Attenuation in weather radar is defined as what?

• A. It is the absorption of signals by solar radiation.
• B. It is the loss of signal as it propagates through heavy precipitation, reducing detected reflectivity with distance or beyond heavy rain.
• C. It is the scattering of radar waves by small atmospheric particles causing noise.
• D. It is a calibration offset that needs correction.

Answer: (B)

Attenuation is the loss of radar energy as the pulse travels through the atmosphere, especially when it encounters heavy precipitation. In heavy rain, droplets absorb and scatter part of the radar energy, so the return signal from distant rain is weaker. This causes detected reflectivity to drop with distance or beyond the heavy rain. This definition lines up with how attenuation affects radar measurements in real storms. The other ideas don’t describe the propagation loss through precipitation: solar absorption isn’t the mechanism for weather radar, scattering by small particles that creates noise describes clutter, and a calibration offset is a separate instrument correction rather than a propagation effect.