Case Study of the Daytime Planetary Boundary Layer Modulation in a Desert Mountain Valley

A field project was conducted in a mountain valley to investigate the structure and evolution of the daytime planetary boundary layer (PBL). Data from a mesonetwork of 18 remote automated weather stations and two 924-MHz lower atmospheric profilers were enhanced with special field measurements. Radiosondes were launched 6 times per day at multiple sites for vertical profiling of kinematic and thermodynamic fields. Soil temperature and moisture data were combined with infrared data from aircraft overflights to map variations in the surface thermal features. The data are used in carrying out numerical simulations with the Penn State/NCAR Mesoscale Model (MM5). Daytime modulation of the PBL is investigated with model control runs and sensitivity studies. MM5 simulations using a slab soil model (version 2) will be compared with simulations using a more sophisticated land-surface model (version 3).