DLOC TOPIC 3 LESSON 1
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Product Resolution and Display Range
Product Range Resolution
Returned power, velocity, and spectrum width are assigned at 0.25 km (0.13 nm) range resolution, which is the best possible. These base data are assigned a memory address, or "bin", that corresponds to a range resolution of 0.25 km (0.13 nm). Depending on the elevation angle, the range bin dimensions are either 0.25 km by 1 degree or 0.25 km by 0.5 degree. All the WSR-88D products are built from these range bins. The WSR-88D product range resolutions are 0.25 km ( 0.13 nm), 0.50 km (0.27 nm), 1 km (0.54 nm), 2 km (1.1 nm), and 4 km (2.2 nm).
Table 1 contains standard WSR-88D product range resolution conversion values.
Table 1: Range Resolutions
Product Azimuthal Resolution
There are two fundamental types of base data resolution, determined by the azimuth. The first is legacy resolution base data, which is 0.25 km by 1 degree. There are lower resolution base products built from these base data. The second is super resolution (or super-res), which is available at lower elevation angles and is 0.25 km by 0.5 degree for reflectivity, velocity, and spectrum width. Section 5-6 demonstrates the difference between legacy and super-res base data, as well as the construction techniques for lower resolution base products.
Product Display Range
Base data are displayable out to a certain range from the radar. Both legacy and super-res base reflectivity are available to a display range of 248 nm. All velocity and spectrum width products are displayed to a range of 162 nm.
Table 2 contains standard WSR-88D product display range conversion values.
Table 2: Display Ranges
Product Data Levels
The data levels or precision of the WSR-88D products generated at the RPG are of four types: 3-bit, 4-bit, 8-bit, and 16-bit. A 3-bit product has 8 data levels, a 4-bit product has 16 data levels, an 8-bit product has 256 data levels, and a 16-bit product has 65536 data levels. NOTE: Currently, AWIPS only displays up to 8-bit resolution for WSR-88D products. Table 3 shows AWIPS D-2D color bars associated with 8-bit Reflectivity (top), 4-bit Reflectivity (middle), and 3-bit Spectrum Width (bottom), which are the three types of data levels for WSR-88D products in AWIPS.
Table 3: WSR-88D Product Data Levels in AWIPS
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