The WSR88 D Radar An overview by Thomas

The WSR-88 D Radar An overview by: Thomas Jones December 2, 2002

WSR-88 D Characteristics • Data Types: – Reflectivity – Radial Velocity – Spectrum Width • Data Resolution: – Beam Width = 0. 93° – Bin resolution = 250 m (1 km for Reflectivity) – Maximum reflectivity range = 230 km • Without unfolding – Maximum unambiguous velocity range = 150 km • Less for higher unambiguous velocities

WSR-88 D Operation Modes • 4 Scanning modes currently available: – VCP-11 = 14 elevation / 5 minute volume – VCP-21 = 9 elevation / 6 minute volume – VCP-31&32 = 4 elevation / 10 minute volume • VCP-31 & 32 are “clear-air” scanning strategies designed for non-convective events • VCP-21 is a “precipitation” mode designed for observing stratoform precipitation events • VCP-11 is a “severe weather” mode designed to observe intense convective events

VCP-11 vs. VCP-21 Height (km) VCP-11 Range (km) VCP-21 Range (km)

WSR-88 D Data • Level-II data – Full resolution “base” data • Includes all moments and elevations • No derived products (unlike Level-III) – Compressed formats (1 -2 MB per VS) • • *raw *ldm *Z *bz 2 CRAFT NSSL NCDC CAPS – Uncompressed format (8 -12 MB per VS) • *ridds all

WSR-88 D Data • Data written to file in a binary format – Each VS begins with short header file containing • Radar site • Volume scan number (1 -999) • Begin date and time of VS – This is not the level-II tape header file which contains radar settings • Not available for level-II data recorded using CRAFT method.

Important Algorithms • Storm Cell Identification and Tracking Algorithm (SCIT) – Identifies “Storm-cells” based on 3 -D reflectivity data • Mesocyclone Detection Algorithm (MDA) – Identifies mesocyclone vortices from radial velocity data using a Rankine vortex model • Tornado Detection Algorithm (TDA) – Identifies TVSs base on gate-to-gate shear from radial velocity data

Example MDA Output

Questions