New Rotation Track Quality Control Techniques for a Multi-Year Climatology

Both the location and intensity of mesocyclone circulations can be monitored in real-time by accumulating regions of high azimuthal shear at low (0-3 km AGL) and mid-levels (3-6 km AGL) over time. These azimuthal shear values are calculated in a noise-tolerant manner by fitting to a plane the Doppler velocity observations in the neighborhood of a pulse volume and then finding the slope of that plane. Non-meteorological signatures caused by poor velocity dealiasing, ground clutter, radar test patterns and spurious shear values often plague rotation tracks created in this manner, however, inhibiting their usefulness.

In order to improve the quality of these fields for real-time use by emergency responders and warning decision-makers, and for an accumulated multi-year climatology as part of the Multi-Year Reanalysis of Remotely Sensed Storms (MYRORSS) project, new quality control measures have been implemented. These measures - new dealiasing strategies, data thresholds, and Multiple Hypothesis Tracking (MHT) techniques - remove nearly all non-meteorological contaminants and successfully isolate the rotation tracks.

Each quality control measure will be discussed and the specific impacts of each will be shown. Storm survey information will be used to compare the resulting rotation tracks to observed tornado damage. Preliminary results of the MYRORSS rotation track climatology will also be presented.