Atmosphere-Land interaction governs the space-time pattern of the soil mositure state which in turn affects land surface processes and the atmospheric circulation. To explore the highly nonlinear soil moisture dynamics, a coupled mesoscale atmospheric and land surface model is employed over the Central Oklahoma area, by "inserting" the ESTAR daily mapping of surface soil moisture data collected during the Southern Great Plains 1997 (SGP97) Hydrology Experiment. The simulations focus on a three-day period from 12 to 14 July when the weather presented a clear sky and relatively weak horizontal winds. The free atmosphere is simulated by the National Center for Atmospheric Research(NCAR)/Pennsylvania State University Mesoscale Modeling system MM5, and the land surface is described by the coupled land surface flux-hydrology model Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS) and the Distributed Runoff Model (DRUM).
This study compares simulated surface meteorological and hydrological variables such as temperature, pressure, wind, mixing ratio, latent heat and sensible heat fluxes, net radiation, and the soil moisture profile. Results indicate that the surface fluxes and land-atmosphere state variables differ over a wide range when comparing those from climatological values of soil moisture with those based on direct insertion. This suggests that remotely sensed soil moisture, even though only within the top 5 cm of the soil, may provide very useful information for evaluating and updating the surface characteristics. It is also indicative of the potential utility of operational assimilation of remotely sensed soil moisture data for improving the simulation of surface hydrological processes and mesoscale meteorology.