Wednesday, 17 January 2007: 2:00 PM
The Sensitivity of PBL Parameterizations Modeled by MM5 to Various Surface and Boundary Layer Parameters and their Impact on a Unique Satellite Data Assimilation Technique
212B (Henry B. Gonzalez Convention Center)
Land surface forcing is the driving force in the development of the planetary boundary layer and its subsequent circulations. Satellite data assimilation provides the numerical weather prediction community with a means to include high spatial resolution land surface information in numerical simulations. A technique has been developed for assimilating GOES-derived skin temperature tendencies into the surface energy budget equation of the MM5 so that the simulated rate of temperature change closely agrees with the satellite observations. This technique has shown promise in improving numerical simulations, however, with any land surface data assimilation technique, critical assumptions must be made to account for difficult to measure parameters. In order to better understand the limitations of the technique, the sensitivity of various PBL parameterizations modeled by the MM5 to changes in surface and boundary layer parameters including roughness length, albedo, heat capacity, moisture availability, and increases in vertical resolution within the boundary layer are examined. Of key interest are the impacts of these changes to the surface skin temperature, the partitioning of sensible and latent heat flux, the downward longwave radiation, and boundary layer height.