A Method for Estimating Rainfall Rate-Radar Reflectivity Relationships

Abstract

Raindrop-size distributions obtained with the drop camera have been used to determine rainfall rate-radar reflectivity relationships for nine different locations throughout the world. Since the climates sampled were quite varied, an extrapolation of these Z-R relationships to other areas of the world with similar ?drop-spectra climates? can be performed. Two climatic parameters, the mean annual per cent of rain days that are thunderstorm days, and the mean annual relative humidity at 0.5 km above ground, were found to be highly correlated with the coefficient A and exponent b in the Z-R equation, Z = ARb. Regression equations based on the two climatic parameters were determined, permitting an estimation of the Z-R relationship for any area once the parameters are obtained.