Sunday, April 25, 2010

South west Monsoon forecasting ...!!

IMD's long range forecast has only one thing of interest, that is its prediction that this year its going to be 98% of long term average. But it does not specify which regions would get more rain and which regions would get less. As 98% would be a country wide weighted mean; and india is a big counry, there's still a possibility of some part/parts having droughts/less rain.
IMD should improve its forecast, make it more informative and make it more interactive. I see some room for improvement in these quarters. And one more thing: Why isn't IMD including weather data and readings from regions and countries like Pakistan, Nepal, Bhutan, Tibet,Bangladesh,Burma and Srilanka. My guess is, the readings from these regions/countries would definitely play a crucial in monsoon forecasting. Monsoon is regional phenomenon and monsoon winds do not recognize political boundaries.I am sure the premonsson conditions in pakistan and tibet plays as important role in monsoon generation process.
Posted by Mr. Neeraj
SAARC nations comprises India, Pakistan, Bangaladesh, Nepal, Myanmar, Bhutan and Srilanka and there is co operation on weather among SAARC nations.
Though Monsoon is regional, it spreads further into Asia up to China. That why it is known as Asian Summer Monsoon.
But contrary to your belief, the [SW]monsoon winds originate from SOUTHERN HEMISPHERE near 30 Deg South and 60 Deg East in south INDIAN OCEAN.(Say, near Mauritius)
[1] The Southern Hemisphere MASCERENE HIGH plays a crucial role in determining Asian Summer Monsoon winds.
[2] The position of this HIGH pressure depends upon ENSO
[3] Further ENSO has its influence of the Sea surface Temperatures in Eastern Pacific i.e East of 180 East International Date Line.
[4] The land heating (or the heat low)in Jacobabath in Pakistan
[5] The Sub Tropical Westerly Jet zonal flow & the Sub Tropical High [STH] position over Himalayas and Tibet etc. etc also matters. These climatological factors are also taken in to consideration along with major predictors. But their influence may be in lesser scales than compared to the influence of Masceren High, SOI and other major predictors.
Region specific LRF can be tried or attempted provided the local climatological influence is properly understood or accounted and ensemble evolved accordingly.
In our country other agencies lick C-DAC, Center for atmospheric Sciences [IISc], SAC and few Agricultural Universities including TNAU are releasing advance forecast about monsoon RAINFALL. More or less some of them are regional specific.

posted by Mr. Anonymous
Myanmar is not a SAARC member but Afghanistan is. And yes, i do have some knowledge about where SW monsoon starts. I was just pointing out to the fact that Pakistan and Tibet also plays a role and i feel that these things are not given due importance. Overall prediction of course depends on the important factors that you have pointed out. But other factors will surely help to fine tune the whole thing. And yes, though Burma and China are not in SAARC, i again like to point out that SW Monsoon does not recognize any boundaries.
And on another note, all the countries in this region and particularly those in SAARC should cooperate much more as the economy and livelihood of the people in these regions depend on SW Monsoon.Maybe India can provide some assistance in weather data collection in SAARC countries.
Posted by Mr. Neeraj

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