Q. Which of the following influences the weather in winter season in India?
1.Surface pressure and winds
2.Jet streams
3.Tropical cyclones
Choose the correct answer from the given codes:

[A] 1 only

[B] 1 and 2 only

[C] 1 and 3 only

[D] 1, 2 and 3

Answer: D

Explanation: In winter months, the weather conditions over India are generally influenced by the distribution of pressure in Central and Western Asia. A high pressure centre in the region lying to the north of the Himalayas develops during winter.

  • This centre of high pressure gives rise to the flow of air at the low level from the north towards the Indian subcontinent, south of the mountain range.
  • The surface winds blowing out of the high-pressure centre over Central Asia reach India in the form of a dry continental air mass.
  • These continental winds come in contact with trade winds over northwestern India. The pattern of air circulation discussed above is witnessed only at the lower level of the atmosphere near the surface of the earth.
  • Higher up in the lower troposphere, about three km above the surface of the earth, a different pattern of air circulation is observed.
  • The variations in the atmospheric pressure closer to the surface of the earth have no role to play in the making of upper air circulation.
  • All of Western and Central Asia remains under the influence of westerly winds along the altitude of 9-13 km from west to east.
  • These winds blow across the Asian continent at latitudes north of the Himalayas roughly parallel to the Tibetan highlands. These are known as jet streams.
  • Tropical cyclones originate over the Bay of Bengal and the Indian ocean. These tropical cyclones have very high wind velocity and heavy rainfall and hit the Tamil Nadu, Andhra Pradesh and Odisha coast.
  • Most of these cyclones are very destructive due to high wind velocity and torrential rain that accompanies it.

Source: NCERT – Fundamental of Physical Geography