Meteorologists frequently study precipitation events using radar imagery generated at both ground level and from satellite data. Radar sends out electromagnetic waves that bounce off ice or water droplets suspended in the air. These waves quickly return to the radar site in a process called backscattering. Scientists have observed that backscattering reaches its peak during the melting process as water falls through the atmosphere. High backscattering typically results in warm color returns on a radar displays, indicating heavy precipitation.
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Source: Phys.org