GUWAHATI, Aug 30 - The NE region is not getting its normal quota of rainfall during the peak month of August in the midst of monsoon season. Its rainfall amount is rather deficit. Why? Is it linked with the phenomenon of climate change? No, it cannot necessarily be linked with the phenomenon of climate change, said renowned climate expert Prof BN Goswami while talking to this newspaper. Prof Goswami is known for his studies on Indian monsoon dynamics.
Also a former director of the Indian Institute of Tropical Meteorology (IITM), Pune, Prof Goswami was the main scientist behind the discovery of the Indian Ocean Dipole (IOD). The IOD is a phenomenon in which the temperatures alternately oscillate between the western and eastern parts of the Indian Ocean. This phenomenon impacts the Indian monsoon tremendously.
Prof Goswami said, “There is a large-scale subsidence – downward movement – that is inhibiting formation of cloud. This is causing the present weather condition in the NE region. It is connected with the large-scale global circulation. This development may be linked with the year-to-year variation of global climate, but not necessarily with the phenomenon of climate change.”
Prof Goswami, a recipient of the Bhatnagar Award, the highest scientific award of the country, for his contribution to the study of meteorology, further said “We cannot directly link this development with the climate change phenomenon.”
Prof Goswami maintained that due to climate change, increased frequency of flooding events is witnessed in several parts of the country. But the long break in the monsoon rainfall activities over the NE region this time is to be viewed from the point of large-scale global circulation.
Global circulation is the worldwide system of winds through which the necessary transport of heat from tropical to polar latitudes is done.
Elaborating, he said that over the NE region there was an active monsoon spell in the month of July for about 15 days. That caused extensive flooding. After that, after the first week of August, a long break in monsoon rainfall activities set in. For the NE region, July-August is the peak period for monsoon rainfall activities. But this time, a long break in rainfall activities occurred in the month of August for about three weeks, resulting in rainfall deficiency over the region.
According to Regional Meteorology Centre (RMC), Guwahati, between July 6 and 17 this year, there was a very wet spell over the NE region. During this brief period, monsoon was active over the NE region with heavy to very heavy rainfall activities at isolated places and with occasional extremely heavy rainfall at isolated places. After that, monsoon activities fell over the NE region from the second fortnight of July.
This year, till August 29, each of Arunachal and Assam recorded a 13 per cent deficit rainfall, while Manipur recorded a deficit rainfall of 60 per cent, Meghalaya recorded a deficit rainfall of 18 per cent, Nagaland recorded a deficit of 27 per cent, Mizoram recorded a deficit of one per cent and Tripura recorded a deficit rainfall of two per cent till then.