The Hindu : Tamil Nadu / Chennai News : Met department clueless to date of monsoon withdrawal

Online edition of India's National Newspaper
Thursday, Dec 22, 2005

Tamil Nadu

Tamil Nadu - Chennai

Met department clueless to date of monsoon withdrawal

T. Ramakrishnan

December 27 normal date of withdrawal

CHENNAI: The Meteorological department is unwilling to set any date for the withdrawal of the northeast monsoon.

This is because of the complexity of the monsoon, senior meteorologists say. Though December 27 is taken as the normal date of withdrawal, the meteorologists are in no position to say whether the monsoon this year too will be over by that date. The deviation is 12-13 days, which is a fairly long period. Again, this only highlights the complex character of the monsoon.

On several occasions, the monsoon continued upto January, they add.

Difference

The meteorologists point out that there is a big difference between southwest monsoon and northeast monsoon, with regard to withdrawal.

In respect of southwest monsoon, an important factor taken into account is the change in wind circulation features. When easterlies take over, the process begins. This happens in October for southern peninsula and normally, by the middle of October, the southwest monsoon withdraws completely all over the country and subsequently, the northeast monsoon commences.

But, in the case of northeast monsoon, easterlies last till March-mid April. "So, rainfall over the entire State should cease (to arrive at the conclusion on the withdrawal)," says S. Sridharan, Deputy Director General of Meteorology, Regional Meteorological Centre, Chennai. (However, for statistical purposes, the department regards the period of June-September as southwest monsoon and that of October-December as northeast).

Carried out by the RMC's research unit, a study on the monsoon over the last 105 years (1901-2004) reveals that in one-third of the years, the northeast monsoon spilled over to January.

Printer friendly page
Send this article to Friends by E-Mail

Tamil Nadu