What is the significance of Westerly Jet Streams in winter?

The correct answer is Guide Western Disturbances into India.

Key Points

• Westerly Jet Streams are fast-moving air currents in the upper atmosphere that significantly influence weather patterns during winter.
• These jet streams play a key role in guiding Western Disturbances, which are extratropical storms originating in the Mediterranean region, into the Indian subcontinent.
• Western Disturbances bring rainfall and snowfall to northern and northwestern India during winter, particularly in the states of Jammu & Kashmir, Himachal Pradesh, and Uttarakhand.
• The Westerly Jet Streams are strongest during winter months due to the temperature gradient between the tropics and polar regions.
• These jet streams significantly influence agricultural activities in India, as the precipitation from Western Disturbances supports Rabi crops like wheat and barley.

Additional Information

• Western Disturbances:
  • Western Disturbances are weather systems characterized by low-pressure areas and are carried into India by Westerly Jet Streams.
  • They originate over the Mediterranean Sea, Caspian Sea, and Black Sea regions.
  • These disturbances cause rainfall and snowfall in the Himalayan region during winter months.
  • They are crucial for maintaining the winter crop cycle in northern India.
• Jet Streams:
  • Jet streams are narrow bands of strong winds in the upper levels of the atmosphere.
  • They are typically found at altitudes of 9-12 km above the Earth's surface.
  • Jet streams are caused by the temperature contrast between tropical and polar regions.
  • The two major jet streams influencing India are the Westerly Jet Stream (winter) and the Easterly Jet Stream (summer).
• Impact on Indian Climate:
  • In winter, Westerly Jet Streams guide Western Disturbances, causing rainfall over northwestern India and the Himalayas.
  • In summer, the Easterly Jet Streams contribute to the onset of the Indian monsoon.
  • Jet streams significantly affect the distribution and intensity of rainfall in India.
  • They also influence temperature patterns and seasonal shifts in weather systems.
• Rabi Crops:
  • Rabi crops are winter crops sown in October-November and harvested in March-April.
  • Wheat, barley, mustard, and peas are examples of Rabi crops.
  • Rainfall from Western Disturbances during winter is essential for their cultivation.
  • Regions dependent on Rabi crops are particularly affected by variations in Westerly Jet Streams.