Grid Spacing Sensitivities of Simulated Mid‐Latitude and Tropical Mesoscale Convective Systems in the Convective Gray Zone.
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| Title: | Grid Spacing Sensitivities of Simulated Mid‐Latitude and Tropical Mesoscale Convective Systems in the Convective Gray Zone. |
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| Authors: | Ramos‐Valle, A. N.1 (AUTHOR) aramos@ucar.edu, Prein, A. F.1 (AUTHOR), Ge, M.1 (AUTHOR), Wang, D.2 (AUTHOR), Giangrande, S. E.2 (AUTHOR) |
| Source: | Journal of Geophysical Research. Atmospheres. 5/27/2023, Vol. 128 Issue 10, p1-16. 16p. |
| Subject Terms: | *Weather forecasting, Mesoscale convective complexes, Atmospheric radiation measurement, Fronts (Meteorology), Meteorological research |
| Geographic Terms: | Manaus (Brazil), Oklahoma, Great Plains |
| Abstract: | The main objective of this study is to observationally constrain processes in tropical and midlatitude mesoscale convective systems (MCSs), and to use these constraints for model evaluation. To accomplish this, we leverage MCS observations collected at the U.S. DOE Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in Oklahoma and ARM's mobile GoAmazon2014/15 site in Manaus, Brazil (MAO). We simulate 13 and 11 of these observed MCSs at the SGP and MAO site, respectively, using the Weather Research and Forecasting model at 12‐, 4‐, 2‐, and 1‐km horizontal grid spacing. Observations from radiosondes, surface meteorology, and radar wind profilers are used to characterize MCS properties, such as MCS timing and location, cold pools, and convective drafts, and evaluate these simulations. SGP cases are found in better agreement with observations than MAO cases, and when simulated at 2 km, outperform simulations at 1 km regarding the timing of MCS overpass and the accuracy of surface variable trends. MAO simulations suggest a consistent improvement in model accuracy with increasing model resolution in depicting the downdraft structure, the timing of MCSs, and the surface variables changes, except for the latter two metrics at 2 km. Deficiencies are still evident at km‐scales, suggesting the need for higher resolution to simulate tropical MCSs. Overall, location‐dependent improvements in MCS representation are obtained with the increasing model resolution, prompting the evaluation of sub‐km scale simulations. Plain Language Summary: Mesoscale convective systems (MCSs) are known for producing damaging winds, heavy rain, and flooding. The main objective of this study is to evaluate simulations of tropical and midlatitude MCSs with the overarching goal of improving MCS simulations. Observations collected at sites in the Southern Great Plains (SGP) in Oklahoma and in Manaus, Brazil (MAO) are used for model evaluation. We simulate 24 observed MCSs at the SGP and MAO sites using the Weather Research and Forecasting (WRF) model at kilometer‐scale horizontal grid spacings. Observations from radiosondes, surface meteorology, and radar wind profilers are used to evaluate these simulations. SGP and MAO simulations suggest an improvement in model accuracy with increasing model resolution. Overall, location‐dependent improvements in MCS representation are obtained. These results will allow for better MCS and related hazard representation in models. Key Points: Improvements of increasing model grid spacing are location‐dependent and generally smaller at the midlatitude site than at the tropicsAt both sites, improvements with increasing grid spacing are not monotonic—generally 2 km simulations partly outperform 1 km simulations [ABSTRACT FROM AUTHOR] |
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| Database: | GreenFILE |
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