27:
411:
high-frequency sound. An ultrasonic anemometer has two or three pairs of sound transmitters and receivers. Each transmitter constantly beams high-frequency sound to its receiver. Electronic circuits inside measure the time it takes for the sound to make its journey from each transmitter to the corresponding receiver. Depending on how the wind blows, some of the sound beams will be affected more than the others, slowing it down or speeding it up very slightly. The circuits measure the difference in speeds of the beams and use that to calculate how fast the wind is blowing.
399:
445:
256:
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mounted 10 m above ground level (and thus 64 m above sea level). During the cyclone, several extreme gusts of greater than 83 m/s (300 km/h; 190 mph; 161 kn; 270 ft/s) were recorded, with a maximum 5-minute mean speed of 49 m/s (180 km/h; 110 mph; 95 kn; 160 ft/s); the extreme gust factor was on the order of 2.27–2.75 times the mean wind speed. The pattern and scales of the gusts suggest that a
972:
419:, which are used to create the separate standing-wave patterns at ultrasonic frequencies. As wind passes through the cavity, a change in the wave's property occurs (phase shift). By measuring the amount of phase shift in the received signals by each transducer, and then by mathematically processing the data, the sensor is able to provide an accurate horizontal measurement of wind speed and direction.
39:
391:
198:
describes the difference in air pressure between two points in the atmosphere or on the surface of the Earth. It is vital to wind speed, because the greater the difference in pressure, the faster the wind flows (from the high to low pressure) to balance out the variation. The pressure gradient, when
455:
In the United States, the wind speed used in design is often referred to as a "3-second gust", which is the highest sustained gust over a 3-second period having a probability of being exceeded per year of 1 in 50 (ASCE 7-05, updated to ASCE 7-16). This design wind speed is accepted by most building
488:
Historically, wind speeds have been reported with a variety of averaging times (such as fastest mile, 3-second gust, 1-minute, and mean hourly) which designers may have to take into account. To convert wind speeds from one averaging time to another, the Durst Curve was developed, which defines the
359:
on 3 May, although another figure of 142 m/s (510 km/h; 320 mph; 276 kn; 470 ft/s) has also been quoted for the same tornado. Yet another number used by the Center for Severe
Weather Research for that measurement is 135 ± 9 m/s (486 ± 32 km/h;
295:
of 113.3 m/s (408 km/h; 253 mph; 220.2 kn; 372 ft/s) The wind gust was evaluated by the WMO Evaluation Panel, who found that the anemometer was mechanically sound and that the gust was within statistical probability and ratified the measurement in 2010. The anemometer was
410:
Unlike traditional cup-and-vane anemometers, ultrasonic wind sensors have no moving parts and are therefore used to measure wind speed in applications that require maintenance-free performance, such as atop wind turbines. As the name suggests, ultrasonic wind sensors measure the wind speed using
414:
Acoustic resonance wind sensors are a variant of the ultrasonic sensor. Instead of using time of flight measurement, acoustic resonance sensors use resonating acoustic waves within a small purpose-built cavity. Built into the cavity is an array of
375:
has winds of 2,400 m/s (8,600 km/h; 4,700 kn). In a press release, the
University announced that the methods used from measuring HD 189733b's wind speeds could be used to measure wind speeds on Earth-like exoplanets.
608:"The Icelandic Meteorological Office now uses the SI (Systeme Internationale d'Unites) measurement metres per second (m/s) other Nordic meteorological institutes have used this system for years with satisfactory results"
331:) may greatly exceed these values but have never been accurately measured. Directly measuring these tornadic winds is rarely done, as the violent wind would destroy the instruments. A method of estimating speed is to use
406:
An anemometer is one of the tools used to measure wind speed. A device consisting of a vertical pillar and three or four concave cups, the anemometer captures the horizontal movement of air particles (wind speed).
618:
International Civil
Aviation Organization – International Standards and Recommended Practices – Units of Measurement to be Used in Air and Ground Operations – Annex 5 to the Convention on International Civil
568:
Brun, P., Zimmermann, N.E., Hari, C., Pellissier, L., Karger, D.N. (preprint): Global climate-related predictors at kilometre resolution for the past and future. Earth Syst. Sci. Data
Discuss.
351:, marking the fastest winds ever observed by radar in history. In 1999, a mobile radar measured winds up to 135 m/s (490 km/h; 300 mph; 262 kn; 440 ft/s) during the
452:
Wind speed is a common factor in the design of structures and buildings around the world. It is often the governing factor in the required lateral strength of a structure's design.
