Deprecated (16384): The ArrayAccess methods will be removed in 4.0.0.Use getParam(), getData() and getQuery() instead. - /home/brlfuser/public_html/src/Controller/ArtileDetailController.php, line: 150
 You can disable deprecation warnings by setting `Error.errorLevel` to `E_ALL & ~E_USER_DEPRECATED` in your config/app.php. [CORE/src/Core/functions.php, line 311]
Deprecated (16384): The ArrayAccess methods will be removed in 4.0.0.Use getParam(), getData() and getQuery() instead. - /home/brlfuser/public_html/src/Controller/ArtileDetailController.php, line: 151
 You can disable deprecation warnings by setting `Error.errorLevel` to `E_ALL & ~E_USER_DEPRECATED` in your config/app.php. [CORE/src/Core/functions.php, line 311]
Warning (512): Unable to emit headers. Headers sent in file=/home/brlfuser/public_html/vendor/cakephp/cakephp/src/Error/Debugger.php line=853 [CORE/src/Http/ResponseEmitter.php, line 48]
Warning (2): Cannot modify header information - headers already sent by (output started at /home/brlfuser/public_html/vendor/cakephp/cakephp/src/Error/Debugger.php:853) [CORE/src/Http/ResponseEmitter.php, line 148]
Warning (2): Cannot modify header information - headers already sent by (output started at /home/brlfuser/public_html/vendor/cakephp/cakephp/src/Error/Debugger.php:853) [CORE/src/Http/ResponseEmitter.php, line 181]
LATEST NEWS UPDATES | All that showers is not monsoon! -Vidya Venkat

All that showers is not monsoon! -Vidya Venkat

Share this article Share this article
published Published on Jun 12, 2016   modified Modified on Jun 12, 2016
-The Hindu

The direction of the wind, intensity of the rain and several other factors go into determining whether a rainy spell qualifies as monsoon.

In our eagerness for monsoon to arrive, any long drizzle may make it seem as though the annual rainy season is finally here. But not all rain spells that arrive in June qualify to be monsoon showers. For example, the sudden showers that greeted a parched Chennai on Monday and Tuesday could not be referred to as monsoon showers, even though they occurred on the dates when the monsoon was estimated to hit India (in Kerala) first.

On June 8, the India Meteorological Department (IMD) announced that the monsoon had finally arrived in India based on the criteria they have formed to determine its onset. Kerala received the kind of heavy, full-day monsoon shower that is characteristic of the seasonal spell of rain on that day.

Explaining the key difference between pre-monsoon showers and monsoon showers, D.S. Pai, head of IMD’s Long Range Forecast division, told The Hindu that pre monsoon showers are usually convective rainfall, that is, they are heat induced rainfall.

“Such showers usually follow a few hot days, and occur generally in the evening or anytime after 12 p.m. But monsoon rain could arrive first in the morning or continue to pour throughout the day,” he said.

Monitoring

In order to define or distinguish between the different types of rainfall received around the time of monsoon onset, 14 monitoring stations situated in Kerala measure various weather indices such as the direction of the wind, its speed, intensity of rain, and atmospheric pressure*. The onset of monsoon over Kerala is announced when from light pre-monsoon showers; the first sudden increase in rainfall is observed.

Criteria

The IMD’s criteria for announcing monsoon arrival requires that 60 per cent of the 14 stations record more than 25 mm. of rainfall for two consecutive days.

Monsoon winds must flow in the south-westerly direction and atmospheric pressure* at the height at which these winds form (approximately 4.5 km above the sea level) should measure about 600 hecta pascal, the unit of measuring pressure. Wind speed should be at least 16-20 knots† and there should be good clouding close to the Arabian Sea,” Mr. Pai explained.

The outgoing long-wave radiation or the amount of electromagnetic radiation emitted as energy from earth and its atmosphere to space in the form of heat is also a criterion for declaring monsoon. Only if at least three of these criteria are fulfilled, monsoon is declared to have arrived.

Please click here to read more.

The Hindu, 10 June, 2016, http://www.thehindu.com/news/national/on-the-factors-that-determine-a-monsoon/article8713283.ece


Related Articles

 

Write Comments

Your email address will not be published. Required fields are marked *

*

Video Archives

Archives

share on Facebook
Twitter
RSS
Feedback
Read Later

Contact Form

Please enter security code
      Close