Editing Weather radar (section)

==History==
[[File:Typhoon Cobra, 18 December 1944 east of Luzon.jpg|thumb|[[Typhoon Cobra]] as seen on a ship's radar screen in December 1944.]]
During World War II, military radar operators noticed noise in returned echoes due to rain, snow, and [[Ice pellets|sleet]]. After the war, military scientists returned to civilian life or continued in the Armed Forces and pursued their work in developing a use for those echoes. In the United States, [[David Atlas]]<ref>{{cite book|title=Radar in meteorology|editor1-last=Atlas |editor1-first=David |editor-link=David Atlas|series=[[Louis J. Battan|Battan Memorial]] and 40th Anniversary Radar Meteorology Conference|publisher=[[American Meteorological Society|AMS]]|location= Boston, MA| isbn=978-0-933876-86-6 |year=1990|doi=10.1007/978-1-935704-15-7}}{{ISBN|978-1-935704-15-7}}, 806 pages, AMS Code RADMET.</ref> at first working for the [[United States Air Force|Air Force]] and later for [[Massachusetts Institute of Technology|MIT]], developed the first operational weather radars. In Canada, [[J. Stewart Marshall|J.S. Marshall]] and R.H. Douglas formed the "Stormy Weather Group" in Montreal.<ref>{{cite web|year=2000|title=Stormy Weather Group|first=R. H. |last=Douglas|publisher=[[McGill University]]|url=http://www.radar.mcgill.ca/who-we-are/history.html|access-date=2006-05-21|archive-url=https://web.archive.org/web/20110706185139/http://www.radar.mcgill.ca/who-we-are/history.html|archive-date=6 July 2011}}</ref><ref>{{cite book|title=Radar in meteorology|first=R. H. |last=Douglas|editor1-first=David |editor1-last=Atlas |editor-link=David Atlas|series=[[Louis J. Battan|Battan Memorial]] and 40th Anniversary Radar Meteorology Conference|publisher=[[American Meteorological Society|AMS]]|location= Boston, MA|year=1990|doi=10.1007/978-1-935704-15-7 |chapter=Chapter 8- The Stormy Weather Group (Canada)|pages= 61–68|isbn=978-1-935704-15-7 }}</ref> Marshall and his doctoral student Walter Palmer are well known for their work on the [[Raindrop size distribution|drop size distribution]] in mid-latitude rain that led to understanding of the Z-R relation, which correlates a given radar [[reflectivity]] with the rate at which rainwater is falling. In the United Kingdom, research continued to study the radar echo patterns and weather elements such as [[Nimbostratus cloud|stratiform]] rain and [[Atmospheric convection|convective clouds]], and experiments were done to evaluate the potential of different wavelengths from 1 to 10 centimeters. By 1950 the UK company [[EKCO]] was demonstrating its airborne 'cloud and collision warning search radar equipment'.<ref>{{Cite web | url=http://www.flightglobal.com/pdfarchive/view/1950/1950%20-%201758.html | title=Grouped exhibits &#124; illustrated mainly &#124; flight photographs &#124; 1950 &#124; 1758 &#124; Flight Archive}}</ref>
[[File:1965May06 1919.jpg|thumb|left|1960s radar technology detected [[Early May 1965 tornado outbreak|tornado]]-producing [[supercell]]s over the [[Minneapolis-Saint Paul]] metropolitan area.]]
Between 1950 and 1980, reflectivity radars, which measure the position and intensity of precipitation, were incorporated by weather services around the world. The early meteorologists had to watch a [[cathode-ray tube]]. In 1953 Donald Staggs, an electrical engineer working for the Illinois State Water Survey, made the first recorded radar observation of a "[[hook echo]]" associated with a tornadic thunderstorm.<ref>{{cite web|year=2008|title=The First Tornadic Hook Echo Weather Radar Observations|work=[[Colorado State University]]|url=http://www.chill.colostate.edu/w/CHILL_history#The_First_Tornadic_Hook_Echo_Weather_Radar_Observations|access-date=2008-01-30}}</ref>

