Sea Level Anomalies Variability During Contrasting Summer Monsoon Seasons Over Bay of Bengal

Abstract

During the summer monsoon period India received above normal rainfall in 2013 and below normal rainfall in 2009. The present study aims to understand the variability of sea level anomalies (SLA) and mesoscale eddies during the contrasting summer monsoon years of 2009 and 2013 over the Bay of Bengal. To accomplish this satellite derived daily gridded SLA product with 0.25° spatial resolution is examined. Oceanic mesoscale eddies are identified from the gridded SLA using widely adopted Okubo-Weiss parameter eddy detection method to separate areas between dominance of vorticity and strain. Evolution, mean, propagation, life cycle, kinematic properties and spatio-temporal variability of the cyclonic and anticyclonic eddies are examined during the years of 2009 and 2013. Significant differences in the SLA and mesoscale eddy activity are evident during the contrasting monsoon years. Bay of Bengal is warmer in 2013 than 2009, especially over the eastern bay. The results show that in 2009 cyclonic eddies are prominent over the western Bay of Bengal during the months of June and July. Dominance of anti-cyclonic eddies are evident over the northern and north-eastern Bay of Bengal in 2013. The present study extends current understanding by investigating the spatio-temporal variability of sea surface temperature, surface winds, turbulent fluxes and remote forcing effects. Our finding helps the understanding of Bay of Bengal circulation with summer monsoon season interannual variability.