Analyzing Tornado Debris Signature and Damage Path Characteristics by Integrating Aerial Imagery and Polarimetric Radar Data in GIS

The historic April 27^th tornado outbreak of 2011 produced 62 tornadoes in the state of Alabama, with the one of the strongest being the EF-5 Hackleburg-Tanner tornado.  The UAH Department of Atmospheric Science contracted The Atlantic Group to fly the Hackleburg-Tanner EF-5 tornado track and capture high-resolution swaths of the damage path, as well as the paths for the violent Cullman and Cordova tornadoes. This case study involves detailed analysis of the aerial imagery, including digitizing tree-falls and damage points, and outlining a damage path for the tornado. These analyses are then merged with georeferenced TIFF files (GeoTIFF) of UAH Advanced Radar for Meteorological and Operational Research (ARMOR) polarimetric radar scans of Reflectivity Factor, Radial Velocity, Correlation Coefficient, Differential Reflectivity, and Spectrum Width in order to analyze dual-polarization radar Tornado Debris Signature (TDSs) associated with the Hackleburg-Tanner tornado. An analysis of the TDSs from this tornado allows for the characterization of the effects of debris loading as the tornado passed over different types of terrain. This case study is unique in that some damage cannot be attributed to the EF-5 tornado, but rather to tornadoes from the previous morning system of April 27^th that crossed similar paths.  Additionally, a large gap in damage from Harvest, AL to the Tennessee state line is being investigated to determine the possibility that the Hackleburg-Tanner tornado dissipated before Franklin County TN and another formed along the same path. The combined analysis of aerial imagery and radar data will provide a detailed picture of how the physical damage and radar signatures correlate and the effects of debris loading over different terrain.