Climate impacts of parameterizing subgrid variation and partitioning of land surface heat fluxes to the atmosphere with the NCAR CESM1.2

Abstract. All current global climate models (GCMs) utilize only grid-averaged surface heat fluxes to drive the atmosphere, and thus their subgrid horizontal variations partitioning are absent. This can result in many simulation biases. To address this shortcoming, a novel parameterization scheme considering of sensible latent atmosphere associated is developed implemented into National Center for Atmospheric Research (NCAR) Climate Earth System Model 1.2 (CESM1.2). Compared default model, addition improved boreal summer precipitation over eastern China coastal areas Bay Bengal, long-standing overestimations on southern margins Tibetan Plateau (TP) most GCMs alleviated. The margin TP from suppressed large-scale precipitation, while that edge due decreased convective precipitation. Moisture advection blocked toward TP, anomaly anticyclonic moisture transport northern extends westward, suppressing local convection TP. altered circulation lower resulting anomalous heating cooling planetary boundary layer responsible change transport. performance other key variables (e.g., energy fluxes, clouds 2 m temperature) also evaluated thoroughly using CESM1.2, new stochastically allocating (i.e., without included). study highlights importance simulating hydrological cycles GCMs.