Representation of boundary layer moisture transport in cloud-resolving models

However, how this transport process can be accounted for in cloud-resolving models (CRMs) is not sufficiently clear and has rarely been examined. A typical CRM can resolve the bulk feature of large convection systems but not the small-scale convection and turbulence motions that carry a large portion of the moisture fluxes.

This study uses a large-eddy simulation of a tropical deep-convection system as a benchmark to examine the subgrid-scale (SOS) moisture transport into a cloud system.', It is shown that most of the PBL moisture transport to the cloud layer occurs in the areas under low-level updrafts, with rain, or under cloudy skies, although these PBL regimes may cover only a small fraction of the entire cloud-system domain. To develop SOS parameterizations to represent the spatial distribution of this moisture transport in CRMs, three models are proposed and tested.