1College of Geosciences and School of Meteorology, The University of Oklahoma - U.S.A.
2 School of Meteorology, Norman, Oklahoma - U.S.A.
In the years 1985 through 1995, the United States deployed a national network of WSR-88D Doppler Weather Surveillance Radars. Following deployment, the WSR-88D radar and its associated algorithms for signal processing and recognition of meteorological phenomena have had a significant positive impact in severe weather forecasting nationwide. The data stream from the radars also provides many opportunities for research. However, prior to about the year 2000, researchers had either to utilize highly filtered, low resolution products from the radars, or access a limited set of high resolution data from a tape archive in a time-consuming process. Beginning in 2000, a demonstration project was begun that provides continuous, real-time access to high-resolution data from a number of WSR-88D radars via the Internet. This provides researchers many opportunities to process radar data in ways different from the operational processing. In particular, it provides opportunities to develop radar-based climatologies of phenomena that are not possible from traditional meteorological observations. These include mesocyclones, hail, and high precipitation rates. To demonstrate the feasibility of such studies, we are attempting to build on previous work by Stumpf et al and accumulate through near-real-time processing of data from six proximate radars the climatology of mesocyclones over Oklahoma and north-central Texas, and to investigate the relationship between this climatology and the distribution of reported tornadoes. This work uses mesocyclone detections made by variants of the Mesocyclone Detection Algorithm (MDA) in the WSR-88D signal process suite and attempts to associate those with ground truth tornado detections provided by the Storm Prediction Center (SPC) to evaluate the usefulness of mesocyclone detections and their associated attributes.
The presentation will describe the objectives of this ongoing research, the methodology, and show preliminary results from two, possibly three years of data. Early results suggest that mesocyclones (and meso-anticyclones) are relatively common, and that the connection between radar-estimated mesocyclone strength and the occurrence of tornadoes is weak. Some the pitfalls encountered in working with high-resolution radar data will also be discussed.