Three-Dimensional Large-Scale Cloud Model: Testing the Role of Radiative Heatingand Ice Phase Processes

摘要

A time-dependent, three-dimensional, large-scale cloud model has been developedfor the prediction of cloud cover, cloud liquid/ice water content (LWC/IWC), precipitation, specific humidity and temperature. Partial cloudiness is allowed to form when large-scale relative humidity is less than 100%. Both liquid and ice phases are included in the model. The liquid phase processes consist of evaporation, condensation, autoconversion and precipitation. The ice phase processes include heterogeneous nucleation to generate ice crystals, depositional growth to simulate Bergeron-Findeisen's process, sublimation to deplete ice crystals, and gravitational settling of ice crystals. The radiative transfer parameterization scheme is based on a broadband method and involves the transfer of infrared and solar radiation in clear and cloudy regions. The broadband infrared emissivity, reflectivity, and transmissivity for cirrus clouds, as well as the broadband solar absorption, reflection, and transmission values for low, middle and high clouds are computed based on the cloud LWC and IWC interactively generated by the cloud model. Large amounts of satellite data, including cloud cover climatology derived from the US'.Air