Towards a Unified Setup to Simulate Mid‐Latitude and Tropical Mesoscale Convective Systems at Kilometer‐Scales

Journal Article · 03 August 2022 · Earth and Space Science

DOI: https://doi.org/10.1029/2022EA002295 · OSTI ID:1879782

Prein, Andreas F.  ^[1]; Ge, Ming ^[1]; Valle, Alexandra Ramos  ^[1]; Wang, Dié  ^[2]; Giangrande, Scott E.  ^[2]

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1. National Center for Atmospheric Research Boulder CO USA
2. Brookhaven National Laboratory Upton NY USA

Abstract Mesoscale convective systems (MCSs) are the main source of precipitation in the tropics and parts of the mid‐latitudes and are responsible for high‐impact weather worldwide. Studies showed that deficiencies in simulating mid‐latitude MCSs in state‐of‐the‐art climate models can be alleviated by kilometer‐scale models. However, whether these models can also improve tropical MCSs and whether we can find model settings that perform well in both regions is understudied. We take advantage of high‐quality MCS observations collected over the Atmospheric Radiation Measurement (ARM) facilities in the US Southern Great Plains (SGP) and the Amazon basin near Manaus (MAO) to evaluate a perturbed physics ensemble of simulated MCSs with 4 km horizontal grid spacing. A new model evaluation method is developed that enables to distinguish biases stemming from spatiotemporal displacements of MCSs from biases in their reflectivity and cloud shield. Amazon MCSs are similarly well simulated across these evaluation metrics than SGP MCSs despite the challenges anticipated from weaker large‐scale forcing in the tropics. Generally, SGP MCSs are more sensitive to the choice of model microphysics, while Amazon cases are more sensitive to the planetary boundary layer (PBL) scheme. Although our tested model physics combinations had strengths and weaknesses, combinations that performed well for SGP simulations result in worse results in the Amazon basin and vice versa. However, we identified model settings that perform well at both locations, which include the Thompson and Morrison microphysics coupled with the Yonsei University (YSU) PBL scheme and the Thompson scheme coupled with the Mellor‐Yamada‐Janjic PBL scheme.

• Research Organization: ARM Data Center; Brookhaven National Laboratory (BNL), Upton, NY (United States); National Center for Atmospheric Research, Boulder, CO (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: National Science Foundation; USDOE; USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Contributing Organization: Argonne National Laboratory (ANL); Brookhaven National Laboratory (BNL); Oak Ridge National Laboratory (ORNL); Pacific Northwest National Laboratory (PNNL)
• Grant/Contract Number: AC02-06CH11357; SC0012704; SC0020050
• OSTI ID: 1879782
• Report Number(s): BNL-223178-2022-JAAM; e2022EA002295
• Journal Information: Earth and Space Science, Journal Name: Earth and Space Science Journal Issue: 8 Vol. 9; ISSN 2333-5084
• Publisher: American Geophysical Union (AGU)Copyright Statement
• Country of Publication: United States
• Language: English