Abstract

Climate simulation with more accurate process-level representation at finer resolutions is a pressing need in order to provide actionable information to policy-makers regarding extreme events in a changing climate. Computational limitation is a major obstacle for building high-resolution (HR, here 0.25oaverage grid spacing at the equator) models (HRM), especially for the Energy Exascale Earth System Model (E3SM). A more affordable path to HRM is to use a global regionally refined model (RRM), which only simulates a portion of the globe at HR while the remaining is at low-resolution (LR, 1o). In this study, we compare the E3SM atmosphere model version 1 (EAMv1) RRM with the HR patch over the contiguous United States (CONUS) to its corresponding globally uniform LR and HR configurations, as well as to observations and reanalysis data. The RRM has a significantly reduced computational cost (by about 90% dependent on the HR patch size) relative to the globally uniform HRM. Over the CONUS, we examine the geographic distributions of important dynamical and physical quantities as well as various aspects of precipitation. Differences between the RRM and HRM are relatively small and mostly statistically insignificant, thus verifying that the RRM mimics both well- and poorly simulated behaviors of the HRM over the CONUS. Further analysis reveals that one particular RRM bias, the summertime warm bias in surface air temperature, shares the same causes as the HRM. Our results provide additional confirmatory evidence that the RRM is an efficient and effective approach for HRM development and hydrologic research.

Presenter Profile

Dr. Qi Tang received his Ph.D. from Department of Earth system science, University of California, Irvine. He works as a research scientist in the Cloud Processes Research and Modeling group at Lawrence Livermore National Laboratory. He is the lead of the regionally refined modeling in the Energy Exascale Earth System Model (E3SM) project. His research interests include climate modeling, stratosphere troposphere exchange, and land-atmosphere coupling.