An Assessment of Nonhydrostatic and Hydrostatic Dynamical Cores at Seasonal Time Scales in the Energy Exascale Earth System Model (E3SM). (16th February 2022)

• Record Type: Journal Article
• Authors: Liu, W.; Ullrich, P. A.; Guba, O.; Caldwell, P. M.; Keen, N. D.
• Is Part Of: Journal of advances in modeling earth systems. Volume 14:Number 2(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-16
• Subjects: nonhydrostatic effects -- dynamical cores -- resolution -- nonhydrostatic dynamics; Geological modeling -- Periodicals; Climatology -- Periodicals; Geochemical modeling -- Periodicals; 551.5011
• DOI: 10.1029/2021MS002805
• Languages: English
• ISSNs: 1942-2466

Abstract

Abstract: In global atmospheric modeling, the differences between nonhydrostatic (NH) and hydrostatic (H) dynamical cores are negligible in dry simulations when grid spacing is larger than 10 km. However, recent studies suggest that those differences can be significant at far coarser resolution when moisture is included. To better understand how NH and H differences manifest in global fields, we perform and analyze an ensemble of 28 and 13 km seasonal simulations with the NH and H dynamical cores in the Energy Exascale Earth System Model global atmosphere model, where the differences between H and NH configurations are minimized. A set of idealized rising bubble experiments is also conducted to further investigate the differences. Although NH and H differences are not significant in global statistics and zonal averages, significant differences in precipitation amount and patterns are observed in parts of the tropics. The most prominent differences emerge near India and the Western Pacific in the boreal summer, and the central‐southern Indian Ocean and Pacific in the boreal winter. Tropical differences influence surrounding regions through modification of the regional circulation and can propagate to the extratropics, leading to significant temperature and geopotential differences over the middle to high latitudes. While the dry bubble experiments show negligible deviation between H and NH dynamics until grid spacing is below 6.25 km, precipitation amount and vertical velocity are different in the moist case even at 25 km resolution. Plain Language Summary: This paper compares the nonhydrostatic and hydrostatic dynamical cores in the Energy Exascale Earth System Model global atmosphere model. The rainfall difference between the two dynamical cores is noticeable at 28 km resolution, which is much coarser than the conclusions in the traditional studies. The difference maxima are located over the tropical oceans where the moist processes amplify the difference. The difference maxima in summer and winter emerge over different locations indicating season variations. Key Points: Experiments are performed to compare the hydrostatic (H) and nonhydrostatic (NH) dynamic cores in the Simple Cloud‐Resolving Energy Exascale Earth System Model Atmosphere Model Regions with significant differences between H and NH dynamical cores are identified The physical mechanisms driving these differences are investigated