Characterizing land-atmosphere coupling and the implications for subsurface thermodynamics

The objective of this work is to develop a Simple Land-Interface Model (SLIM) that captures the seasonal and interannual behavior of land-atmosphere coupling, as well as the subsequent subsurface temperature evolution. The model employs the one-dimensional thermal diffusion equation driven by a surface flux boundary condition. While the underlying physics is straightforward, the SLIM framework allows a qualitative understanding of the first-order controls that govern the seasonal coupling between the land and atmosphere by implicitly representing the dominant processes at the land surface. The model is used to perform a suite of experiments that demonstrate how changes in surface air temperature and coupling conditions control subsurface temperature evolution. The work presented here suggests that a collective approach employing both complex and simple models, when joined with analyses of observational data, has the potential to increase understanding of land-atmosphere coupling and the subsequent evolution of subsurface temperatures.