Saturday, 13 January 2007
Radar and Surface Measurements of Boundary Layer Convergence Zones
While boundary layer convergence zones (BLCZs), which are areas of low-level convergence of air (at the surface), influence daily weather, their specific effects on wind, temperature, moisture, and thunderstorm formation are not well known. In order to address this problem, BLCZs that occurred in the 2002 IHOP (International H2O Project) field campaign were documented and analyzed using a variety of data sets which consisted of temperature, wind direction and speed, and moisture values from nearby surface stations as well as measurements of Doppler velocity, radar reflectivity, and a new radar-derived field called refractivity, which provided the horizontal distribution of moisture at the surface. The velocity, reflectivity, and refractivity fields came from the S-band Dual Polarization Doppler Radar (S-Pol) and the moisture, temperature, wind direction, and wind speed came from the surface stations: Verles (VERL), Rustytank (RUST), Lincolns (LINC), and Playhouse (PLAY). The objective of this study was to acquire a better characterization of BLCZs by analyzing data from various sources. The preliminary results indicated similarities in the data between radar fields and surface stations, similarities between the four surface stations, and both similarities and difference between cases documented. With a better characterization of BLCZs, environmental events such as changes in temperature, wind, and moisture as well as thunderstorm development may be better forecasted in the future.