Summary of Abstract Submission

Abstract Submission No. IO50-06-0019PresentationPoster

CHANGING PRODUCTIVITY TREND IN THE ARABIAN SEA

Prince Prakash*1, Satya Prakash2, M. Ravichandran2

1 National Centre for Antarctic & Ocean Research,Goa, India
2 Indian National Centre for Ocean Information Services,Hyderabad, India

ABSTRACT :

South-western Arabian Sea is the most productive region in the Indian Ocean. Some of the recent observations using ocean colour data have shown contradicting trends in ocean productivity over the Arabian Sea. Analysis of basin average time-series of satellite derived monthly Chl-a concentration over the Arabian Sea for a comprehensively longer time scale (1997-2010) does not show any appreciable trend. A detailed analysis of selective productive regions, however, indicates that productivity had been increasing during 1997-2003 but have decreased during 2004-2010 over the western Arabian Sea. Other productive pockets such as northern and south eastern Arabian Sea does not show any statistically significant trend. It is worth noting that though productivity has varied on the western Arabian Sea during the past 13 years, there is no appreciable change in wind over the region over the same time period. Sea level anomaly (SLA) along the Somalia coast, however, shows a decreasing trend during 1997-2003 while an increasing trend during 2004-2010. Our analysis suggests that sea level change, through its manifestation on the thermocline, have caused change in productivity trend over the western Arabian Sea. The earlier observed variability in productivity over this region is not an effect of the global warming but may be a part of the decadal oscillation. We certainly need a longer time record to identify the effect of recent climate perturbations.