Regionally refined test bed in E3SM atmosphere model version 1 (EAMv1) and applications for high-resolution modelling

Journal Article · 11 June 2019 · Geoscientific Model Development Discussions (Online)

DOI: https://doi.org/10.5194/gmd-12-2679-2019 · OSTI ID:1526680

Tang, Qi  ^[1]; Klein, Stephen A. ^[1]; Xie, Shaocheng ^[1]; Lin, Wuyin ^[2]; Golaz, Jean-Christophe  ^[1]; Roesler, Erika L. ^[3]; Taylor, Mark A.  ^[3]; Rasch, Philip J. ^[4]; Bader, David C. ^[1]; Berg, Larry K. ^[4]; Caldwell, Peter ^[1]; Giangrande, Scott  ^[2]; Neale, Richard ^[5]; Qian, Yun ^[4]; Riihimaki, Laura D. ^[4]; Zender, Charles S.  ^[6]; Zhang, Yuying ^[1]; Zheng, Xue ^[1]

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1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)
3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
5. National Center for Atmospheric Research, Boulder, CO (United States)
6. Univ. of California, Irvine, CA (United States)

Climate simulation with more accurate process-level representation at finer resolutions is a pressing necessity in order to provide actionable information to policy-makers regarding extreme events in a changing climate. Computational limitation is a major obstacle for building, and running high-resolution (HR, here 0.25° average grid spacing at the equator) models (HRM). 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, 1°). In this study, we compare the Energy Exascale Earth System Model (E3SM) atmosphere model version 1 (EAMv1) RRM with the HR mesh 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 (roughly proportional to the HR mesh size) relative to the globally uniform HRM. Over the CONUS, we evaluate the simulation of important dynamical and physical quantities as well as various precipitation measures. Differences between the RRM and HRM over the HR region are predominantly small, demonstrating that the RRM reproduces both well- and poorly simulated behaviours of the HRM over the CONUS. Further analysis based on RRM simulations with the LR vs. HR model parameters reveals that RRM performance is greatly influenced by the different parameter choices used in the LR and HR EAMv1. This is a result of the poor scale-aware behaviour of physical parameterizations, especially for variables influencing sub-grid scale physical processes. RRM can serve as a useful framework to test physics schemes across a range of scales, leading to improved consistency in future E3SM versions. Applying nudging-to-observations techniques within the RRM framework also demonstrates significant advantages over a free-running configuration for use as a testbed, and as such represents an efficient and more robust physics testbed capability. Our conclusions provide additional confirmatory evidence that the RRM is an efficient and effective approach for HRM development and hydrologic research.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
• Grant/Contract Number: SC0012704
• OSTI ID: 1526680
• Alternate ID(s): OSTI ID: 1542742; OSTI ID: 1631697; OSTI ID: 1544808
• Report Number(s): BNL--211795-2019-JAAM
• Journal Information: Geoscientific Model Development Discussions (Online), Journal Name: Geoscientific Model Development Discussions (Online) Journal Issue: 7 Vol. 12; ISSN 1991-962X
• Publisher: Copernicus Publications, EGUCopyright Statement
• Country of Publication: United States
• Language: English