The panels below show the first three moments of the Doppler velocity spectrum measured by the radar. This is related to the size and concentration of the water droplets and ice crystals. Warmer colors indicate larger or more numerous particles. Mean Doppler Vertical Velocity in units of meters per second. This is the average speed at which droplets and ice crystals in the radar sample volume are rising or falling above the radar.
Warm colors indicate downward motion.
Spread of the Doppler Spectrum in units of meters per second. It is related primarily to the distribution of particle sizes and the intensity of turbulence. The abrupt melting transition from slowly settling snowflakes to rapidly falling raindrops is apparent at about 2.5 kilometers height in all three moments in this example.