Microphysical Retrieval in Hailstorms Using Scattering Simulation Based on in-Situ Aircraft Measurements and Dual Polarimetric Radar Observations

Much work has been done with S-band polarimetric radar observations to determine hydrometeor types based on the observed polarimetric radar data. Specifically, these schemes identify the radar-dominant hydrometeor type in the regions of clouds scanned by the radar based on the values of the polarimetric parameters. In the current research, quantitative backscatter calculations based on the in-situ measurements of hail size distribution are performed to obtain their corresponding radar moments. The hail size distributions were measured with the Hail Spectrometer Probe during research flights of the South Dakota School of Mines and Technology armored T-28. The radar observations are from the S-band polarimetric CSU-CHILL radar. Microphysical parameters in the backscattering simulations, such as ice to water fraction and axis ratio of the particles, are obtained from matching the observed polarimetric radar measurements. In addition to the backscatter simulations, the acoustic signal recorded by microphones in the windshield of the aircraft is analyzed to characterize periods with intense hail impacts. The microphysical retrievals based on the combined radar and in-situ T28 data for the hail vs. non-hail times will be compared. These results improve our ability to compute integral microphysical properties of storm volumes such as hail number and mass concentrations, and hail kinetic energy and kinetic energy flux, based on observed polarimetric radar signatures aloft.