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Topic: Doppler radar

Related Topics

Radar

Radar gun

Types and uses of radar

Synthetic aperture radar

Millimeter Cloud Radar

3D radar

History of radar

Doppler effect

Doppler

Active Electronically Scanned Array

NEXRAD

LIDAR

Sonar

Doppler profile

Weather vane

	doppler radar (Site not responding. Last check: 2007-10-17)
		The term RADAR was suggested by S. Taylor and F. Furth of the U.S. Navy and became in November 1940 the official acronym of equipment built for radio detecting and ranging of objects.
		Pulsed-Doppler radar was developed during World War II to better detect aircraft and other moving objects in the presence of echoes from sea and land that are illuminated by microwave emissions through sidelobes of the antenna's radiation pattern.
		The earliest pulsed-Doppler radars were called MTI (moving target indication) radars in which a coherent continuous-wave (cw) oscillator, phase-locked to the random phase of the sinusoid in each transmitted pulse, is mixed with the echoes associated with that pulse.
	www.ob-ultrasound.net /doppler-radar.html (578 words)

	Interpreting Doppler Radar Velocities: speed shear wind patterns
		Normally the radar beam is pointed at an elevation angle greater than zero so that the beam, as it moves away from the radar, moves higher and higher above the surface of the earth.
		On a radar PPI display, the distance away from the radar at the center of the display represents both a change in horizontal distance and a change in vertical distance.
		Doppler velocity patterns (right) correspond to vertical wind profiles (left), where the wind barbs indicate wind speed and direction from the ground up to 24,000 feet.
	ww2010.atmos.uiuc.edu /(Gh)/guides/rs/rad/ptrn/ptrn1.rxml (462 words)

	New Page 2 (Site not responding. Last check: 2007-10-17)
		Doppler radar is one of two kinds of continuous signal radars.
		As the outgoing wave strikes an object that is approaching a radar set, the wave is reflected at a higher frequency than the frequency at which it was sent out(the train approaching).
		Doppler radar systems use the Doppler principle to tell whether rain is moving closer or going farther away.
	www.sinc.sunysb.edu /Class/cei511/doppler.htm (431 words)

	About Nexrad : Weather Underground (Site not responding. Last check: 2007-10-17)
		The radar's computers measure the frequency change of the reflected pulse of energy and then convert that change to a velocity of the object, either toward or from the radar.
		VIL is the amount of liquid water that the radar detects in a vertical column of the atmosphere for an area of precipitation.
		For very tall storms close to the radar, the maximum tilt angle of the radar (19.5 degrees) is not high enough to let the radar beam reach the top of the storm.
	www.wunderground.com /radar/help.asp (2993 words)

	JetStream - An Online School for Weather: RIDGE radar
		However, velocity data cannot be accurately unfolded and therefore the effective range with which Doppler radars can detect velocity data is limited by the frequency of the radar pulses; the higher the pulse rate, the shorter the range within which the velocity field can be determined.
		Prior to Doppler radars, the old analog type of radar continually transmitted a signal and its return would be projected on a screen as a line sweeping around the scope.
		Also these older weather radars required an operator to manually tilt the antenna up and down whenever a vertical cross section of a storm was desired, or when the upper parts of a storm needed to be investigated.
	www.srh.noaa.gov /jetstream/remote/radarfaq.htm (3273 words)

	Personal AccuWeather : Doppler Radar FAQs
		Doppler radar uses the "Doppler effect" to determine the movement of the particles (rain drops, hail, ice crystals) that are reflecting the radar's signal back to the radar.
		A NEXRAD Doppler radar will typically operate in the clear air mode when little or no precipitation is being detected within the effective range of the radar for reflectivity data (460 Km or 286 mi.).
		The radar is more sensitive when in clear air mode and is able to detect dry frontal boundaries, drizzle and snow (which typically shows up at reflectivities of 5 dBZ or lower) with greater precision and detail than when the radar is in precipitation mode.
	wwwa.accuweather.com /phoenix2/faq/adc/dopplerfaq.htm (2084 words)

