Determination of the Boundary Layer Characteristics in the Tampa Bay Area During the Bay Region Atmospheric Chemistry Experiment (BRACE)

Variability in boundary layer structure is to be expected in a coastal environment. It is necessary to determine the regional structure of the boundary layer to relate the chemical concentrations upwind and downwind of the urban area and to account for differences in the vertical concentration structure. NOAA's Air Resources Laboratory, using the NOAA Twin Otter, made meteorological and chemical measurements during 21 flights in and around the Tampa Bay area as part of the Bay Region Atmospheric Chemistry Experiment (BRACE). One or more vertical profiles were flown during each flight. The profiles were made from approximately 60 to 3000 m (200 to 10,000 ft) MSL, both over land and over the Gulf of Mexico. NOAA's Environmental Technology Laboratory (ETL) deployed three surface-based 915-MHz radar wind profilers equipped with radio acoustic sounding systems (RASS) during the experiment. The wind profiler/RASS systems were installed at Ruskin, Sydney and St Petersburg. The National Weather Service Office in Tampa (NWS/TBW) also released rawinsondes twice daily from the Ruskin site. The measurements of temperature, dew point, potential temperature, wind speed, and wind direction acquired during the aircraft profiles are analyzed and compared with the profiler and sounding data in order to determine the structure of the boundary layer over the Tampa Bay region and the temporal and spatial changes that occurred in that structure during the flights.