Why the melting layer radar reflectivity is not bright at 94 GHz

At 94 GHz, the highest radar frequency used for atmospheric research, no radar bright band is observed at the melting layer. In this study, simulations of a vertical profile of melting particles and their scattering properties for a variety of melting particle models are used to capture the basic features of the radar reflectivity structure at 94 GHz in the melting layer. Observations of stratiform precipitation from vertically pointing 3 GHz and 94 GHz radars are used for comparison with the model results. The simulations show good agreement with the observations. The melting of precipitating particles results in an abrupt increase in the radar reflectivity at 94 GHz without a subsequent decrease at the base of the melting layer. The simulations also captured a small decrease in the radar reflectivity at 94 GHz (dark band) often observed at the top of the melting layer.