Numerical simulations of the July 10, 1996, Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO)-Deep Convection experimentstorm: Redistribution of soluble tracers

By using a three-dimensional convective cloud model to simulate the July 10 , 1996, Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozo ne-Deep Convection experiment storm, we investigate the fate of tracers of varying solubilities in midlatitude convection. The tracer distribution res ulting from the interactions of tl;e soluble tracers with the cloud hydrome teors is illustrated for two cases. The first case assumes that the dissolv ed tracer in the cloud water or rain completely degasses when the parent hy drometeor is converted to ice, snow, or hail through microphysical processe s. The second case assumes that the dissolved tracer is retained in the ice , snow, or hail. We find that when soluble tracers are degassed, both low- and high-solubility tracers are transported to the upper troposphere. When tracers are retained in ice hydrometeors, the highly soluble tracers are no t ultimately transported to the upper troposphere but, instead, are precipi tated out of the upper troposphere by snow and hail. Tracers of low solubil ity are transported upward, similar to passive tracer transport. The key mi crophysical processes that control these results are the accretion of cloud water by snow and hail. For the simulation in which retention of tracers i n ice was considered, highly soluble scalars (10(5) M atm(-1)) have a scave nging efficiency > 55% and have a mass change in the upper troposphere (8-1 5 km mean sea level) of -0.5 x 10(5) kg to 0 for a 3-hour period, while a p assive scalar has a mass change of 2.3 x 10(5) kg.