RADAR
What is radar?
Radar is an acronym for "RAdio Detection And Ranging," and it uses radio waves to detect objects in the atmosphere. It was first devised in 1904 by the German inventor Christian Hulsmeyer (1881-1957), who called his radar detector a "telemobiloscope" and patented the device in 1906. The original purpose of his invention was for ships to be able to detect each other so that in poor weather conditions (e.g., heavy fog) they would not run into each other. Sadly, this brilliant invention did not catch on at the time; if it had, some speculate that the 1912 Titanic disaster could have been avoided. Another concept that Hulsmeyer came up with was the remote control. He believed, correctly, that radio waves could be used to turn mechanical devices on and off. Again, people ignored the concept and he never got the credit he deserved.
When did radar finally catch on, and who gets the credit?
In 1935—over three decades after Hulsmeyer first proposed the idea—radar technology came into its own through the work of British scientist Robert Watson-Watt (1892-1973), along with H.E. Wimperis (1876-1960), Henry Tizard (1885-1959), and A.F. Wilkins. Working for the British government, Watson-Watt was given the assignment of investigating whether Germany's Adolf Hitler could carry out a threat of creating a weapon using radio waves. Watson-Watt knew this was an impossibility, but he saw another potential use. Using shortwave radio transmitters from the British Broadcasting Corporation, he and his colleagues created the first practical radar technology. Radar was used to detect attacking German airplanes during World War II, and was credited with swaying the 1940 Battle of Britain in England's favor.
Who should be credited with inventing weather radar?
No one person decided to use radar for weather forecasts. With the technology already in place, it was simply adapted to this purpose when experiments in Britain and the United States showed that radio waves bounced off clouds. Radar was first used to specifically obtain weather data in 1949, but it was not until the mid-1950s that a weather station using radar technology was established in the United States. This happened after the Eastern seaboard was hit by two vicious hurricanes in 1954 and 1955. The U.S. Weather Bureau was then authorized by Congress to create a national weather radar grid, and so the Weather Surveillance Radar (WSR-57) was founded in 1957. WSR systems used vacuum tubes and other technologies that were
The first National Severe Storms Laboratory radar, shown in this 1971 photo, was constructed in Norman, Oklahoma. This early radar, with a 30-foot (3-meter) dish, eventually led to the development of the NEXRAD WSR-88D radar. (NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory)
becoming outdated by the late 1970s. Despite the fact that vacuum tubes were in short supply, and other parts had to be hand-machined in order to keep the weather system running, Congress did not approve replacing the system until the 1990s.
What is Doppler radar?
Doppler radar measures frequency differences between signals bouncing off objects moving away from or toward it. By measuring the difference between the transmitted and received frequencies, Doppler radar calculates the speed of the air in which the rain, snow, ice crystals, and even insects are moving. It can then be used to predict speed and direction of wind and amount of precipitation associated with a storm.
What replaced the WSR-57s?
WSR-74s were added to the radar grid in 1974 and were used in conjunction with the older "57s," as they were called. It was not until 1988, however, that the Next Generation Radar (NEXRAD; also called WSR-88D) were built using the newer Doppler technology. The first NEXRAD was deployed in Norman, Oklahoma, in 1990. There are now 160 NEXRAD radar stations throughout the United States.
