With fifth cyclone in Arabian Sea, 2019 equals 117-year-old record
The Arabian Sea has recorded five cyclones this year equalling a 117-year-old record, data from the India Meteorological Department (IMD) shows.
The latest weather system over the southwest Arabian Sea intensified from a deep depression to tropical Cyclone Pawan, which was declared by IMD on Thursday morning.
The Arabian Sea witnesses a normal of one cyclone per year. The last time five tropical cyclones were witnessed in a year was in 1902.
This year, very severe cyclonic storm Vayu was witnessed from June 10-17, very severe cyclonic storm Hikka from September 22-25, super cyclonic storm Kyarr between October 24 and November 2, extremely severe cyclonic storm Maha from October 30 to November 7, and presently Cyclone Pawan.
Cyclone Pawan developed as a well-marked low-pressure area on December 2.
As compared, the Bay of Bengal has witnessed only three cyclones—Pabuk, Fani and Bulbul—against the normal of four per year.
“The frequency of cyclones has been abnormally high this year for the Arabian Sea while it has been subdued for the Bay of Bengal. It is also a rare event to witness cyclones in December,” IMD’s director-general Mrutyunjay Mohapatra said.
The genesis of such weather systems depends on the factors like sea surface temperature, wind pattern and triggering weather events, meteorologist and PhD researcher at the UK’s University of Reading, Akshay Deoras, said.
“The sea-surface temperature has increased in the Arabian Sea compared to the baseline of 1981-2010, but the low-pressure activity in the region continues to be erratic. This suggests the importance of atmospheric conditions as well as triggering weather events,” Deoras said.
The post-monsoon cyclone season has been more active over the Arabian Sea with the formation of five cyclonic disturbances against the normal of one per year while it has been subdued over the Bay of Bengal with one cyclonic disturbance against the normal of 3.5 per year.
During pre-monsoon, there have been two cyclonic disturbances in the Arabian Sea against the normal of one per year while one in the Bay of Bengal only. This is the maximum number of cyclonic disturbances observed in the Arabian Sea, according to IMD.
Last such activity of post-monsoon event was witnessed in 1982 and 2011 with four cyclonic disturbances.
Experts said IMD’s data reaffirms repeated warnings of increased frequency of cyclones in the Arabian Sea in coming years by the United Nations Intergovernmental Panel on Climate Change (IPCC).
“Rather than living in denial, policymakers in the central government need to take note of these developments and come up with climate-resilient policies for coastal cities as the situation is expected to be worse in coming years,” said Anjal Prakash, coordinating lead author of a special report by IPCC in October.
Other meteorologists pointed out that 2019 has been a hall of fame year as far as weather dynamics are concerned with records been broken along several areas for the west coast of India.
“From above-normal rain to record the number of cyclones during onset and withdrawal of monsoon season, powerful super cyclones, twin cyclones in the Arabian Sea, and even rain during November and December, this has been a unique year,” Sridhar Balasubramanian, associate professor with IIT-Bombay’s department of mechanical engineering, said.