	Compact Discs (Site not responding. Last check: 2007-10-17)
		Doppler Radar is defined as weather radar that measures direction and speed of a moving object, such as drops of precipitation, by determining whether the atmospheric motion is horizontally toward or away from the radar.
		This is found based on the Doppler effect, which is when objects move toward the antenna the frequency received is higher and when objects move away from the antenna the frequency is lower.
		Doppler radar is used and found as a reliable source everyday in our society.
	www.sinc.sunysb.edu /Class/cei511/9.html (497 words)

	Doppler radar - Wikipedia, the free encyclopedia
		Doppler radar uses the Doppler effect to measure the relative velocity of targets in the antenna's directional beam.
		A Doppler radar is a radar that produces a velocity measurement as one of its outputs.
		Weather radars are high resolution velocity radars, while air defense radars have a large range of velocity detection, but the accuracy in velocity is in the 10's of knots.
	en.wikipedia.org /wiki/Doppler_radar (778 words)

	Doppler Radar (Online Tornado FAQ) (Site not responding. Last check: 2007-10-17)
		Doppler radar can see not only the precipitation in a thunderstorm (through its ability to reflect microwave energy, or reflectivity), but motion of the precipitation along the radar beam.
		Doppler radar and severe storms research were joined in the early 1960s when the National Severe Storms Project began in Kansas City, and continue to this day at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma.
		In the early to mid 1990s, a national network of over 100 WSR-88D Doppler radar sites was built as part of the modernization of the National Weather Service.
	www.spc.noaa.gov /faq/tornado/doppler.htm (463 words)

	National Doppler Radar Sites
		The radar's computers measure the phase change of the reflected pulse of energy which then convert that change to a velocity of the object, either toward or from the radar.
		While the radar image may not indicate precipitation it's quite possible that the radar beam is overshooting precipitation at lower levels, especially at greater distances.
		When precipitation is occurring, the radar does not need to be as sensitive as in clear air mode as rain provides plenty of returning signals.
	weather.noaa.gov /radar/radinfo/radinfo.html (2949 words)

	USATODAY.com (Site not responding. Last check: 2007-10-17)
		Doppler refers to the principle the Austrian scientist Christian Doppler discovered in 1842.
		Doppler worked out his ideas using sound waves, long before radio, much less radar, was invented.
		The computer that's a part of a Doppler radar uses the frequency changes to show directions and speeds of the winds blowing around the raindrops, insects and other objects that reflected the radio waves.
	www.usatoday.com /weather/wdoppler.htm (331 words)

	How Radar Works (Site not responding. Last check: 2007-10-17)
		Doppler radar is now being used by Meteorologists to learn even more about weather.
		Doppler radar can not only see rain...it can see the winds inside storms...in some cases it can even track bugs and dust particles and tell a forecaster what the winds are doing in areas where there is no rain.
		Doppler radar measures the very small changes in the frequency of the signals it recieves to see winds.
	www.tco.com /weather/how.htm (304 words)

	Pulse-Doppler radar - Wikipedia, the free encyclopedia
		It is a common misconception that pulse-"doppler" radars utilize the doppler effect to calculate velocities, since it is considered impossible to measure the tiny frequency shift originated from targets moving at sub-sonic speeds when excited by very brief radar pulses.
		Pulse-doppler radar is based on the fact that targets moving with a nonzero radial velocity will introduce a phase-shift between successive pulses for the sample volume containing the target.
		If the radar is moving, such as on a fighter aircraft, or a surveillance aircraft, then much more processing will be required, as the amount of clutter in the filters will be based on platform speed, terrain under the radar, antenna depression angle, and antenna rotation/steered angle.
	en.wikipedia.org /wiki/Pulse-doppler_radar (900 words)

