GRAPES双参数云微物理方案的改进和云降水个例模拟研究：GRAPES_SCM对热带对流云个例的模拟研究

应用全球-区域同化预报系统单柱模式(GRAPES_SCM),对热带暖池国际云试验(TWP-ICE)个例进行数值模拟。通过和实际观测资料进行对比,诊断并改进了Liuma云微物理方案对热带对流云微物理特征的模拟能力。结果显示在GRAPES_SCM框架下,Liuma原方案和WSM6(WRF single moment)方案均能呈现出TWP-ICE期间热带云系的发展特征,并能够明显区分试验期间的季风活跃期和季风抑制期。活跃期Liuma原始方案和WSM6方案模拟的冰云组成结构差异显著,在Liuma原始方案所模拟的冰相水凝物分布中,存在冰雪含量过少、霰过多的现象。改进后的Liuma方案对程序中各微物理过程计算顺序进行了优化,改进后霰质量混合比明显减少,冰雪质量混合比明显增加,冰相水凝物分布较合理。

The Improvement of GRAPES Double Moment Cloud Scheme and Case Study of Cloud Precipitation: Modeling Study of Tropical Convective Cloud via GRAPES_SCM

In this study, the TWP-ICE case is simulated using GRAPES_SCM. By comparing with the observation data, we found that both the Liuma initial scheme and the WRF single moment scheme (WSM6) can well simulated the development of tropical cloud systems during the TWP-ICE. Besides, the active monsoon period and the monsoon suppression period are also reproduced. The results also show that the vertical distribution of ice-phase hydrometeors simulated by the Liuma initial scheme is very different from that simulated by the WSM6 scheme. Compared with the WSM6 scheme, the Liuma initial scheme produces much more graupel but less ice and snow. In the modified Liuma scheme, the order of calculation of the microphysical process is optimized. In the simulation with the modified Liuma scheme, the mixing ratio of graupel becomes smaller while the mixing ratio of ice and snow becomes larger, and surface the precipitation rate is closer to the observation.