Evaluating the CoMorph-A parametrization using idealized simulations of the two-way coupling between convection and large-scale dynamics
Evaluating the CoMorph-A parametrization using idealized simulations of the two-way coupling between convection and large-scale dynamics
复制标题
使用对流和大规模动力学之间双向耦合的理想化模拟来评估 CoMorph-A 参数化
DOI：
10.1002/qj.4547
复制
发表时间：
2023
影响因子：
8.9
通讯作者：
Daleu C
中科院分区：
文献类型：
--
作者：
Daleu C
我们提出了一种新的方法来测试对流计划与其大尺度环境的相互作用。使用新的气象局对流方案CoMorph‐A和新的气象局-自然环境研究理事会云解析模型（CRM）的单柱模型（SCM）与阻尼重力波衍生的大尺度动力学相耦合。耦合模式被用来研究对流响应的刺激强迫下的相互作用的大尺度动力学的影响。在CoMorph-A中，默认夹带随对流大小的预测而变化，对流大小取决于早期降雨，并探讨了SCM结果对夹带制剂的敏感性。我们证明了使用CoMorph‐A的SCM的行为现在与CRM的行为非常相似。对于单独施加的温度或湿度刺激，SCM调整到一个新的平衡，这是类似于CRM中，但其瞬态对流反应的刺激，以抑制对流显着太快。对于一个刺激的组合，以提高对流，SCM的响应是强于CRM。最后，对流降雨的SCM是相对不敏感的刺激的组合，同时增强和抑制对流，与CRM协议。然而，从非降水状态的SCM恢复是过度延迟的默认夹带配方，但太快时，夹带率固定在一个低的速度，仅代表深对流状态。我们研究了不同强度的水分刺激的反应。这两个模型产生的降水量与柱相对湿度（CRH）的单调增加，以及急剧增加的降水量CRH超过阈值，在观察中看到。虽然这两个模型正确地捕捉到观察到的CRH阈值，观察到的降水CRH关系的差异。例如，在阈值以上，降水随CRH的增加在SCM中比在CRM和观测中更突然。在SCM中使用低夹带率获得类似的行为。
We present a new methodology to test the interactions of convection schemes with their larger scale environment. A single‐column model (SCM) using the new Met Office convection scheme, CoMorph‐A, and the new Met Office–Natural Environment Research Council cloud‐resolving model (CRM) are coupled to damped‐gravity‐wave‐derived large‐scale dynamics. The coupled models are used to investigate convective responses to stimulus forcings under the influence of interactive large‐scale dynamics. Within CoMorph‐A, the default entrainment varies with the prediction of convection size that is dependent on earlier rainfall, and the sensitivity of the SCM results to the entrainment formulation is explored. We demonstrate that the behaviour of the SCM using CoMorph‐A is now very similar to that of the CRM. For temperature or moisture stimulus applied separately, the SCM adjusts to a new equilibrium that is similar to that in the CRM, but its transient convective responses to stimuli acting to suppress convection are markedly too fast. For a combination of stimuli acting to enhance convection, the SCM responses are stronger than in the CRM. Finally, convective rainfall in the SCM is relatively insensitive to a combination of stimuli acting to enhance and suppress convection simultaneously, in agreement with the CRM. However, the SCM recovery from a non‐precipitating state is overly delayed for the default entrainment formulation but is too rapid when the entrainment rate is fixed at a low rate to represent only the deep convective state. We examined the responses to moisture stimuli of different strengths. Both models produce a monotonic increase of precipitation with column relative humidity (CRH) as well as the sharp increase of precipitation as CRH exceeds a threshold, as seen in observations. Though both models correctly capture the observed CRH threshold, differences from the observed precipitation–CRH relationship are noted. For instance, above the threshold the increase of precipitation with CRH is more abrupt in the SCM than in the CRM and observations. A similar behaviour is obtained in the SCM using low entrainment rate.