Parameterization of Mean Terminal Velocity of Hydrometeors in Convective Clouds

The relationships between mean terminal velocity and volume diameter of different hydrometeors, as well how they change with background aerosol concentrations have been investigated numerical simulations tropical deep convection from the Weather Forecast Research Model (WRF), coupled spectral bin microphysics. results showed a positive correlation either mass-weighted (Vm) or number-weighted (Vn) volume-mean (Dv), coefficient greater than 0.8. number both large small hydrometeors increase enhanced loading, resulting in increased Vm decreased Vn. parameterizations were established under conditions. parameterized was then compared default values used model when fixed shape parameter (gamma distribution) bulk microphysics, which suggests smaller larger Vn parameterizations. Moreover, proposed further applied to Morrison microphysical scheme for simulation convective cloud. Changes mentioned above directly affect sedimentation precipitating such raindrops, snow, graupel, lead (decreased) mass (number) concentration hydrometeors.