GRIST单柱模式及其在评估两套物理方案包中的应用

The GRIST single-column model and its application in evaluating two physics parameterization packages

中文关键词:  单柱模式，物理参数化，云和降水过程模拟

英文关键词:Single column model, physical parameterization, cloud and precipitation modeling

中文摘要:

      [目的] 介绍了面向全球-区域一体化预测系统（GRIST）发展的单柱模式（GRIST_SCM）。GRIST_SCM通过将三维大气动力简化为一维计算，实现对大气柱内物理过程的独立测试和评估。基于GRIST_SCM，考察了面向天气预测应用的物理参数化包（PhysW）和面向气候模拟及气候变化预估的物理参数化包（PhysC）在刻画云降水过程时的物理过程间相互作用。[资料和方法] 基于热带暖池国际云试验，展示了两套物理参数化包对一次深对流过程的模拟性能。[结果] PhysW和PhysC都形成了与观测总体一致的云和降水演变趋势。区别在于：PhysC对降水事件生消的捕捉能力弱于PhysW，其原因是深对流触发过于频繁，产生持续弱对流降水；PhysW形成的暖云量少于观测和PhysC，主要原因是深对流对低层水汽的垂直输送较强，使得基于环境相对湿度诊断的大尺度凝结过程以蒸发为主。[结论] GRIST_SCM详细展示了两种物理参数化包对于云降水过程的刻画能力及其差异背后的物理机理。由于PhysW对流参数化能更好地捕捉降水生消过程，因此PhysW表现出比PhysC更好的降水模拟能力，而PhysC模拟的云量分布和云生消过程和观测更为接近，因此展现了优于PhysW的云过程模拟能力。

英文摘要:

      The single-column model of the Global-Regional Integrated forecast SysTem is introduced (GRIST_SCM). GRIST_SCM simplifies the atmospheric dynamics within one atmospheric column and enables relatively independent testing and evaluation for physical parameterizations. Two physics packages, used for weather forecast (PhysW) and climate modeling (PhysC), are tested via GRIST_SCM. The Tropical Warm Pool International Cloud Experiment (TWP-ICE) is used to study the representation of a deep convection process by PhysC and PhysW, respectively. The interactions among physical processes in terms of modeling clouds and precipitation are evaluated. The simulated cloud and precipitation evolution trends in the PhysW and PhysC simulations are overall consistent with observation. PhysW shows a better ability to simulate precipitation processes, while PhysC shows a better ability to simulate cloud processes. PhysC cannot well capture the onset and retreat of rainfall events during TWP-ICE. It produces persistent weak convective precipitation due to the too frequently triggered deep convection. The warm cloud fraction for PhysW is less than the observation and PhysC. This is attributed to the strong vertical transport of low-level water vapor by deep convection process, leading to evaporation dominating in the large-scale condensation/evaporation diagnosis based on relative humidity.