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The AN/CPS-9 radar, the first radar specifically designed for meteorological use, was produced in the United States around 1949 [1] and unveiled by the Air Weather Service (now the Air Force Weather Agency) in 1954. [2]


AN/CPS-9 installations

The AN/CPS-9 was installed at military bases worldwide, as well as laboratories, such as the Air Force Cambridge Research Center, the Air Force Geophysics Laboratory (AFGL), the Phillips Laboratory (PL), and all weather training facilities and universities. Fifty-six CPS-9s were produced for all services combined, [3] and less than 50 went into operational use in the Air Force; APQ-13s had to be kept in operation at facilities that did not receive a CPS-9. The first operational CPS-9 was installed at Maxwell AFB, Alabama, on 20 June 1954; that radar remained operational for 30 years before finally being replaced on 14 July 1984 by a more modern radar, the AN/FPS-77 (Fuller 1990a). In 1966, the Air Weather Service still had 40 CPS-9s in operation. By 1974, the number was reduced to 11. None are in the operational inventory today. [4]

Texas A&M University was one of the universities to receive a CPS-9. The Condon Report on Unidentified Flying Objects refers to Texas A&M research using the AN/CPS-9. [5]

Radar properties

The CPS-9 became known for having good sensitivity. However, nearby rain would attenuate the signal from distant rain, making rainfall measurement less accurate. Hail may also have diminished the radar returns from storms, due to the way that X band radar energy reflects off hail. Despite this, researchers could identify storms strong enough to produce hail by looking for areas with those diminished returns. [4]

Related Research Articles

Hail Form of solid precipitation

Hail is a form of solid precipitation. It is distinct from ice pellets, though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fall in cold weather, while hail growth is greatly inhibited during cold surface temperatures.

Thunderstorm Type of weather with lightning and thunder

A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are sometimes called thundershowers. Thunderstorms occur in a type of cloud known as a cumulonimbus. They are usually accompanied by strong winds and often produce heavy rain and sometimes snow, sleet, or hail, but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in a series or become a rainband, known as a squall line. Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes. Some of the most persistent severe thunderstorms, known as supercells, rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes a deviation in their course at a right angle to the wind shear direction.

Doppler radar Type of radar equipment

A Doppler radar is a specialized radar that uses the Doppler effect to produce velocity data about objects at a distance. It does this by bouncing a microwave signal off a desired target and analyzing how the object's motion has altered the frequency of the returned signal. This variation gives direct and highly accurate measurements of the radial component of a target's velocity relative to the radar.

NEXRAD Nationwide network of Doppler weather radars operated by the U.S. National Weather Service

NEXRAD or Nexrad is a network of 160 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce, the Federal Aviation Administration (FAA) within the Department of Transportation, and the U.S. Air Force within the Department of Defense. Its technical name is WSR-88D.

Lockheed WC-130 Weather aircraft series by Lockheed

The Lockheed WC-130 is a high-wing, medium-range aircraft used for weather reconnaissance missions by the United States Air Force. The aircraft is a modified version of the C-130 Hercules transport configured with specialized weather instrumentation including a dropsonde deployment/receiver system and crewed by a meteorologist for penetration of tropical cyclones and winter storms to obtain data on movement, size and intensity.

Weather radar Radar used to locate and monitor meteorological conditions

Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type. Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the intensity of the precipitation. Both types of data can be analyzed to determine the structure of storms and their potential to cause severe weather.

Index of meteorology articles

This is a list of meteorology topics. The terms relate to meteorology, the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting.

The National Severe Storms Laboratory (NSSL) is a National Oceanic and Atmospheric Administration (NOAA) weather research laboratory under the Office of Oceanic and Atmospheric Research. It is one of seven NOAA Research Laboratories (RLs).

QuikSCAT Earth observation satellite

The NASA QuikSCAT was an Earth observation satellite carrying the SeaWinds scatterometer. Its primary mission was to measure the surface wind speed and direction over the ice-free global oceans. Observations from QuikSCAT had a wide array of applications, and contributed to climatological studies, weather forecasting, meteorology, oceanographic research, marine safety, commercial fishing, tracking large icebergs, and studies of land and sea ice, among others. This SeaWinds scatterometer is referred to as the QuikSCAT scatterometer to distinguish it from the nearly identical SeaWinds scatterometer flown on the ADEOS-2 satellite.

Aggie Doppler Radar

The Aggie Doppler Radar (ADRAD) is a Doppler weather radar located on the roof of the Eller Oceanography & Meteorology Building on the Texas A&M University campus in College Station, Texas.