459:
In Canada, reference wind pressures are used in design and are based on the "mean hourly" wind speed having a probability of being exceeded per year of 1 in 50. The reference
524:
307:
Currently, the second-highest surface wind speed ever officially recorded is 103.266 m/s (371.76 km/h; 231.00 mph; 200.733 kn; 338.80 ft/s) at the
801:
646:"Documentation and verification of the world extreme wind gust record: 113.3 m s–1 on Barrow Island, Australia, during passage of tropical cyclone Olivia"
588:
747:
662:
738:"Comparison of Tornado Damage Characteristics to Low-Altitude WSR-88D Radar Observations and Implications for Tornado Intensity Estimation"
175:
Wind speed is affected by a number of factors and situations, operating on varying scales (from micro to macro scales). These include the
582:
137:
909:
Kapartis, Savvas (1999) "Anemometer employing standing wave normal to fluid flow and travelling wave normal to standing wave"
402:
FT742-DM acoustic resonance wind sensor, one of the instruments now used to measure wind speed at Mount
Washington Observatory
737:
498:
352:
42:
Global distribution of wind speed at 10m above ground averaged over the years 1981–2010 from the CHELSA-BIOCLIM+ data set
489:
relation between probable maximum wind speed averaged over some number of seconds to the mean wind speed over one hour.
1012:
1002:
539:
284:
163:(ft/s) are also sometimes used to measure wind speeds. Historically, wind speeds have also been classified using the
129:
360:
302 ± 20 mph; 262 ± 17 kn; 443 ± 30 ft/s). However, speeds measured by
308:
755:
710:
849:
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260:
26:
518:
874:
924:
666:
280:
20:
316:
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315:. The anemometer, specifically designed for use on Mount Washington, was later tested by the US
167:, which is based on visual observations of specifically defined wind effects at sea or on land.
751:
742:
416:
344:
688:
513:
456:
codes in the United States and often governs the lateral design of buildings and structures.
311:
Observatory 1,917 m (6,288 ft) above sea level in the US on 12 April 1934, using a
225:). The Rossby waves are themselves a different wind speed from that experienced in the lower
592:
348:
105:
398:
8:
1007:
645:
632:"The reason why sea winds are measured in knots at all has to do with maritime tradition"
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145:
109:
81:
187:, and local weather conditions. There are also links to be found between wind speed and
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89:
66:
361:
997:
332:
176:
73:, usually due to changes in temperature. Wind speed is now commonly measured with an
70:
898:
605:
581:
Hogan, C. Michael (2010). "Abiotic factor". In Emily
Monosson; C. Cleveland (eds.).
347:
recorded winds up to 150 metres per second (340 mph; 540 km/h) inside the
759:
460:
439:
221:. These operate on a global scale and move from west to east (hence being known as
140:(ICAO) also recommends meters per second for reporting wind speed when approaching
133:
121:
247:
as freak weather conditions can drastically affect the flow velocity of the wind.
534:
200:
160:
784:
549:
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276:
208:
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for reporting wind speeds, and used amongst others in weather forecasts in the
101:
911:
992:
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336:
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Lyza, Anthony W.; Flournoy, Matthew D.; Alford, A. Addison (19 March 2024).
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93:
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Another tool used to measure wind velocity includes a GPS combined with
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to measure the wind speeds remotely. Using this method, a mobile radar (
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236:
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184:
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62:
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31:
850:"5400mph winds discovered hurtling around planet outside solar system"
802:"Highest surface wind speed-Tropical Cyclone Olivia sets world record"
368:
292:
288:
665:. World Meteorological Association. 5 November 2015. Archived from
356:
244:
204:
85:
835:
371:. Scientists at the University of Warwick in 2015 determined that
328:
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272:
240:
125:
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is primarily used to determine the air velocity of an aircraft.
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340:
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play a key role in influencing wind speed, as the formation of
141:
100:
rates of many plant species, and countless other implications.
259:
The original anemometer that measured The Big Wind in 1934 at
191:, notably with the pressure gradient and terrain conditions.
948:
NBC 2005 Structural
Commentaries – Part 4 of Div. B, Comm. I
38:
55:
327:
Wind speeds within certain atmospheric phenomena (such as
448:
Anemometer on an outdoor stage set, to measure wind speed
501:(promulgator of ASCE 7-05, current version is ASCE 7-16)
16:
Rate at which air moves from high- to low-pressure areas
651:. Australian Meteorological and Oceanographic Journal.
796:
794:
108:(and not perpendicular, as one might expect), due to
834:. Center for Severe Weather Research. Archived from
525:
ICAO recommendations – International System of Units
957:
ASCE 7-05 commentary Figure C6-4, ASCE 7-10 C26.5-1
711:"Massive Okla. tornado had windspeed up to 200 mph"
875:"Make and Use an Anemometer to measure Wind Speed"
791:
735:
899:https://www.explainthatstuff.com/anemometers.html
394:Modern day anemometer used to capture wind speed.
