Comparing Radar Tornadic Debris Signature Properties to Damage and Land Classifications

Utilizing dual polarization radar to identify a Tornadic Debris Signature (TDS) helps forecasters confirm a tornado without physical report. Although many studies have been conducted, it is still unclear as to whether or not dual-polarization radar can diagnose exact tornado strength. Supercell events were examined from 2011 through 2019 using NEXRAD data archives of which dual-polarization data were available. When looking at a supercell, high Base Reflectivity (BR), lowered Co-Polar Correlation Coefficient (CC) and near zero Differential Reflectivity (ZDR) values are a good indicator of a tornado debris signature. Comparing these values to EF scale damage surveys conducted by local National weather Service offices bring forth a relationship between tornado strength and polarimetric radar values. Correlations were found between TDS height/width and EF scale damage, suggesting that the degree of damage likely increases the spatial extent of the TDS signature. After analyzing damage paths relative to specific land use and land cover (LULC) classifications, it was determined that TDS height was positively correlated to CC. Scanning for different dual-polarization variables values, such as ZHH, CC, and in some cases, ZDR, lead to a correlation between the TDS and tornado EF scale. Matching the approximate coordinates of the rated tornado damage to the lowest CC value provide positive correlations, suggesting that TDS properties may be helpful in diagnosing tornado strength. Negative and positive correlations were also found between different land classification types and CC values. Forecasters should therefore consider the potential impact of LULC classification on their diagnosis of potential tornado extent and damage using TDS properties.