Progress of Indian summer monsoon onset and convective episodes over Indo-Pacific region observed during 2009-2014
Summer monsoon onset progress from the oceanic region of Southeast Bay of Bengal / Andaman Sea (Oceanr) up to extreme south-western part of India (Kerala) for the years 2009 to 2014 is investigated. It is found that during this period, the dates of onset over Oceanr and Kerala and the time required for the monsoon advance from Oceanr to Kerala has shown a large variation (Table 1). An attempt is made to investigate the causes for such variations.The results indicate that intense disturbances which formed over north Indian Ocean in 2009, 2010, 2013 and 2014 and over west-north Pacific Oceanic region in 2011 and 2012 have contributed for the same. By taking case to case review, the study has discussed how the location of formation, intensity and movement of the disturbances which formed around the time of the monsoon onset over such regions of tropical Indo-Pacific have resulted rapid advance or revival from stagnation or even stagnations in the monsoon advance from Oceanr to Kerala. (S. P.Ghanekar, S. G. Narkhedkar and D. R. SIKKA, Mausam, 67, 4, October 2016).