P37     Modeling extreme precipitation over East China with a global variable-resolution modeling framework (MPASv5.2): Impacts of resolution and physics.

Xu, Mingyue, Chun Zhao, Yu Wang and  Meixin Zhang, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China, Jianping Guo, State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China, Zhiyuan Hu, Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, Lanzhou University, Gansu, China, L. Ruby Leung, Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Michael Duda and William Skamarock, National Center for Atmospheric Research

The non-hydrostatic atmospheric Model for Prediction Across Scales (MPAS-A), a global variable-resolution modeling framework, is applied at a range of resolutions from hydrostatic (60 km, 30 km, 16 km) to non-hydrostatic (4 km) scales using regional refinement over East Asia to simulate an extreme precipitation event, triggered by a typical wind shear in the lower layer of Meiyu front during the East Asian summer monsoon, during 25-27 June 2012 over East China. The simulations are evaluated using ground observations and reanalysis data. The simulated distribution and intensity of precipitation are analyzed to investigate the sensitivity to model configuration, resolution, and physics parameterizations. In general, simulations using global uniform-resolution and variable-resolution meshes share similar characteristics of precipitation and wind in the refined region with comparable horizontal resolution. Further experiments at multiple resolutions reveal the significant impacts of horizontal resolution on simulating the distribution and intensity of precipitation and updrafts. More specifically, simulations at coarser resolutions shift the zonal distribution of the rainbelt and produce weaker heavy-precipitation centers that are misplaced relative to the observed locations. In comparison, simulations employing 4 km cell spacing produce more realistic features of precipitation and wind. The difference among experiments in modeling rainbelt features is found mainly due to the difference of simulated wind shear formation and evolution during this event. Sensitivity experiments show that cloud microphysics have significant effects on modeling precipitation at non-hydrostatic scales, but their impacts are negligible compared to that of convective parameterizations for simulations at hydrostatic scales. This study provides the first evidence supporting the use of convection-permitting global variable-resolution simulations for studying and improving forecasting of extreme precipitation over East China, and motivates the need for a more systematic study of heavy precipitation events and impacts of physics parameterizations and topography in the future.