______ are a narrow belt of high altitude (above 12,000 m) westerly winds in the troposphere. Their speed varies from about 110 km/h in summer to about 184 km/h in winter.

The correct answer is Option 1. 

Key Points

• Jet streams are narrow bands of strong high-altitude winds that flow in the upper troposphere and lower stratosphere, typically between 9 to 16 kilometers (5.5 to 10 miles) above the Earth's surface.
• They are characterized by high wind speeds, often exceeding 100 kilometers per hour (60 miles per hour), and have a significant impact on weather patterns.
• The jet streams are predominantly westerly winds, meaning they flow from west to east.
• They are caused by the temperature contrast between the polar regions and the equator.
• The temperature difference creates a pressure gradient, and the Coriolis effect further influences the wind patterns, leading to the formation of jet streams.
• The speed of jet streams can vary depending on the season and location.

Additional Information 

• Whirlwind:
  • A whirlwind is a weather phenomenon characterized by a rotating column of air.
  • Whirlwinds can occur at various scales, from small tornado-like vortices to larger dust devils. 
• Derecho:
  • A derecho is a widespread and long-lived severe weather event characterized by a straight-line windstorm.
  • It typically forms along the leading edge of a rapidly moving thunderstorm complex, known as a squall line
• Hurricane:
  • A hurricane is a large tropical cyclone with organized thunderstorms and sustained winds of at least 119 km/h (74 mph).
  • Hurricanes form over warm ocean waters and are characterized by a well-defined eye at the center, surrounded by a rotating system of rainbands.