What does the 1st Doppler moment measure?

The first Doppler moment, often referred to as the "mean velocity," measures the average radial velocity of the receiving targets, which are typically hydrometeors in the atmosphere. This measurement is weighted by the power return, meaning that areas with stronger returns have a greater influence on the calculated average velocity than those with weaker returns. This characteristic allows for a more accurate representation of the motion of precipitation particles relative to the radar.

The integration of the returned power signals over a period of time leads to this average calculation, effectively giving meteorologists insights into the overall movement of precipitation by accounting for the varying returns due to different sizes and concentrations of hydrometeors. Thus, this aspect is critical in understanding storm dynamics and precipitation movement.