Land-atmosphere interaction plays an important role in weather, climate, and global/regional environmental change. Over arid and semiarid regions, land-atmosphere coupling is also crucial, as these regions represent one-third of the global land. Furthermore, as the vegetation evapotranspiration and the closely coupled water-carbon cycle play a minor role in the surface energy balance over arid regions, understanding the interplay of sensible and ground heat fluxes as well as the surface skin temperature would help us to better understand the more general and complicated land-atmosphere interactions over vegetated areas.

In this presentation, we will discuss our recent work on improving the modeling of surface skin temperature diurnal cycle over arid regions by addressing three questions: how robust is the formulation for computing roughness length for heat with respect to different land models and different elevations? how can the sensible heat flux be constrained under stable (atmospheric stratification) conditions in measurements and modeling? and how can the computation of ground heat flux be constrained in land modeling?

Two community land models (Noah and CLM) are used along with in situ measurements at two sites in the western U.S and over Tibet, China. The applicability of our revisions to global modeling will also be addressed. Through this work, we effectively propose a new approach (based on land-atmosphere coupling) to address the challenging issue of measuring and modeling atmospheric turbulence under stable conditions.