Wednesday, 1 August 2001
Profiler Observations of Boundary Layer Convergence Zones
Data from the UAH Mobile Integrated Profiling System (MIPS) are used in conjunction with proximity Doppler radar and GOES satellite data to characterize the properties of mesoscale convergence zones, including gust fronts, convergence initiated by solenoidal circulations and gravity waves. The MIPS data consist of a 915 MHz profiler, a 2 kHz Doppler sodar, RASS, a lidar ceilometer and surface measurements. The paper presents data collected during the Texas Air Quality Studies experiment (TexAQS), conducted during August-September 2000 around the Houston area. Several boundaries were observed during this period: (a) a vigorous gust front, (b) small-scale boundaries generated by apparent local differential surface heat flux, (d) inland extensions of convergence zones produced by merger of the Gulf and Galveston Bay sea breeze circulations, a nocturnal convergence zone of unknown classification. In some cases, these convergence zones initiated vigorous deep convection. The MIPS data are merged and related to WSR-88D (Z, Vr) and GOES VIS data to characterize, at high temporal and vertical resolution (profiler - 60 s, sodar - 20 s and ceilometer - 15 s), vertical profiles of vertical motion, horizontal winds, cloud bases, elevated aerosol loading, and changes in the boundary layer parameters such as depth and turbulence, within the convergent zone. These data are merged to relate the MIPS measurements of cloud, Z and Vr patterns associated with the CV.