Doppler radar in weather systems detects wind shear primarily through what signal?

• A. Steady ambient temperature
• B. Abrupt changes in Doppler velocity indicating wind speed gradients
• C. Color of precipitation
• D. Aircraft altitude

Answer: (D)

Doppler radar detects wind shear by picking up abrupt changes in Doppler velocity across nearby sample volumes, which reveal wind speed (and sometimes direction) gradients. Each radar pulse provides a velocity value along the line of sight for each targeted volume. When wind speeds change rapidly over a short distance—in the horizontal, vertical, or both—adjacent areas show different radial velocities. This appears on the radar display as sharp transitions in color or velocity values, signaling wind shear that can affect aircraft performance.

Steady ambient temperature isn’t what the Doppler signal measures, and the color of precipitation or aircraft altitude don’t directly indicate wind speed gradients.