PANJIM: With Goa registering a deficit rainfall trend for more than five consecutive years, the Indian Meteorological Department (IMD) local observatory is likely to conduct a scientific study to assess the impact of climate change on the south-west monsoon over the coast, by gathering rainfall data of the last 100 years. The just-concluded monsoon season, which kicked-off on surplus note, ended with 19 per cent deficit.
After initial spells of surplus rains in the first 45 days of the monsoon, the State failed to touch even the 100-inch mark in the four-months ending September 30. The total seasonal rainfall for the season stood at 2410.5mm, which is a 19 per cent in deficit of the average 2917.7mm. The deficit, which hit the season in mid-July and which stood at 9 per cent, mounted to 14 per cent in August and 17 per cent in September. In fact, September, which is considered as the recovery month of the season, received 67 per cent less rainfall than normal.
“The 19 per cent deficit is within normal range. But yes, the increasing trend of a deficit rainfall is something to worry about,” IMD Goa Director M L Sahu told Herald.
Goa has been receiving a deficit rainfall since 2015, wherein the deficit was 20 per cent. For that year, State had received 2387.9mm rains. In 2016, the deficit dropped to 1 per cent, with total rains of 2955.9 mm. However, the deficit jumped back to 14 per cent with 2555.2mm of rains in 2017. The rainfall deficit was also recorded in 2012.
“Goa has been witnessing deficit rains for five years now. There are annual climatic variations. But we need to assess whether there is any impact of climate change. For that, we need to conduct a study by collecting data of over 100 years. It is long study but we have to conduct it,” Sahu said.
“Though, there is possibility of climate change impact, we cannot say it at this point without conducting any study,” he added.
The month of September, which normally receives average rainfall of 280mm, recorded only 92.3mm rains, which is 67 percent deficit. IMD was looking at September to review the deficit trend to some level.
When contacted, NIO scientist Ramesh Kumar said that rainfall is a highly variable parameter that varies from one meteorological subdivision to another. “Not necessary that the deficit trend will continue even in future,” he said. The scientist said that while Goa received deficit rains, Kerala saw rains much above average. The withdrawal of S-W monsoon will begin from October 6.
