Thursday, April 07, 2005

Waiting for the rains...

The rains are here, even though these are pre monsoon showers. The monsoon is a big thing in India. If it rains, the agriculture sector does well, which in turn increases the purchasing power in the rural areas; they buy goods and there is prosperity all around. If there isnt, the reverse happens. Before it reaches India, the monsoon begins to stir up many months earlier in the warm currents in the ocean.

I found a good link here

...A monsoon is a term from early Arabs called the "Mausin," or "the season of winds." This was in reference to the seasonally shifting winds in the Indian Ocean and surrounding regions, including the Arabian Sea. These winds blow from the southwest during one half of the year and from the northeast during the other...

From there again

...monsoons share three basic physical mechanisms: differential heating between the land and oceans; Coriolis forces due to the rotation of the Earth; and the role of water which stores and releases energy as it changes from liquid to vapor and back (latent heat). The combined effect of these three mechanisms produces the monsoon's characteristic reversals of high winds and precipitation. Scientists say that the two key ingredients needed to make a monsoon are a hot land mass and a cooler ocean. In India, for instance, the land absorbs heat faster from the sun than the surrounding Indian Ocean does. This causes air masses over the land to heat up, expand, and rise. As the air rises, cooler, moister, and heavier air from over the ocean will replace it.. Over India, this damp, cool layer can be up to three miles thick. As the cool air arrives, the winds also shift. During the dry season, the winds blow offshore, from land to sea.

Then, as the monsoon begins, the winds blow onshore, from sea to land. In the case of the Indian Ocean Monsoon the first and third mechanisms produce more intense effects than any other place in the world...

...The Indian summer monsoon typically covers large areas of western and central India receiving more than 90% of their total annual precipitation during the period, and southern and northwestern India receiving 50%-75% of their total annual rainfall. Overall, monthly totals average 200-300 mm over the country as a whole, with the largest values observed during the heart of the monsoon season in July and August...

June, July coincides with the sowing season for crops and the quantum of rain received in this phase determines the fortunes of Indias agriculture and hence about 1/3rd of Indias economy and GDP as well. Delays, less than adequate rainfall can lead to catastrophic effects to farmers who are dependent on the rainfall for his crops. Unseasonal rains can also cause similar effects.

Traditionally about 2/5ths (steadily decreasing) of Indias GDP comes from the agrarian sector,
this is probably the single biggest dependency on nature on a regular basis for any economy.

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