Regional Short-term Climate And Radiation Characteristics Of Cloud-to-case Simulation

Based on the cloud scheme of Chinese Academy Meteorological Sciences (CAMS), an explicit cloud scheme of GRAPES regional model is developed. We perform regional climate for the month of May 2004 and September 2003 with GRAPES regional model including the explicit scheme. To validate the simulated capability of GRAPES regional model, simulated results were compared with observation. We analyze the differences of simulated results between the explicit cloud scheme and warm cloud scheme, such as precipitation, surface temperature, cloud radioactive properties , latent heat and so on. We also have studied the sensitivity of the climate to some microphysical processes including falling speeds of precipitation, auto-conversion of cloud water to precipitation, nucleation of cloud ice and freeze of super-cooled cloud water.As a whole, GRAPES regional model including the explicit cloud scheme is able to reveal the distributions of precipitation, surface temperature, cloudiness and the top-of-atmosphere radiation budget of May 2004 and September 2003. Simulated results show that GRAPES model including the explicit cloud scheme have great capability of simulation.Different microphysical processes and the different spatial and temporal distribution of water species lead to the different simulated results between the explicit cloud scheme and warm cloud scheme. Simulated results of the explicit cloud scheme are better than those of warm cloud scheme. The explicit cloud scheme should be used in simulation of short-term climatic process.Results are different between the sensitivity experiments. We find that nucleation of cloud ice has greatest influence on precipitation and the cloud-drop freezing has least influence on precipitation. Change of one microphysical process has little influence on mean surface temperature, about -0.2 ℃ ~ 0.2 ℃. Falling speeds of precipitation has greatest influence on mean cloud amount and the second is nucleation of cloud ice. Microphysical processes produce significant changes in the vertical distributions of water species. Column water species of middle-level have greatest change in vertical three levels.Microphysical processes also impact on top-of-the-atmosphere radiation budget through influence simulated cloud amounts, column water species and cloud radioactive properties. Falling speeds of precipitation and nucleation of cloud ice have great influence on top-of-the-atmosphere radiation budget.