Empirical relations between size parameters of ice hydrometeor populations and radar reflectivity

There is a tendency for d and c to decrease when radar frequency increases from K-u band (similar to 14 GHz) toWband (similar to 94 GHz). Correlation coefficients between Z(e) and Lambda can be very high (similar to 0.8), especially for lower frequencies. Such correlations are similar to those for empirical relations between reflectivity and ice water content (IWC), which are used in many modeling and remote sensing applications.

Close correspondences of reflectivity to both Lambda and IWC are due to a relatively high correlation between these two microphysical parameters. Expected uncertainties in estimating Lambda from reflectivity could be as high as a factor of 2, although estimates at lower radar frequencies are more robust. Stratifying retrievals by temperature could result in relatively modest improvement of Lambda estimates.