	Definition: Doppler
		A "Doppler" radar has the capability of measuring some information about winds (on top of the usual echo strength all radars measure) by using the Doppler effect.
		The most common wind information measured by a Doppler radar is the radial velocity, which is the component of the wind going in the direction of the radar (either towards or away).
		The height at which radar observes the weather increases with distance because the radar generally points at some elevation over the horizon.
	www.radar.mcgill.ca /define_doppler.html (281 words)

	JetStream - An Online School for Weather: Remote Sensing with Doppler radar
		The radar used by the National Weather Service is called the WSR-88D, which stands for Weather Surveillance Radar - 1988 Doppler (the prototype radar was built in 1988).
		There are 155 WSR-88D Doppler radar in the nation, including the U.S. Territory of Guam and the Commonwealth of Puerto Rico, operated by the National Weather Service and the Department of Defense.
		However, because of the very short period the radar is actually transmitting, when the time of all pulses each hour are totaled (the time the radar is actually transmitting), the radar is "on" for about 7 seconds each hour.
	www.srh.noaa.gov /jetstream/remote/doppler.htm (651 words)

	McGill S-band radar (Site not responding. Last check: 2007-10-17)
		Thanks to a major infrastructure grant, the radar transmitter, receivers, and antenna control will be replaced in the next two years.
		This radar is used for weather surveillance, providing data in real-time to various users including the local weather office, as well as for meteorological research and the development of automated algorithms of weather detection and identification.
		With a 700 kW Klystron transmitter and a 9 m (30') dish, the S-band radar is the largest weather radar in Canada.
	www.radar.mcgill.ca /s_band.html (240 words)

	JetStream - An Online School for Weather: RIDGE radar (Site not responding. Last check: 2007-10-17)
		The enhanced view of NWS Doppler radar images allows interactivity with the display providing you with the ability to customize the way you "look" at weather.
		While the radar image itself is the same as in the standard version, the geospatial ability in the enhanced version allows for the use of several features to aid the viewer.
		One method is simply that the toggle switches are preserved as you move from radar to radar using the "Adjacent Radars" arrows.
	www.srh.noaa.gov /jetstream/remote/ridge.htm (1316 words)

	Radar - DAN'S WILD WILD WEATHER PAGE
		Doppler radar can not only see rain and other forms of precipitation.
		Doppler radar can see the raindrops going in different directions and tell a forecaster precisely where the tornado is in some cases.
		Doppler radar measures the very small changes in the frequency of the signals it receives to see determine winds.
	www.wildwildweather.com /radar.htm (436 words)

	Radar Meteorology: online remote sensing guide
		Radars have an important role in the field of meteorology.
		Advanced Doppler radar technology goes beyond simple detection to providing high resolution reflectivity and estimated velocity data, which is vital to short term forecasting and severe weather prediction.
		The navigation menu (left) for this module is called "Radars" and the menu items are arranged in a recommended sequence, beginning with this introduction.
	ww2010.atmos.uiuc.edu /(Gh)/guides/rs/rad/home.rxml (209 words)

	University of North Dakota \| UND Doppler Radar
		In 1993, the radar moved to the top of Clifford Hall at the west end of the UND campus.
		In January 2003, the radar was upgraded with a SIGMET, Inc. digital receiver and signal processor (RVP8), radar antenna controller (RCP8), radar control, analysis and display software (IRIS).
		In January 2004, the radar was upgraded to a dual-polarized system and has been operated in support of the research and academic programs of the Department of Atmospheric Sciences.
	radar.atmos.und.edu (136 words)

	asahi.com：Haneda picks up new lidar system - ENGLISH (Site not responding. Last check: 2007-10-17)
		Tokyo's Haneda Airport will be the nation's first to have a Doppler lidar system to detect the wind shear and potentially dangerous downbursts that can interfere with takeoffs and landings.
		Doppler radar observes rain and snow patterns within a 100-kilometer radius, and tracks the movement of clouds and wind.
		By combining the radar and lidar systems, agency officials said they hoped to create a warning system for aircraft that will be effective in all weather conditions.
	www.asahi.com /english/Herald-asahi/TKY200611290181.html (444 words)

