Somali jet in the Arabian Sea, El Niño, and India rainfall

Abstract

Interannual variations of the Somali Jet in the Arabian Sea during 1988-99 were linked to El Niño and La Niña episodes and to India west coast rainfall. Onset dates and monthly mean strengths of the Somali Jet were described with Special Sensor Microwave Imager surface wind speeds. Each year the Somali Jet formed in a similar area in the western Arabian Sea, and always before the onset of monsoon rainfall in Goa. The average date of Somali Jet onset was two days later in El Niño events in comparison with La Niña conditions. Monthly mean strength of the Somali Jet was 0.4 m s-1 weaker during El Niño episodes than during La Niña intervals. When the monthly mean intensity of the Somali Jet was above (below) normal, there was an excess (deficit) of rainfall along the Indian west coast.