An empirical investigation of relationships and interactions between the convective planetary boundary layer and the land surface

The convective planetary boundary layer (PBL) integrates land-atmosphere interactions over regional spatial scales and diurnal temporal scales. Previous attempts to infer surface energy and water budgets from observations of the PBL have been constrained by difficulties in monitoring and estimating the processes that control PBL evolution. This research presents an empirical and modeling investigation of land-atmosphere interactions focusing on the utility of remote sensing of the PBL. An energy conservation approach applied to 132 sets of daily PBL and land surface observations from the Atmospheric Radiation Measurement Cloud and Radiation Test Bed in the Southern Great Plains (ARM-SGP) reveals limitations to using energy budget methods to estimate surface fluxes on diurnal time scales. At the same time, statistical analyses demonstrate that observable properties of the PBL are directly related to land surface conditions and a methodology is established to estimate surface fluxes and moisture conditions that does not require detailed land surface models or parameterizations. These relationships vary as a function of surface properties and atmospheric conditions and are examined in detail using a coupled PBL/land-surface model in association with observational data. More importantly, the results from these analyses identify feedbacks in the land-atmosphere system that are not included in current models of the PBL. The feedbacks and relationships also provide insight regarding the link between surface fluxes and PBL structure, and can be used to estimate surface conditions from routine observations of the PBL.; Vertical temperature profiles retrieved from radiances measured by MODIS and AIRS provide information related to PBL structure. However, a comparison of retrieved profiles with radiosonde measurements shows that MODIS does not have sufficient spectral resolution to accurately discern information on temperatures in the PBL. Similarly, AIRS profiles are limited by biases introduced by retrieval algorithms. Despite these limitations, information on PBL structure can be extracted from AIRS retrievals using empirical relationships. The results also demonstrate that surface conditions are strongly correlated with AIRS radiances and that measurements in as few as five bands are able to explain greater than 80 percent of the variance in observed near-surface soil moisture and sensible heat flux.