Exploring the Dependence of MYNN PBL Scheme on Dynamic Cores (ARW and FV3) in Simulating Marine Boundary Layer Clouds

Tropical shallow-cumulus clouds, which are the most abundant cloud on Earth, have a notable impact on Earth’s shortwave radiation budget. To precisely model cloud feedback in weather models, it is imperative to accurately represent marine tropical shallow cumulus as well as organized forms of shallow cumuli. Towards a unified planetary boundary layer (PBL) scheme that can effectively operate when coupled with various dynamic cores (dycores), our research delves into the sensitivity of Mellor-Yamada-Nakanishi-Niino (MYNN) Eddy diffusivity-Mass Flux (EDMF) scheme to different dycores and explore the sensitivities in dynamic and thermodynamic aspects. Specifically, this study assesses the impacts of two different dycores on simulated marine boundary layer (MBL) structure and marine clouds morphology using MYNN-EDMF PBL scheme. Simulations are conducted using the Weather Research & Forecasting (WRF) Model with Advanced Research WRF (ARW) dycore and the Unified Forecast System (UFS) Short-Range-Weather (SRW) application with Finite-Volume Cubed-Sphere (FV3) dycore. A regional domain near Barbados with operational horizontal resolutions was set up covering the region where the Elucidating the Role of Cloud-Circulation Coupling in Climate (EUREC4A) field campaign took place in Jan-Feb 2020. Simulated MBL vertical profiles are examined using drop sondes launched from aircraft. Cloud morphologies simulated in the two models are compared with satellite products. The probability density functions (PDFs) of the simulated cloud liquid water path (LWP) derived from the two model simulations are compared with cloud retrievals obtained from GOES-16.