Scale dependency of variances and fluxes in large-eddy simulations of convection during HI-SCALE

Description

Better understanding of scale-dependency of variances and co-variances (fluxes) of dynamical and thermodynamical variables is critical for improving climate model representations of atmospheric boundary layer (ABL) processes at gray zone resolutions, where part of the horizontal variability is resolved and part is parameterized. In this study, we examine how the partitioning of the variances into resolved and sub-grid scale components changes with progressively coarsened horizontal grid. High-resolution simulations of convective boundary layer case from the Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) field campaign are taken from the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) project and a separate set of WRF runs using a more realistic setup. By comparing semi-idealized LASSO simulations with WRF-LES, performed using a larger horizontal domain and spatially variable land surface characteristics, we explore how the scaling properties of the variances depend on land-atmosphere interactions and mesoscale variability. Implications for parameterizations in coarse-resolution models are also discussed.