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

2. WSR-88D Characteristics
Data Types:
Reflectivity
Radial Velocity
Spectrum Width
Data Resolution:
Beam Width = 0.93°
Bin resolution = 250m (1km for Reflectivity)
Maximum reflectivity range = 230km
Without unfolding
Maximum unambiguous velocity range = 150km
Less for higher unambiguous velocities

3. WSR-88D 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

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

5. WSR-88D 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 CRAFT
*ldm NSSL
*Z NCDC
*bz2 CAPS
Uncompressed format (8-12 MB per VS)
*ridds all

6. WSR-88D 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.

7. 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

8. Example MDA Output

9. Questions