Canadian weather radar network

The Canadian weather radar network consists of 31 weather radars spanning Canada's most populated regions. Their primary purpose is the early detection of precipitation, its motion and the threat it poses to life and property.

The AN/APS-2, originally known as ASG, was a surface search radar developed by Philco originally for use in US Coast Guard blimps to detect German submarines. It proved better than several similar models then being built, and was ordered by the RAF Coastal Command where it was known as ASV Mark V. It was used primarily on British Liberator GR bombers, where they were instrumental in closing the Mid-Atlantic Gap and the subsequent destruction of the German U-boat fleet in May/June 1943.

AN/APQ-13 Type of aircraft radar

The AN/APQ-13 radar was an American ground scanning radar developed by Bell Laboratories, Western Electric, and MIT as an improved model of the airborne H2X radar, itself developed from the first ground scanning radar, the British H2S radar. It was used on B-29s during World War II in the Pacific theater for high altitude area bombing, search and navigation. Computation for bombing could be performed by an impact predictor. A range unit permitted a high degree of accuracy in locating beacons. The radome was carried on the aircraft belly between the bomb bays and was partially retractable on early models. The radar operated at a frequency of 9375 ± 45 megahertz and used a superheterodyne receiver.


The WSR-1 or Weather Surveillance Radar-1 was one of the first weather radars and the first used by a civilian organization in the US. The WSR-1 series was a modified version of the AN/APS-2F radar, which the Weather Bureau acquired from the Navy. The WSR-1A, WSR-3, and WSR-4 were also variants of this radar. The first WSR-1 in the USA was at Washington National Airport in Washington, D.C. in 1947, and the last WSR-3 was retired by 1978.

Air-mass thunderstorm Thunderstorm that is generally weak and usually not severe

An air-mass thunderstorm, also called an "ordinary", "single cell", or "garden variety" thunderstorm, is a thunderstorm that is generally weak and usually not severe. These storms form in environments where at least some amount of Convective Available Potential Energy (CAPE) is present, but very low levels of wind shear and helicity. The lifting source, which is a crucial factor in thunderstorm development, is usually the result of uneven heating of the surface, though they can be induced by weather fronts and other low-level boundaries associated with wind convergence. The energy needed for these storms to form comes in the form of insolation, or solar radiation. Air-mass thunderstorms do not move quickly, last no longer than an hour, and have the threats of lightning, as well as showery light, moderate, or heavy rainfall. Heavy rainfall can interfere with microwave transmissions within the atmosphere.

Severe weather Any dangerous meteorological phenomenon

Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. Types of severe weather phenomena vary, depending on the latitude, altitude, topography, and atmospheric conditions. High winds, hail, excessive precipitation, and wildfires are forms and effects of severe weather, as are thunderstorms, downbursts, tornadoes, waterspouts, tropical cyclones, and extratropical cyclones. Regional and seasonal severe weather phenomena include blizzards (snowstorms), ice storms, and duststorms. Extreme weather phenomena which cause extreme heat, cold, wetness or drought often will bring severe weather events. One of the principle effects of anthropogenic climate change is changes in severe and extreme weather patterns.

Convective storm detection is the meteorological observation, and short-term prediction, of deep moist convection (DMC). DMC describes atmospheric conditions producing single or clusters of large vertical extension clouds ranging from cumulus congestus to cumulonimbus, the latter producing thunderstorms associated with lightning and thunder. Those two types of clouds can produce severe weather at the surface and aloft.

General Electric AN/CPS-6 Radar

The AN/CPS-6 was a medium-range search/height finder Radar used by the United States Air Force Air Defense Command.

The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.

Multifunction Phased Array Radar

Multifunction Phased Array Radar (MPAR) was an experimental Doppler radar system that utilized phased array technology. MPAR could scan at angles as high as 60 degrees in elevation, and simultaneously track meteorological phenomena, biological flyers, non-cooperative aircraft, and air traffic. From 2003 through 2016, there was one operational MPAR within the mainland United States—a repurposed AN/SPY-1A radar set loaned to NOAA by the U.S. Navy. The MPAR was decommissioned and removed in 2016.


  1. Raghavan, S. 2003. Radar meteorology. Dordrecht: Kluwer Academic Publishers. P. 3
  2. NOAA Legacy Timeline - 1900–1969 <>.
  3. Williams 1953
  4. 1 2 3 4 5 6 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 February 1998. American Meteorological Society. 5 April 2006 <> [ permanent dead link ].
  5. in its appendix