What is Doppler radar used for in weather applications?

• A. To measure precipitation size.
• B. To measure reflectivity only.
• C. To measure radial velocity of precipitation, aiding wind pattern analysis and clutter reduction.
• D. To determine air quality.

Answer: (C)

Doppler radar in weather is used to measure how fast precipitation is moving toward or away from the radar along the line of sight, using the Doppler frequency shift of the returned signal. This radial velocity information lets meteorologists map wind patterns inside storms, identify rotation and shear, and track evolving storm dynamics that can indicate severe weather. It also helps reduce clutter because stationary objects like buildings or terrain have little or zero radial velocity and can be distinguished from moving weather targets. While Doppler radar does provide reflectivity data to gauge precipitation intensity, the defining advantage is the velocity information it adds, not precipitation size. Air quality is not determined by this radar type, as that relies on different sensors and methods.