PANJIM: Despite receiving some respite from the dry spell the State has witnessed since Friday, Goa’s rainfall deficit is still 25 percent. While the normal rainfall is 2788.33 mm, the State has so far registered 2104.5 mm of rainfall accounting for a rainfall departure of 25 percent from normal.
Speaking to the Herald, Dr. Ramesh Kumar, Chief Scientist and Coordinator for the Physical Oceanography Division at the National Institute of Oceanography (NIO) said one of the major causes of the deficit was due to a phenomenon called El Nino.
“One of the major causes for rainfall deficiency for the whole of India is strong El Nino phenomenon in the Pacific Ocean,” he said.
El Nino is a natural phenomenon that occurs once every three to seven years that changes weather patterns due to shift in sea currents over the Pacific Ocean, which will have drastic change on the climate world over. A low pressure in the Pacific Ocean due to warm waters off the Western coast of South America increases the sea surface temperatures above normal by 0.5 degrees. The low pressure causes a diversion of flow of moist winds from the Indian Ocean to the western coast of South America. This in turn reduces the rainfall in India.
Dr Kumar said this situation may in fact be a dangerous one for the State and the country as a whole. “If there is a drought this year, it will affect the agriculture, hydroelectric power generation and even the drinking water in several States. Hence, the situation is quite dangerous in all aspects,” he said.
Scientists are however looking at the situation from a different perspective including modelling, diagnostics and also from an empirical modelling point of view. Several groups such as Indian Meteorology Department, Indian Institute of Tropical Meteorology and National Centre for Medium Range Weather Forecasting are working on looking into the situation.
While rainfall deficiency for two consecutive years is very rare, if 2014 and 2015 are considered consecutive drought years, it would be only after the case in 1986 and 1987. “Usually a drought year is followed by a normal or excess year,” said Dr Kumar.
Globally however, the scientist said the monsoon situation can change drastically. “The main change will take place in the spatial and temporal distribution of rainfall. We will have several regions where there will be no rainfall and several other areas which will have intense rainfall events (rainfall more than 10 cm in a day),” he said.
