6.6
Profiler observations of squall lines and linear convective systems
Kevin R. Knupp, Univ. of Alabama, Huntsville, AL; and J. Walters
This paper summarizes a collection of observations of the near environment and structure of squall lines observed during the winter and spring months over northern Alabama. The observations are derived from the UAH Mobile Integrated Profiling System (MIPS) supported with single Doppler radar observations and meso-gamma-scale surface network observations around the MIPS site. MIPS components include a 915 MHz Doppler profiler, a 2 kHz Doppler sodar and a lidar ceilometer. This paper will focus on the spatial/temporal variation of the boundary layer wind, low level stability and cloud base properties in advance of convective lines, using combined high resolution wind profiles from the 915 MHz radar and sodar, a radio acoustic sounding system and the ceilometer. Very high-resolution wind profiles are obtained within the lowest 2-3 km, and virtual temperature profiles up to 600-1000 m AGL. These data will define the small-scale nature of jets immediately in advance of squall lines, and relate the horizontal and vertical shears to the severity of the line. In two cases to date, short-lived tornadoes formed within several km of the MIPS site. These data will be used to define the source region of air feeding the convective-scale updrafts, and the horizontal and vertical vorticity of this inflow air. A secondary objective is to define the kinematics of the convective and stratiform regions of squall lines to determine the range of structures that exist. We are particularly interested in examining the behavior of cloud base in the trailing stratiform region of squall lines.
Session 6, Mesoscale Convective Systems II
Wednesday, 13 September 2000, 10:30 AM-12:00 PM
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