The role of surface coupling, turbulent mixing, and radiation in modeling a stable boundary layer over Tibetan Plateau

To enhance the understanding of the impact of small-scale processes in the polar climate, this study focuses on the relative role of snow-surface coupling, radiation and turbulent mixing in stable boundary layer over Tibetan Plateau. This is the first attempt to reveal physical processes under stable stratification with WRF-3D model. All cases are characterized by three different stable boundary layer archetypes, namely, a radiative night, an intermittently turbulent night, and a fully turbulent night (all at clear-sky conditions). First a set of WRF configurations that vary in parametrization schemes for the planetary boundary layer, and land surface are evaluated. we find a wide variety in the state of the atmosphere and the surface variables for the selected parameterization schemes after intercomparisons. To understand this variety, we implement the sensitivity runs to examine which physical process is most crucial, using a unique analysis method so-called ‘process diagrams’. The variation between the sensitivity runs display a relative orientation of model sensitivities to variations in each of the governing processes and these can explain the variety of model results obtained in the intercomparison of different parameterization schemes.