Question

Which of the following statements accurately describes the Jet Streams ?

• A. Easterly surface winds blowing across the Indian Ocean.
• B. Winds blowing from the Arctic Circle causing frost.
• C. Westerly winds blowing at an altitude of 9 to 13 km north of the Himalayas.
• D. Low-level air flow moving from south to north.

Answer 1

Answer:

C. Westerly winds blowing at an altitude of 9 to 13 km north of the Himalayas.

Jet Streams

Definition and Characteristics

• Jet streams are relatively narrow bands of strong winds that blow in the Earth's atmosphere, typically at altitudes where commercial aircraft fly.

• They are primarily found in the upper troposphere or lower stratosphere.

• These high-speed air currents are a significant factor in weather patterns.

Jet Streams in the Context of the Himalayas

• The text refers to specific jet streams that play a crucial role in the climate of the Indian subcontinent.

• These are identified as westerly winds, meaning they generally blow from west to east.

• They are observed at a high altitude, specifically between 9 to 13 kilometers above the Earth's surface.

• Crucially, their location is described as being north of the Himalayas.

Significance for India's Climate

• The movement and strength of these jet streams have a direct impact on the Indian monsoon.

• The Western Jet Stream (Subtropical Jet Stream): During winter, this jet stream is located south of the Himalayas. Its southward shift is associated with dry and cold weather in North India.

• The Easterly Jet Stream (Tropical Easterly Jet): During the summer monsoon season, the Western Jet Stream shifts north of the Himalayas. Simultaneously, a new jet stream, the Tropical Easterly Jet, forms over peninsular India, blowing from east to west. This easterly jet is crucial for bringing monsoon rains to India.

• The altitude of 9 to 13 km corresponds to the upper troposphere, where these jet streams are most prominent.