WSR-74

WSR-74 RADARs are Weather Surveillance Radars designed in 1974. The National Weather Service added them to the existing network of the WSR-57 model to improve forecasts and severe weather warnings.

Radar properties

There are two types in the WSR-74 series, which are almost identical except for operating frequency. [ [http://www.its.bldrdoc.gov/pub/oprad/sect7.pdf http://www.its.bldrdoc.gov/pub/oprad/sect7.pdf] ] The WSR-74C (used for local warnings) operates in the C band, and the WSR-74S (used in the national network) operates in the S band (like the WSR-57 and the current WSR-88D). S band frequencies are better suited for long range.

The WSR-74C uses a wavelength of 5.4 cm.Paul Sirvatka. "WSR - Weather Surveillance Radar." Radar. College of DuPage. 4 Apr. 2006 [http://weather.cod.edu/sirvatka/radar.html ] .] It also has a dish diameter of 8 feet, and a maximum range of 579 km (313 nm).

History

The WSR-57 network was very spread out, with 66 radars to cover the entire country. There was little to no overlap in case one of these vacuum-tube radars went down for maintenance. The WSR-74 was introduced as a "gap filler", as well as an updated radar that, among other things, was transistor-based.Roger C. Whiton, et al. "History of Operational Use of Weather Radar by U.S. Weather Services. Part I: The Pre-NEXRAD Era." Weather and Forecasting: Vol. 13, No. 2, pp. 219–243. 19 Feb. 1998. American Meteorological Society. 5 Apr. 2006 [http://ams.allenpress.com/amsonline/?request=get-document&doi=10.1175%2F1520-0434(1998)013%3C0219:HOOUOW%3E2.0.CO%3B2 ] .]

WSR-74C radars were generally local-use radars that didn't operate unless severe weather was expected, while WSR-74S radars were generally used to replace WSR-57 radars in the national weather surveillance network. When a network radar went down, a nearby local radar might have to supply updates like a network radar. [ [http://www.stormtrack.org/forum/viewtopic.php?t=9498 Stormtrack.org Forum 9498] ] Corpus Christi became the first operational site for the WSR-74C on February 1, 1976.

128 [ [http://sysu1.wsicorp.com/unidata/intro.html http://sysu1.wsicorp.com/unidata/intro.html] ] of the WSR-57 and WSR-74 model radars were spread across the country as the National Weather Service's radar network until the 1990s. They were gradually replaced by the WSR-88D model (Weather Surveillance Radar - 1988, Doppler), constituting the NEXRAD network. The WSR-74 had served the NWS for two decades.

Thirteen WSR-74Cs still have not been decommissioned and, of those, eight remain in active use today. No WSR-74Ss are in the NWS inventory today, having been replaced by the WSR-88D. Some of these radars are in commercial use.

Radar sites

WSR-74 sites include the following two categories: [ [http://books.nap.edu/books/NI000004/html/9.html NWS Modernization Committee. "Toward a New National Weather Service - Assessment of NEXRAD Coverage and Associated Weather Services".] ] [ [http://www.stormtrack.org/forum/viewtopic.php?t=10344 Stormtrack.org Forum 10344] ]

See also

References