The first use of weather radar on television in the United States was in September 1961. As [[Hurricane Carla]] was approaching the state of Texas, local reporter [[Dan Rather]], suspecting the hurricane was very large, took a trip to the U.S. [[Weather Bureau]] [[WSR-57]] radar site in [[Galveston, Texas|Galveston]] in order to get an idea of the size of the storm. He convinced the bureau staff to let him broadcast live from their office and asked a meteorologist to draw him a rough outline of the [[Gulf of Mexico]] on a transparent sheet of plastic. During the broadcast, he held that transparent overlay over the computer's black-and-white radar display to give his audience a sense both of Carla's size and of the location of the storm's eye. This made Rather a national name and his report helped in the alerted population accepting the evacuation of an estimated 350,000 people by the authorities, which was the largest evacuation in US history at that time. Just 46 people were killed thanks to the warning and it was estimated that the evacuation saved several thousand lives, as the smaller [[1900 Galveston hurricane]] had killed an estimated 6000-12000 people.<ref>{{cite report|url=https://www.theatlantic.com/technology/archive/2012/10/dan-rather-showed-the-first-radar-image-of-a-hurricane-on-tv/264246/ |title=Dan Rather Showed the First Radar Image of a Hurricane on TV|journal=The Atlantic|author=Megan Garber |date=29 October 2012}}</ref>

During the 1970s, radars began to be standardized and organized into networks. The first devices to capture radar images were developed. The number of scanned angles was increased to get a three-dimensional view of the precipitation, so that horizontal cross-sections ([[CAPPI]]) and vertical cross-sections could be performed. Studies of the organization of thunderstorms were then possible for the [[Alberta Hail Project]] in Canada and [[National Severe Storms Laboratory]] (NSSL) in the US in particular.

The NSSL, created in 1964, began experimentation on dual [[Polarization (waves)|polarization]] signals and on [[Doppler effect]] uses. In May 1973, a tornado devastated [[Union City, Oklahoma]], just west of [[Oklahoma City]]. For the first time, a Dopplerized 10&nbsp;cm wavelength radar from NSSL documented the entire life cycle of the tornado.<ref name=NSSL>{{cite web|date=29 October 2004|work=NOAA Magazine|title=Weather radar development highlight of the National Severe Storms Laboratory first 40 years|first=Susan|last=Cobb|publisher=[[National Oceanic and Atmospheric Administration]]|url=http://www.magazine.noaa.gov/stories/mag151.htm|access-date=2009-03-07|archive-url=https://web.archive.org/web/20130215212436/http://www.magazine.noaa.gov/stories/mag151.htm|archive-date=15 February 2013}}</ref> The researchers discovered a [[mesoscale meteorology|mesoscale]] rotation in the cloud aloft before the tornado touched the ground – the [[tornadic vortex signature]]. NSSL's research helped convince the [[National Weather Service]] that Doppler radar was a crucial forecasting tool.<ref name=NSSL/> The [[1974 Super Outbreak|Super Outbreak]] of tornadoes on 3–4 April 1974 and their devastating destruction might have helped to get funding for further developments.{{Citation needed|date=March 2009}}

