish catches come from five upwellings that occupy only 5% of the total ocean area. Upwellings that are driven by coastal currents or diverging open ocean have the greatest impact on nutrient-enriched waters and global fishery yields. Somali current is one among the five upwellings in the globe. The cold deep water is brought to sea surface and thus the SST falls by several degree at once. This currents make gyre close to Kanyakumari during monsoon.  Somali current is an Indicator of onset of monsoon but seldom determines the SWM.