Aircraft Microwave Observations and Simulations of Deep Convection from 18 to 183 GHz. Part II: Model Results

Abstract

In Part II of the 29 June 1986 case study, a radiative transfer model is used to simulate the aircraft multichannel microwave brightness temperatures presented in Part I and to study the convective storm structure. Ground-based radar data are used to derive hydrometeor profiles of the storm, based on which the microwave upwelling brightness temperatures are calculated. Various vertical hydrometeor phase profiles and the Marshall and Palmer (M-P) and Sekhon and Srivastava (S-S) ice particle size distributions are experimented in the model. The results are compared with the aircraft radiometric data. The comparison reveals that 1) the M-P distribution well represents the ice particle size distribution, especially in the upper tropospheric portion of the cloud; 2) the S-S distribution appears to better simulate the ice particle size at the lower portion of the cloud, which has a greater effect on the low frequency microwave upwelling brightness temperatures; and 3) in deep convective regions, significant supercooled liquid water (?0.5 g m?3) may be present up to the ?30°C layer, while in less convective areas, frozen hydrometeors are predominant above ?10°C level.