What weather radar technology uses the Doppler effect to measure wind motion?

Doppler weather radar uses the Doppler effect to measure the motion of precipitation and estimate wind movement. It sends radio waves into the atmosphere and analyzes how returning signals change in frequency.

Raindrops, hailstones, and other particles reflect radar energy back toward the antenna. If those particles move toward the radar, the returned frequency shifts one way; if they move away, it shifts the other way. The amount of shift provides radial velocity, meaning motion toward or away from the radar rather than the complete three-dimensional wind vector.

Modern systems combine reflectivity, which shows the strength of returned echoes, with velocity data. Forecasters use these displays to identify rotating thunderstorms, squall lines, intense rainfall, hail, and possible tornado signatures. Dual-polarization radar can also provide clues about the shape and type of particles.

Doppler radar does not directly photograph clouds or measure every wind direction. Mountains, Earth’s curvature, distance, and the radar beam’s height can all limit what it detects.