CHENNAI: The increase in episodes of extreme rainfall in India, including in Kerala, may have its roots in the Arctic nearly 9,000 km away. Sounds unrealistic? A recent study published in Nature journal by Indian and Norwegian scientists establishes a strong correlation between rapid melting of ice in the Arctic, and extreme precipitation here.
The study titled “A possible relation between Arctic sea ice and late season Indian Summer Monsoon Rainfall extremes” was led by Sourav Chatterjee, a scientist specialising in Atmosphere-Ocean Interactions Studies at National Centre for Polar and Ocean Research (NCPOR).
“Our findings suggest that during the years when there is reduced summer sea ice in the Barents-Kara sea region in the Arctic, the Indian summer monsoon exhibits an increased number of extreme rainfall events at its later phase – in September and October. The changes in upper atmospheric circulation due to sea ice loss, propagate from the Arctic region towards Asia, and contribute to enhanced moisture convection. The warm temperatures in the Arabian sea further provides moisture required for extreme rainfall,” Sourav Chatterjee told The New Indian Express.
The researchers have based their findings on historical rainfall data obtained from Indian Meteorological Department and sea ice data from National Snow and Ice Data Center (NSIDC). Ministry of Earth Sciences secretary M Ravichandran, who is one of the co-authors in the study, has hinted that the higher number of extreme events during this September may be partially caused by anomalous sea ice loss in the Arctic.
Must study sea ice, weather link , say experts
“The anomalous melting of Arctic sea ice this summer may have helped in establishing a favourable condition for enhanced moisture convergence and extreme rainfall during September and October,” Ravichandran said and added monitoring of Arctic atmosphere and oceanic conditions may help in improved prediction of monsoon.
Sourav said the Arctic responds to climate change more strongly than the rest of the globe.
The researchers called for further studies to understand the extent of sea ice contribution in developing the large-scale upper-level circulation anomalies.