	Local News \| News for Charlotte, North Carolina \| WCNC.com \| Local Doppler
		The 14-foot radar dish generates a narrow radar beam that slices through storms.
		Live Doppler Plus can track storms down to the city and street with a timeline to tell you when the storm will arrive in your neighborhood.
		Rain rates, radar estimated rainfall totals, wind shear and storm top data are also available on Live Doppler Plus.
	www.wcnc.com /weather/doppler (157 words)

	Doppler Radar (Site not responding. Last check: 2007-10-17)
		Doppler radar images of the F-5 tornado that swept away part of Moore, Oklahoma in the Oklahoma City area outbreak of May 3, 1999.
		On the velocity display, the blocks of green color show areas where the wind is moving toward the radar equipment.
		The wind is spinning around a central vortex in this region where the red and green are in contact, rushing quickly away from the radar in the red places and toward it in the green ones.
	www.tapestryweb.org /tornado/doppler.html (327 words)

	UM-Weather: Radar & Satellite (Site not responding. Last check: 2007-10-17)
		To obtain the latest Nexrad graphic for a particular city, click the radar icon.
		Satellite imagery may be obtained by clicking anywhere else on the map.
		Radar and satellite data courtesy of Intellicast, TWC, and other sources.
	cirrus.sprl.umich.edu /wxnet/radsat.html (45 words)

	IWS Radar Graphics and Data
		Loop of radar imagery for the continental United States.
		Loop of radar imagery for Puerto Rico/Virgin Islands.
		Information about access to radar data in its original coded data format via FTP or multicast.
	weather.noaa.gov /radar (143 words)

	ABC 33/40 Weather Center - Doppler Radar
		These Pinpoint Doppler Radar images are the exclusive property of ABC 33/40 in Birmingham.
		ABC 33/40's Pinpoint Doppler radar is the most powerful and sophisticated broadcast weather radar system in north-central Alabama.
		Scanning the Alabama sky from a mountain-top location in northern Shelby county, Pinpoint Doppler radar can see distant storms thanks to a large 14 foot diameter antenna atop a 100 foot tower on Double Oak Mountain.
	www.abc3340.com /weather/doppler.html (226 words)

	NWS radar image from Melbourne, FL
		Radar Precip Est From 03:22 AM EST Mon Dec 04 2006
		Radar Precip Est From 06:06 AM EST Fri Dec 01 2006
		Java is necessary for radar looping and is best optimized using Java version 1.4.2 or higher.
	radar.weather.gov /radar.php?rid=mlb&product=N0R&overlay=11101111&loop=no (88 words)

	Links to experimental radar images from the National Weather Service
		RIDGE (Radar Integrated Display with Geospatial Elements) is the result of a partnership with The North Texas Council of Governments and Southern Region Headquarters of the National Weather Service.
		Leon Minton(SRH) together with Keith Stellman designed a method to quickly and efficiently generate the "standard" images using the existing RIDGE images, legends, warnings, and overlays.
		Java must be enabled for looping of the individual radar sites.
	radar.weather.gov /credits.html (296 words)

	Weather Doppler Radar \| St. Louis \| KMOV.com \| St. Louis, MO
		In the event of threatening weather, turn to News 4 St. Louis for the latest radar, warnings and conditions.
		If you play a loop of the radar and you don't see individual storms moving across the screen or if the image does not show any significant change and the colors appear to radiate out from the radar site (in Weldon Springs) then it's likely false returns.
		This example is fairly extreme but many times the radar site may be surrounded by a nearly circular pattern of light green.
	www.kmov.com /weather/doppler.html (162 words)

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