[[File:NEXRAD and thunderstorm in New Underwood, South Dakota, 2004 - NOAA Photo Library Wea01195.jpg|thumb|NEXRAD in South Dakota with a [[supercell]] in the background.]]
Between 1980 and 2000, weather radar networks became the norm in North America, Europe, Japan and other developed countries. Conventional radars were replaced by Doppler radars, which in addition to position and intensity could track the relative velocity of the particles in the air. In the United States, the construction of a network consisting of 10&nbsp;cm radars, called [[NEXRAD]] or WSR-88D (Weather Surveillance Radar 1988 Doppler), was started in 1988 following NSSL's research.<ref name=NSSL/><ref>{{cite web|title=NSSL Research Tools: Radar|url=http://www.nssl.noaa.gov/tools/radar/|publisher=NSSL|access-date=1 March 2014|archive-url=https://web.archive.org/web/20161014053017/http://www.nssl.noaa.gov/tools/radar/|archive-date=14 October 2016}}</ref> In Canada, [[Environment Canada]] constructed the [[King City weather radar station|King City]] station,<ref>{{Cite journal|title=The King City Operational Doppler Radar: Development, All-Season Applications and Forecasting|first1=C.L.|last1=Crozier|first2=P.I.|last2=Joe|first3=J.W.|last3=Scott|first4=H.N.|last4=Herscovitch|first5=T.R.|last5=Nichols|volume=29|issue=3|year=1991|pages=479–516|journal=Atmosphere-Ocean|doi=10.1080/07055900.1991.9649414|doi-access=free|bibcode=1991AtO....29..479C }}</ref> with a 5&nbsp;cm research Doppler radar, by 1985; McGill University dopplerized its radar ([[J. S. Marshall Radar Observatory]]) in 1993. This led to a complete [[Canadian weather radar network|Canadian Doppler network]]<ref name=location>{{cite web|url=http://www.msc-smc.ec.gc.ca/projects/nrp/Montreal_e.cfm |title=Information about Canadian radar network |work=The National Radar Program |publisher=Environment Canada |year=2002 |access-date=2006-06-14  |archive-url=https://web.archive.org/web/20040629014717/http://www.msc-smc.ec.gc.ca/projects/nrp/Montreal_e.cfm |archive-date=29 June 2004 }}</ref> between 1998 and 2004. France and other European countries had switched to Doppler networks by the early 2000s. Meanwhile, rapid advances in computer technology led to algorithms to detect signs of severe weather, and many applications for media outlets and researchers.

After 2000, research on dual polarization technology moved into operational use, increasing the amount of information available on precipitation type (e.g. rain vs. snow). "Dual polarization" means that microwave radiation which is [[Polarization (waves)|polarized]] both horizontally and vertically (with respect to the ground) is emitted. Wide-scale deployment was done by the end of the decade or the beginning of the next in some countries such as the United States, France,<ref>[url=http://ams.confex.com/ams/pdfpapers/96217.pdf] ''The PANTHERE project and the evolution of the French operational radar network and products: Rain estimation, Doppler winds, and dual polarization'', Parent du Châtelet, Jacques et al. [[Météo-France]] (2005) 32nd Radar Conference of the [[American Meteorological Society]], Albuquerque NM</ref> and Canada. In April 2013, all United States [[National Weather Service]] NEXRADs were completely dual-polarized.<ref name=Dualpol-NOAA/>

Since 2003, the U.S. [[National Oceanic and Atmospheric Administration]] has been experimenting with [[phased-array radar]] as a replacement for conventional parabolic antenna to provide more time resolution in [[atmospheric sounding]]. This could be significant with severe thunderstorms, as their evolution can be better evaluated with more timely data.

Also in 2003, the [[National Science Foundation]] established the [[Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere]] (CASA), a multidisciplinary, multi-university collaboration of engineers, computer scientists, meteorologists, and sociologists to conduct fundamental research, develop enabling technology, and deploy prototype engineering systems designed to augment existing radar systems by sampling the generally undersampled lower troposphere with inexpensive, fast scanning, dual polarization, mechanically scanned and phased array radars.

In 2023, the private American company [[Tomorrow.io]] launched a [[Ka-band]] [[space-based radar]] for weather observation and forecasting.<ref>{{Cite web|url=https://www.tomorrow.io/blog/tomorrow-ios-historic-satellite-launch-paves-way-for-groundbreaking-advancement-in-global-weather-forecasting/|title=Tomorrow.io's Historic Satellite Launch Paves Way for Groundbreaking Advancement in Global Weather Forecasting|date=14 May 2023|website=Tomorrow.io}}</ref><ref>{{Cite web|url=https://www.cnbc.com/2023/05/16/tomorrowio-plans-constellation-of-radar-satellites-for-forecasting.html|title=Weather intelligence company aims to revolutionize forecasting with a constellation of radar satellites|first=Diana|last=Olick|date=16 May 2023|website=CNBC}}</ref>