Large parts of North India, including Delhi, Punjab, and Uttar Pradesh, have been experiencing heavy fog since December 2023. The India Meteorological Department (IMD) uses maps from the INSAT 3D satellite to provide visibility alerts. These maps utilize solar reflectance and brightness temperature, determined by three wavelengths: 0.5 µm (visible radiation), 1.6 µm (shortwave infrared radiation), and 10.8 µm (thermal infrared radiation). The strength of each signal dictates the RGB colour scheme on the map, aiding in the analysis of cloud types, thunderstorm stages, snow detection, and fire identification. The INSAT 3D satellite’s capabilities offer valuable insights into weather conditions.
Decoding Satellite Maps: How INSAT 3D Reveals Fog in North India
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