Atmospheric Boundary Identification and Delineation Experiment II (ABIDE-2)

University Of Alabama In Huntsville, Huntsville AL

Investigators

Abstract

Advanced atmospheric profiling and radar systems will disclose convergent boundary zones properties for a variety of atmospheric boundary layer conditions including the unstable convective boundary layer, the stable nocturnal boundary layer, and the transition in between. The principal goal of ABIDE-2 is to examine the physical properties (structure and evolution) of convergent boundary zones in the atmospheric boundary layer, and investigate their impact on the distribution of water vapor, convective initiation, and deep convection. The ABIDE-2 will strive to accomplish the following objectives: 1. Improve understanding of the physics of convergent boundary zones (water vapor enhancements in particular) through detailed, multi-sensor case studies of convergent boundary zones that form and evolve within a wide spectrum of atmospheric conditions. The following three goals will receive emphasis: a. Compare convergent boundary zone properties, and associated convective initiation in the Huntsville region, with convergent boundary zone/convective initiation properties from the great plains and other regions to broaden our understanding of convergent boundary zone and convective initiation properties as a function of atmospheric stratification; b. Investigate changes in convergent boundary zone behavior during the transition period (plus-minus 2 h of sunset) from the unstable convective boundary layer to the stable nocturnal boundary layer; c. Examine convergent boundary zone (and convective initiation) properties within the stable nocturnal boundary layer. 2. Because synthesis of airflow from scanning radars and radar profilers depends on scattering from biological fliers in the atmospheric boundary layer, properties of biological fliers (vertical and horizontal velocity) will be investigated, including the seasonal and diurnal variability of these properties, to assess accuracy of airflow derived from scanning Doppler radars and Doppler wind profilers. These goals will be accomplished using continuous (24/7) measurements from a cluster of atmospheric profiling instruments consisting of a 915 MHz radar profiler, a 12-channel microwave profiling radiometer, a lidar ceilometer, and a Doppler sodar; a C-band dual-polarization Doppler radar; a second sodar; and surface instrumentation. The broader impacts of this research will be derived through the potential of improved forecasts of weather phenomena impacted by convergent boundary zones (e.g., convective initiation, severe storms, and other hazardous weather). In addition, this research will contribute to improved understanding of biological flyers and parameterizations of their flight characteristics, based on Doppler radar and profiler radial velocity measurements.