Question

Consider the following statements regarding "Surface Pressure and Winds" in winter:

1. A high-pressure area develops to the south of the Himalayas.

2. Surface winds blow from Central Asia towards India as a dry air stream.

3. These continental winds make contact with trade winds over North-West India.

Which of the statements given above is/are correct?

• A. 1 only
• B. 1 and 3 only
• C. 2 and 3 only
• D. 2 only

Answer 1

Answer:

C. 2 and 3 only

Winter Pressure Systems and Winds over India

• Statement 1: A high-pressure area develops to the south of the Himalayas. This statement is incorrect. During winter, a high-pressure region forms over the landmasses of North-West India and Central Asia. This is due to the intense cooling of the continental landmass. Conversely, the oceans remain relatively warmer, leading to a low-pressure area over them. This pressure gradient drives winds from high pressure to low pressure.
• Statement 2: Surface winds blow from Central Asia towards India as a dry air stream. This statement is correct. The high-pressure system over Central Asia and North-West India pushes cold, dry, and dust-laden winds towards the Indian subcontinent. These winds originate from the landmass and therefore carry very little moisture, resulting in dry weather conditions across most of India during winter.
• Statement 3: These continental winds make contact with trade winds over North-West India. This statement is correct. The dry continental winds blowing from Central Asia interact with the moisture-laden trade winds originating from the Indian Ocean. This convergence zone is located over North-West India. While the primary influence in North India is the dry continental air, the interaction with trade winds can play a role in localized weather phenomena, though the dominant characteristic remains dryness.

Key Factors in Winter Climate:

• Formation of High Pressure: The Siberian High is a dominant high-pressure system during winter, extending its influence over Central Asia and parts of North India.
• Temperature Gradient: Intense cold over landmasses leads to a significant temperature and pressure difference between continents and oceans.
• Wind Direction: Winds generally blow from the land towards the sea (e.g., from Central Asia towards the Indian Ocean).
• Moisture Content: Winds originating from continental interiors are typically dry, leading to clear skies and cold, dry weather in India, except for some coastal areas influenced by trade winds.