Alladi Ramakrishnan Hall

A Threefold increase in Widespread Floods over India

Raghuram Murtugudde

University of Maryland

Indian monsoon is notorious for its nakhras with the spatio-temporal
distributions between the famed onset and the quiet withdrawal.
El Niņo and LaNiņa have positive and negative impacts respectively
but only about 50% of the times. Now it is obvious that the tropical
Atlantic also displays an El Niņo-Ike zonal mode variability which impacts
the Indian monsoon as well. The global feature known as the Intertropical
Convergence Zone or the ITCZ seems to the conveyor of tropical variability
and has a peculiar split personality over the Indian Ocean during boreal
summer months. Increased greenhouse gases are well manifest in the Indian
Ocean warming and aerosols/pollution appear to be damping the warming of
the land leading a decrease in the mean monsoon. But the extremes in the
monsoon have increased and also become more widespread. The causalities
are discussed as well as the good, the bad and the ugly of the models used
for forecasting and projecting the monsoons. The devastating Kerala floods
are analyzed in this context.