Differential reflectivity Z_DR is used to estimate which aspect of precipitation?

Differential reflectivity Z_DR is used to estimate which aspect of precipitation?

• A. Drop sizes.
• B. Wind speed.
• C. Drop shapes and sizes.
• D. Temperature.

Answer: (C)

Differential reflectivity compares how a radar echo differs between horizontal and vertical polarizations. Because raindrops are not perfect spheres and become more oblate as they grow, the horizontal beam encounters a larger cross-section than the vertical beam, producing a stronger horizontal return and a positive Z_DR. The larger the drop, the more flattened it tends to be, so Z_DR also carries information related to drop size (distribution). Temperature and wind speed aren’t directly inferred from Z_DR. So this parameter is used to infer drop shapes and, to some extent, their sizes.

Differential reflectivity compares how a radar echo differs between horizontal and vertical polarizations. Because raindrops are not perfect spheres and become more oblate as they grow, the horizontal beam encounters a larger cross-section than the vertical beam, producing a stronger horizontal return and a positive Z_DR. The larger the drop, the more flattened it tends to be, so Z_DR also carries information related to drop size (distribution). Temperature and wind speed aren’t directly inferred from Z_DR. So this parameter is used to infer drop shapes and, to some extent, their sizes.