The Rain is seamlessly and mindlessly on its way…..,.!
Continues to lash, leaving behind a spate of destructions;
Incidents of flooding,
People drown,
The uprooting of trees,
Minor landslides,
Properties damaged,
Vehicles get stuck on highways,
Plunge in water bodies,
Traffic is obstructed,
Houses are damaged by fallen trees,
Rivers overflow, houses submerged,
Even carcasses of elephants washed down the rivers,
Educational institutions remain closed!
The reason is Southwest monsoon, the highest rainfall season in Kerala which usually begins close to June 1 and comes to a halt by September 30 when the intensity of the rain subsides considerably, has made a sudden shift from its usual pattern, out of rage due to Global Warming; experts say.
The withdrawal of the southwest monsoon also heralds the advent of north-easterly winds bringing in the northeast monsoon to parts of peninsular Andhra Pradesh and Tamil Nadu. But there would be a gap of a period of around two weeks between the two monsoon seasons. As against this consistent pattern of season, this time, the India Meteorological Department is in a riddle and yet to announce the formal withdrawal of the southwest monsoon from Kerala.Similarly, the pre-monsoon season of mainly April-May and the post-monsoon season of September-December witnesses two to three tropical cyclones over the Arabian Sea every calendar year, an average of one storm in the pre-monsoon period, and a frequency of one or two strikes of storms in the post-monsoon period due to the presence of warm surface temperature in the Arabian Sea.
However, the weather pattern that we used to be familiar with, has been changing radically over the last few years. The sea surface temperature in the Arabian Sea is generally 1.5%-2% lower than in the Bay of Bengal. This is one of the main reasons for the fewer cyclonic circulations over the Arabian Sea.
A study by scientists of the Indian Institute of Tropical Meteorology (IITM) under the Union Ministry of Earth Sciences has found a 52% increase in the frequency of cyclones over the Arabian Sea between 2001 and 2019, while there was an 8% decrease in the same over the Bay of Bengal, as compared to the 19 years between 1982 and 2002.
In 2018 when Kerala witnessed the megaflood, the Indian Ocean witnessed seven cyclones of which three were from the Arabian Sea. In 2019 when the state witnessed the second back-to-back flood, the Arabian Sea contributed five cyclones of the total eight cyclones in the north Indian Ocean.
The IMD stats also show nine cyclones and depressions had formed in 2020, of which four were over the Arabian Sea. The number was seven in 2019. During the 1960-70 period, the Bay of Bengal witnessed 135 cyclonic storms and depressions while the number was 23 over the Arabian Sea. In the 2010-20 period, the number of cyclones and depressions over the Bay of Bengal nosedived to 59, while it increased to 33 over the Arabian Sea.
These figures predominantly act as a portent for Kerala to take long-term mitigating actions rather than knee-jerk reactions having no precautionary measures taken in advance, in every monsoon period. The climate change over the Arabian Sea holds a direct bearing on the rain pattern in Kerala which is evident from the rainfall that the state has received in the last four years. Though June and July are the months that brought copious rain to Kerala in the past, spells of very heavy rain for a short period have been seen in August and September in the last four years.
