South-west Monsoons
No Comments
South-west Monsoons
Subject – Geography
Context – Private weather forecaster Skymet Weather Services Private Limited has downgraded its forecast for the South-West Monsoon this year.
Concept –
- The climate of India is described as the ‘monsoon’ In Asia, this type of climate is found mainly in the south and the southeast.
- Out of a total of 4 seasonal divisions of India, monsoon occupies 2 divisions, namely:
- The southwest monsoon season– Rainfall received from the southwest monsoons is seasonal in character, which occurs between June and September.
- The retreating monsoon season– The months of October and November are known for retreating monsoons.
- Factors Influencing South-West Monsoon Formation:
- The differential heating and cooling of land and water creates a low pressure on the landmass of India while the seas around experience comparatively high pressure.
- The shift of the position of Inter Tropical Convergence Zone (ITCZ)in summer, over the Ganga plain (this is the equatorial trough normally positioned about 5°N of the equator. It is also known as the monsoon-trough during the monsoon season).
- The presence of the high-pressure area, east of Madagascar, approximately at 20°S over the Indian Ocean. The intensity and position of this high-pressure area affect the Indian Monsoon.
- The Tibetan plateau gets intensely heated during summer, which results in strong vertical air currents and the formation of low pressure over the plateau at about 9 km above sea level.
- The movement of the westerly jet stream to the north of the Himalayas and the presence of the tropical easterly jet stream over the Indian peninsula during summer.
- Tropical Easterly Jet(African Easterly Jet).
- El Nino/Southern Oscillation (SO):Normally when the tropical eastern south Pacific Ocean experiences high pressure, the tropical eastern Indian Ocean experiences low pressure. But in certain years, there is a reversal in the pressure conditions and the eastern Pacific has lower pressure in comparison to the eastern Indian Ocean. This periodic change in pressure conditions is known as the SO.
