In Chennai, the rainy season to begin on time
Posted on: 28/Sep/2019 9:58:22 AM
In India, we have been witnessing extreme effects of climate changes like prolonged dry spells followed by sudden excessive rainfall and intense storms etc.
It is now revealed that for parched Chennai this climate change could play an important role in bringing in the much awaited northeast monsoons. The onset of northeast monsoon might not be affected by the delay in the withdrawal of southwest monsoon because the withdrawal could be rapid. Point is one of the factors that would be driving it would be the climate change.
According to a professor Sridhar Balasubramanian, climate expert, IIT Bombay, in a phased manner, changes in the wind direction used to take place in the past. He spoke about how now there are many factors resulting in rapid change in the wind direction. He hinted that one of the factors might be climate change but was unclear regarding the exact cause. Point is if the withdrawal of the southwest monsoon starts in the next 2 days then it would get over by October 10 to 15.
Around 20th October, northeast monsoon could start and this was as per Mr. S. Balachandran, deputy director general, RMC, Chennai. He added that the southwest monsoon might continue for atleast 10 days. Indications of withdrawal of southwest monsoons are dry spell of five days at a stretch, an anticyclone in lower troposphere and a drop in the moisture levels. Around 1st September, withdrawal usually begins in Jammu and Kashmir plus in the western parts of Rajasthan is known. Later on, the withdrawal might occur in Delhi, UP, Gujarat, Maharashtra, Goa and Northeast India over a time of 3 to 4 weeks.
It must be noted that around the same time when the withdrawal of southwest monsoon axis drops up to 15 degree N easterlies would begin. There would be widespread rainfall in coastal TN and adjoining places before IMD declares the onset of northeast monsoon.
A circulation system in Gujarat has been responsible for light to moderate rains in the northwest regions and it is now said that this circulation system is the reason for the withdrawal to get delayed. Dissipation of circulation system could take place and withdrawal could begin soon. In the year 2007, withdrawal began on 30th September is known. The point is this delayed retreat could be seen equalling a 12 year old record now.
Rapid change in the wind direction could also be triggered by positive Indian Ocean Dipole, Indian Ocean counterpart of Pacific El Nino. This was as per Professor Sridhar Balasubramanian. He spoke about how winds are governed by local Indian Ocean factors and how global Pacific Ocean connection was also there. Finally, he stated that local factors play a huge role in the withdrawal.
For the lakes, this delayed withdrawal of monsoons might be good but for the agriculture it would be bad. The reason is the farmers plan a change of crop ahead of the winter season. There wouldld be normal monsoon in this 2019 and this was according to the South Asian Climate Outlook Forum of World Meteorological Organization.
