Thermal theory and Air mass theory failed to explain the sudden outburst of Monsoon in India. Jet Stream is given by the West. Jet Stream's theory is able to explain the sudden outburst of the monsoon but failed to explain the complete mechanism and rainfall pattern of the Indian monsoon.
Jet Stream:
The jet stream is fast-moving air ranging from 150 kph to 400 kph in speed and might be 1000 kilometers wide in the upper troposphere at around 12 km altitude.
There is three Jet stream in each hemisphere:
- Polar jetstream
- Westerly Subtropical Jet stream
- Easterly Tropical Jet stream
Westerly Subtropical Jet Stream:
Tibetan Plateau bifurcates Jet stream into two major parts;
- First, flow north of the Himalayas
- Second, flow south of the Himalayas
The subtropical Westerly Jet stream that flows over the south of Himlayay is responsible for the onset and withdrawal of the Indian Monsoon.
During winter:
The westerly Jet stream is responsible for western cyclonic disturbance and brings rainfall from the Mediterranean sea to the Indian continents and it is a boon for wheat crops. An increase in night temperature in the winter season indicated the arrival of western disturbance rainfall
During Summer:
- Sun overhead over the tropic of cancer and due to intense heating and presence of ITCZ near 20 to 25 degrees north latitude.
- Due to the presence of ITCZ and intense heating, the southern branch of the Jet stream gradually pushed northward and the ridge developed. At the surface, a low-pressure belt with cyclonic conditions occurs that helps to the sudden outburst of the Monsoon.
- The onset of the Monsoon is the starting point of the northern movement of the Subtropical Westerly Jet stream.
- The advancing of the monsoon in India is followed by the northern movement of the subtropical western jetstream.
- A full-fledged monsoon is experienced in India only after the Southern western Jet Stream moved north of the Tibetan plateau.
- Easterly Jet stream developed after the Heating of the Tibetan Plateau over southern India and it leads to tropical depression in India that helps to the distribution of monsoon in India.
- Discuss the major characteristics of the Indian monsoon with special emphasis on the causative factors( UPSC 1922)
- Discuss the recent theories put forward to explain the origin and mechanism of the Indian Monsoon. ( UPSC, 1994)
- Elucidate the mechanism of the Indian Monsoon( UPSC, 1999)
- Explain the Origin, Mechanism, and characteristics of the Summer Monsoon in India. ( UPSC 2002)
- Give a Critical account of the recent theories of the origin of the Indian monsoon with special reference to the Jet Stream Theory. (UPSC, 2006)
- Discuss the mechanism and origin of Monsoon winds and explain the role of El Nino on Monsoon circulation. ( UPSC, 2008)
- Discuss the mechanism of the Indian Monsoon (UPSC 2013)
- Discuss the nature and origin of the Indian monsoon and recent techniques for its prediction. ( UPSC, 2014)
- Give a reasonable account of the Unusual Pattern of Distribution of Monsoonal rainfall in India. ( UPSC, 2017)
- Why is the monsoon erratic in nature? Explain. ( UPSC 2019)
- Explain the origin, progress, and retreat of the Indian monsoon and discuss its impact on the Indian economy. (UPSC 2018, 250 words, 20 marks)
- Elaborate on the origin of monsoon with reference to thermal and recent concepts. ( UPPSC 2020)
- Origin and Mechanism of Indian Monsoon
- Rainfall Pattern of Indian Monsoon
- Jet stream theory of Monsoon
- Characteristics or Nature of Indian monsoon
- Air Mass Theory of Monsoon or ITCZ theory
- Thermal theory of monsoon by Halley
- El Nino | La Nina |SO| ENSO| IOD-Indian Ocean Dipole
- Elaborate on the origin of monsoon with reference to thermal and recent concepts.
- Recent Theory of Origin and Mechanism of Monsoon
ConversionConversion EmoticonEmoticon