A Two-Column Model Parameterization for Subgrid Surface Heterogeneity Driven Circulations

Earth system models currently struggle to account for the complex effects that land surface heterogeneity can have on land-atmosphere interactions. There have been attempts to include the impact of this heterogeneity on the atmosphere, but they ignore the development of coherent circulations that can be driven by spatial differential surface heating. A wealth of literature, particularly large-eddy simulation (LES) based studies, shows that these circulations have significant impacts on the development and organization of clouds. In this work, we describe a two-column model with a parameterized circulation driven by atmospheric virtual potential temperature profiles, differences in near surface temperature between the two columns, patterns of surface heterogeneity, and the mean background wind. Key aspects of the proposed model structure are compared with LES output, and the model is then implemented between two otherwise independent single column models. While some avenues for improvement exist, when the circulations are parameterized, we see increased cloud development and realistic changes to the mean profiles of temperature and moisture. The proposed model qualitatively matches expectations from the literature and LES, and points to the potential success of its future implementation in coarse grid models. This work addresses the challenge of incorporating land surface heterogeneity into earth system models to better understand land-atmosphere interactions. Current models struggle to account for the complex effects of subgrid land surface heterogeneity on these interactions, especially when a warmer region near a cooler region can cause a circulation to occur. The study proposes a two-column model that includes a parameterized circulation driven by vertical temperature profiles, surface temperature differences, surface heterogeneity patterns, and the background wind. The model is compared to high resolution large-eddy simulation (LES) output for 3 days in the Southern Great Plains. The results show that the model qualitatively reproduces patterns observed in LES and the existing literature, primarily that cloud production increases and concentrates over warmer surface areas. The model's success suggests its potential implementation in coarse grid models to explore regional and global atmospheric impacts of subgrid land surface heterogeneity. Additionally, the similarities between land surface heterogeneity circulations and other thermally driven circulations indicate potential applicability in subgrid-scale parameterization of sea and lake breezes. While limitations and opportunities for improvement exist, overall this work represents a promising step toward understanding the impacts of subgrid heterogeneity on cloud production and atmospheric processes in earth system models. A parameterized circulation between two otherwise independent columns is described and evaluated for three simulation days Large-eddy simulations (LES) show substantial agreement with the overall circulation model structure proposed When implemented, the parameterized circulation yields similar changes in the atmospheric profiles and cloud production to LES