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Tropical Cyclones of the North Indian Ocean
Kumar, M.R.R. and Sankar, S. 2010. Impact of global warming on cyclonic storms over north Indian Ocean. Indian Journal of Geo-Marine Science 39: 516-520.

The authors write that "an important concern about the consequences of the global warming scenario is its impact on the frequency, the intensity and the duration of tropical cyclones," while noting that "theoretical and modeling studies indicate that tropical cyclone winds would increase with increasing ocean temperature."

What was done
To see to what extent the implications of these theoretical model studies harmonize with what actually occurred throughout the North Indian Ocean over the period 1901-2007, Kumar and Sankar employed "various datasets, such as the NCEP/NCAR Reanalysis dataset, the ERSST and the tracks of storms and depressions over the north Indian Ocean for different seasons based on the period 1901-2007," comparing "changes that occurred during the period 1951-2007 and the previous period, 1901-1951," while over the most recent of these periods they compared the sub-period 1951-1978 (epoch I) with the sub-period 1979-2007 (epoch II).

What was learned
First of all, the two researchers determined that "the frequency of storms and severe storms do not show a dramatic rise in spite of a substantial increase in the sea surface temperature in the Bay of Bengal from 1951-2007 compared to 1901-1951." Secondly, while noting that "the Bay of Bengal has been warming throughout the year during epoch II compared to epoch I," they report that "the number of both storms and severe storms, have decreased largely over the Bay of Bengal."

What it means
Kumar and Sankar say their results "clearly indicate that warm SST's alone are not sufficient for the initiation of convective systems over the Arabian Sea and the Bay of Bengal," noting that their results suggest a "decreasing trend in the frequency of storms over the Bay of Bengal, contrary to the popular belief that there will be an increase."

Reviewed 13 April 2011