GUWAHATI, Nov 11 - Rainfall activities in the NE region of India are not overwhelmingly controlled by the summer monsoon. The rainy season in this part of the globe begins from early April and may continue well after the summer monsoon withdraws from the rest of the Indian sub-continent, whereas the summer monsoon comes to the sub-continent in early June, said noted physicist Prof Ananda Kumar Barbara.
Prof Barbara, who is leading a number of research works, some of which are connected with thunderstorm and rainfall-related activities in the NE region, also maintained that the effect of global warming on the rainfall pattern of the NE region may be unique and quite peculiar.
Moreover, he said cyclonic activities in the Bay of Bengal may lead to stormy weather conditions in the NE region. But usually, such cyclonic conditions give rise to severe weather conditions in the east coast of the Indian sub-continent. In this coastal region, the impact of such cyclones may be quite serious.
Prof Barbara asserted that these days uncertainty prevails over the monsoon rainfall in this part of the globe. Monsoon rain may or may not occur, as it used to be in the past, in this part of the globe as was seen in 2009, he said.
The occurrence of rain in this region is coupled with the strength of the trade wind and heat input in the Pacific Ocean. The effect of global warming on the rainfall pattern of the NE region may be unique and quite peculiar, he observed.
Commenting on the effect of the El Ni�o Southern Oscillation (ENSO) on the rainfall patterns of the NE region, Prof Barbara said that when the atmospheric pressure goes low in the West Pacific, that is, in the area covering Indonesia, Malaysia and Singapore region, a rainy condition is generated in the South East Asian zone.
This situation gives rise to a very disturbed wind pattern as seen in the satellite pictures. Rainfall in this zone increases as a consequence. But when the situation reverses, that is, the pressure becomes low near the South American East Coast, the SE Asia experiences a shortfall in rain, said Prof Barbara, referring to research done in these areas the world over.