Question

What causes rainfall in the coastal areas of Tamil Nadu at the beginning of winters?
A. South-West monsoon
B. North-Eastern monsoon
C. Temperate Cyclone
D. Local Air circulation

Answer 1

Hint: The Indian monsoon season normally lasts from June to September, with significant parts of western and central India receiving more than 90% of their total annual rainfall during this time, and southern and northwestern India receiving 50% to 75% of their total annual rainfall during this time. Over the country as a whole, monthly totals average 200-300 mm.

Complete answer:
Let us analyze the given options:
Option A) This is not the correct option because Tamil Nadu is dry during the South-West Monsoon due to its location in a rain shadow area. The southwest trade winds, which blow towards the northern hemisphere, bring rain to Tamil Nadu during the monsoon season. The northeast trade winds provide rain to Tamil Nadu throughout the winter months.

Option B) This is the correct option because during the winter, whenever the land is cooler than the sea, a pressure gradient from land to sea is established. The northeast monsoon is caused by winds blowing in a northeasterly direction over the Indian sub-continent toward the Indian Ocean.

Option C) Temperate cyclones form in latitudes of 35 to 65 degrees north of the equator, whereas Tamil Nadu is located at latitudes of less than 20 degrees.

Option D) This option is not correct because close to the equator, local air circulation occurs, but Tamil Nadu is too far away to be influenced.

Therefore the correct option is B.

Note: The northeast monsoon aids in the intensification of the tropical cyclone's rain bands, increasing the likelihood of rainfall intensity of over 100mm in Hainan province and Guangdong's coastal districts.