Using GIS to Estimate Uplift due to the Balcones Escarpment in Central Texas

The Balcones Escarpment has been studied for its influence on the occurrence of convective activity. The hypothesis was that air flowing perpendicular to the southern edge of the this south-west to north east aligned 600m high topographic feature triggers convection due to the topographically induced vertical motion. The BEEMEX (Balcones Escarpment Environmental Monitoring Experiment) conducted during one day during May 20917, was designed to test this hypothesis. Data collected from surface observation stations supplemented by surface observations made by a team of eight university students and professors driving across the area below the escarpment were incorporated into a GIS system with topography to calculate uplifting regions. The vertical velocity was estimated by assuming the flow is non-divergent and that the surface observations are temporally static during two blocks of time each of 3 hours duration. The goal was to investigate the impact of topographic uplift described by Slade, 1986, Hopper, 2016, and Nielsen et. al, 2016, on mesoscale convection. A composite of establish ground station data and BEEMEX mobile observations were used to generate a gridded field using ArcInfo and calculate the topographically generated portion of the mesoscale vertical motion field.