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Abstract Recent advances in computer modeling have spurred the production of several global storm‐resolving models (GSRMs), which explicitly represent atmospheric circulations from convective to global scales. As a result, GSRMs simulate the formation and evolution of tropical cirrus clouds more physically than typical global climate models/general circulation models (GCMs) which use parameterizations to represent deep convection. We analyze the output from nine GSRMs from the DYAMOND initiative, focusing on the second phase of DYAMOND that simulated a period in January–February 2020. This paper is the third in a series investigating tropical cirrus clouds in GSRMs using DYAMOND model output for an intercomparison. In the tropics, models capture the mean outgoing longwave radiation within −5 to 14 W m⁻²of observed climatology, though most models have more convective precipitation over the 40‐day simulation period than observed. While the models represent large‐scale tropical convection with some fidelity, large regional differences in cloud properties and top‐of‐atmosphere radiation fluxes exist. We focus on a region within the Tropical Western Pacific to study the small‐scale features available with the high spatiotemporal resolution of GSRMs. Most models that participated in both phases of DYAMOND capture the seasonal differences between the two phases, yet each model exhibits unique cloud populations that are persistent across seasons. GSRMs even simulate the notoriously difficult‐to‐observe tropical tropopause layer (TTL) cirrus, providing a novel perspective on TTL cirrus even though the models have different cloud characteristics over the short 40‐days simulation. 

Abstract Pervasive cirrus clouds in the upper troposphere and tropical tropopause layer (TTL) influence the climate by altering the top‐of‐atmosphere radiation balance and stratospheric water vapor budget. These cirrus are often associated with deep convection, which global climate models must parameterize and struggle to accurately simulate. By comparing high‐resolution global storm‐resolving models from the Dynamics of the Atmospheric general circulation Modeled On Non‐hydrostatic Domains (DYAMOND) intercomparison that explicitly simulate deep convection to satellite observations, we assess how well these models simulate deep convection, convectively generated cirrus, and deep convective injection of water into the TTL over representative tropical land and ocean regions. The DYAMOND models simulate deep convective precipitation, organization, and cloud structure fairly well over land and ocean regions, but with clear intermodel differences. All models produce frequent overshooting convection whose strongest updrafts humidify the TTL and are its main source of frozen water. Intermodel differences in cloud properties and convective injection exceed differences between land and ocean regions in each model. We argue that, with further improvements, global storm‐resolving models can better represent tropical cirrus and deep convection in present and future climates than coarser‐resolution climate models. To realize this potential, they must use available observations to perfect their ice microphysics and dynamical flow solvers. 

Abstract Cirrus clouds of various thicknesses and radiative characteristics extend over much of the tropics, especially around deep convection. They are difficult to observe due to their high altitude and sometimes small optical depths. They are also difficult to simulate in conventional global climate models, which have coarse grid spacings and simplified parameterizations of deep convection and cirrus formation. We investigate the representation of tropical cirrus in global storm‐resolving models (GSRMs), which have higher spatial resolution and explicit convection and could more accurately represent cirrus cloud processes. This study uses GSRMs from the DYnamics of the Atmospheric general circulation Modeled On Non‐hydrostatic Domains (DYAMOND) project. The aggregate life cycle of tropical cirrus is analyzed using joint albedo and outgoing longwave radiation (OLR) histograms to assess the fidelity of models in capturing the observed cirrus cloud populations over representative tropical ocean and land regions. The proportions of optically thick deep convection, anvils, and cirrus vary across models and are portrayed in the vertical distribution of cloud cover and top‐of‐atmosphere radiative fluxes. Model differences in cirrus populations, likely driven by subgrid processes such as ice microphysics, dominate over regional differences between convectively active tropical land and ocean locations.