RRM – Climatology when using the CONUS Configuration

Abstract

Static variable resolution atmospheric grids have been shown to be useful in capturing extreme weather and for modeling regional climates in a less computationally expensive as compared to a global high-resolution model.   A variable resolution grid over the Continental United States (CONUS) was chosen to test the physics to be incorporated into the ACME model at ACME’s target atmospheric resolution of 1/4-degrees.   For the CONUS grid, the low-resolution area has a resolution of ne30, or 1-degree, with the high-resolution region being ne120, or 1/4-degree resolution.    Three simulations are compared to better understand the global and CONUS climatologies.   The first simulation is a 5-year pre-industrial simulation using the same tuning parameters as the ACME v0.3 AMIP with the CONUS grid.   The second is an ensemble member of a global high-resolution simulation of ACME v0.3 AMIP.  The third is a global low-resolution simulation again using the same tuning parameters as the ACME v0.3 AMIP.    The magnitudes and spatial patterns of the convective and large-scale precipitation show the CONUS region has similar climatology as an ensemble member of the high-resolution simulation’s similar region.  A developing theory on the cause between high-resolution simulation and the CONUS simulation is due to the improvements in the resolution of the topography.