Multiple‐Instance Superparameterization: 1. Concept, and Predictability of Precipitation

Journal of Advances in Modeling Earth Systems

卷:11

Mark D. Branson¹  David A. Randall¹  Todd R. Jones² 

[1] Department of Atmospheric Science Colorado State University Fort Collins CO USA;

[2] Department of Meteorology University of Reading Reading UK;

关键词: precipitation;    predictability;    superparameterization;    convection;    critical phenomena;   

DOI  :  10.1029/2019MS001610

来源: DOAJ

【 摘 要 】

Abstract We have investigated the predictability of precipitation using a new configuration of the superparameterized Community Atmosphere Model (SP‐CAM). The new configuration, called the multiple‐instance SP‐CAM, or MP‐CAM, uses the average heating and drying rates from 10 independent two‐dimensional cloud‐permitting models (CPMs) in each grid column of the global model, instead of a single CPM. The 10 CPMs start from slightly different initial conditions and simulate alternative realizations of the convective cloud systems. By analyzing the ensemble of possible realizations, we can study the predictability of the cloud systems and identify the weather regimes and physical mechanisms associated with chaotic convection. We explore alternative methods for quantifying the predictability of precipitation. Our results show that unpredictable precipitation occurs when the simulated atmospheric state is close to critical points as defined by Peters and Neelin (2006, https://doi.org/10.1038/nphys314). The predictability of precipitation is also influenced by the convective available potential energy and the degree of mesoscale organization. It is strongly controlled by the large‐scale circulation. A companion paper compares the global atmospheric circulations simulated by SP‐CAM and MP‐CAM.

【 授权许可】

Unknown