A cloud-resolving modeling study of diurnal variations of tropical convective and stratiform rainfall
【摘要】：Diurnal variations of convective and stratiform rainfalls over the tropical ocean are investigated on the basis of data from a two-dimensional cloud-resolving simulation. The model is integrated for 40 days to a quasi-equilibrium state with imposed zero zonally uniform vertical velocity, a constant zonal wind, and a constant sea surface temperature of 29°C. The convective rain rate contributes more to the diurnal variation of model domain- mean surface rain rate than the stratiform rain rate does. The calculations of the surface rainfall equation show that more vapor convergence yields higher convective rain rate and that more vapor convergence and more local vapor loss cause higher stratiform rain rate in early morning than in afternoon. Analysis of cloud microphysics budgets reveals that variations in vapor condensation and associated water microphysical processes are responsible for the diurnal variations of both convective and stratiform rain rates.