Progress toward improved Ground-Based Velocity Track Display (GBVTD) analysis of high-resolution radar data collected in tornadoes

When Ground-Based Velocity Track Display (GBVTD) analysis is applied to mobile radar data collected in tornadoes, a prominent wavenumber-2 component of azimuthal velocity is often realized. It is believed that this wavenumber-2 feature results primarily from translational distortion of the vortex. Determination of the reference frame of the vortex is an additional problem, owing to the directional scanning strategy that is employed during radar data collection. Methods for determining the steadiest frame of reference, and for compensating for the translational distortion, will be presented. The effects of these measures on resultant GBVTD analyses will be examined.

The choice of objective analysis scheme used to interpolate the radar data from polar to Cartesian coordinates is another potential source of error in GBVTD analysis. Several objective analysis schemes will be investigated, and their impacts on the resultant GBVTD analyses presented.