Subject: Physical Geography

The troposphere, the lowermost layer of Earth's atmosphere extending up to about 8-18 km, plays a crucial role in determining weather processes through various mechanisms and characteristics.

Characteristics Making Troposphere Weather-Significant

• Temperature Profile:

  • The layer exhibits negative lapse rate (temperature decreases with height at 6.5°C/km).
  • This creates unstable conditions promoting vertical mixing and formation of clouds and precipitation.

• Water Vapor Concentration:

  • Contains 90% of atmospheric water vapor.
  • Facilitates formation of different types of clouds, precipitation, and atmospheric circulation patterns.
  • According to INSAT-3D data, Upper Tropospheric Humidity (UTH) measurements help in weather forecasting and monitoring.

Weather Processes in Troposphere

• Convection and Mixing:

  • Vertical movement of air creates atmospheric instability.
  • Results in formation of thunderstorms, cyclones, and other weather phenomena.
  • Recent data shows India experienced extreme weather events on 235 out of 273 days (86%) in 2023.

• Heat and Energy Transfer:

  • Outgoing Longwave Radiation (OLR) measurements by INSAT-3D/3R satellites help monitor temperature variations.
  • Land-atmosphere interactions influence local and regional weather patterns.

Dynamic Nature and Climate Change Impact

• Tropopause Height Changes:
  • ERA5 reanalysis data (1980-2021) shows tropical tropopause height increasing by 0.06 ± 0.01 km/decade.
  • Temperature trends showing warming of 0.10 ± 0.11 K/decade (2006-2021) affect weather patterns.

The troposphere's significance in weather processes is evident from recent extreme weather events in India, causing 2,923 deaths and affecting 1.84 million hectares of crop area in 2023. Modern meteorological tools like INSAT satellites provide crucial data for understanding and predicting these weather phenomena, making troposphere monitoring essential for weather forecasting and climate change studies.