275:ever recorded was during the passage of Tropical
144:, replacing their former recommendation of using
984:
589:National Council for Science and the Environment
748:National Oceanic and Atmospheric Administration
170:
729:
128:for velocity and the unit recommended by the
151:For historical reasons, other units such as
606:Windspeed | Icelandic Meteorological office
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638:
138:International Civil Aviation Organization
897:Chris Woodford. Ultrasonic anemometers.
443:
397:
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254:
37:
25:
635:
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34:is commonly used to measure wind speed.
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826:
271:The fastest wind speed not related to
580:
570:https://doi.org/10.5194/essd-2022-212
364:are not considered official records.
689:"The story of the world record wind"
499:American Society of Civil Engineers
300:was embedded in the already-strong
65:quantity caused by air moving from
13:
426:. A fluid flow velocity tool, the
367:Wind speeds can be much higher on
14:
1024:
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466:is calculated using the equation
130:World Meteorological Organization
970:
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309:Mount Washington (New Hampshire)
250:
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942:
917:
903:
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842:
820:
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756:American Meteorological Society
353:1999 Bridge Creek–Moore tornado
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691:. Mount Washington Observatory
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655:
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611:
599:
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540:Saffir–Simpson Hurricane Scale
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319:and confirmed to be accurate.
217:are strong winds in the upper
104:is usually almost parallel to
1:
630:Measuring Wind Speed in Knots
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343:) owned and operated by the
261:Mount Washington Observatory
171:Factors affecting wind speed
7:
787:. National Weather Service.
519:International Building Code
492:
322:
10:
1029:
437:
383:
18:
1013:Weather extremes of Earth
1003:Meteorological quantities
521:(promulgator of NBC 2005)
281:automatic weather station
663:"World record wind gust"
233:Local weather conditions
115:
19:Not to be confused with
764:10.1175/MWR-D-23-0242.1
481:is the air density and
317:National Weather Bureau
291:, registered a maximum
785:"Historical Tornadoes"
752:University of Oklahoma
743:Monthly Weather Review
449:
417:ultrasonic transducers
403:
395:
345:University of Oklahoma
263:
43:
35:
925:"Wind and Structures"
912:U.S. patent 5,877,416
584:Encyclopedia of Earth
514:Enhanced Fujita Scale
447:
401:
393:
362:Doppler weather radar
279:on 10 April 1996: an
258:
96:projects, growth and
41:
29:
979:at Wikimedia Commons
806:World Record Academy
669:on December 18, 2023
434:Design of structures
349:2013 El Reno tornado
832:"Doppler On Wheels"
587:. Washington D.C.:
485:is the wind speed.
313:hot-wire anemometer
146:kilometers per hour
82:weather forecasting
80:Wind speed affects
61:, is a fundamental
450:
404:
396:
264:
207:, also influences
199:combined with the
44:
36:
975:Media related to
808:. 26 January 2010
333:Doppler on Wheels
196:Pressure gradient
177:pressure gradient
136:. Since 2010 the
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591:. Archived from
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440:Wind engineering
304:of the cyclone.
134:Nordic countries
122:meter per second
110:Earth's rotation
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535:Prevailing wind
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201:Coriolis effect
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161:feet per second
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965:External links
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873:Koen, Joshua.
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838:on 2011-07-19.
828:Wurman, Joshua
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595:on 2013-06-08.
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550:Wind direction
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505:Beaufort scale
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438:Main article:
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384:Main article:
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337:Doppler radars
324:
321:
277:Cyclone Olivia
268:
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209:wind direction
189:wind direction
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165:Beaufort scale
153:miles per hour
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102:Wind direction
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717:. 20 May 2013
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933:. Retrieved
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882:. Retrieved
878:
868:
857:. Retrieved
853:
844:
836:the original
822:
810:. Retrieved
805:
779:
767:. Retrieved
741:
731:
719:. Retrieved
714:
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693:. Retrieved
683:
671:. Retrieved
667:the original
657:
625:
613:
601:
593:the original
583:
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510:Fujita scale
487:
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270:
267:Non-tornadic
232:
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215:Rossby waves
214:
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195:
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181:Rossby waves
174:
150:
119:
94:construction
92:operations,
79:
71:low pressure
51:
45:
931:(in Korean)
673:12 February
545:TORRO scale
530:Knot (unit)
380:Measurement
227:troposphere
219:troposphere
185:jet streams
63:atmospheric
48:meteorology
1008:Wind power
987:Categories
977:Wind speed
935:2018-04-18
884:2018-04-18
859:2020-08-08
695:26 January
556:References
428:Pitot tube
424:pitot tube
386:Anemometer
373:HD 189733b
369:exoplanets
335:or mobile
298:mesovortex
237:hurricanes
223:westerlies
159:(kn), and
98:metabolism
75:anemometer
59:flow speed
52:wind speed
32:anemometer
329:tornadoes
293:wind gust
289:Australia
273:tornadoes
998:Airspeed
830:(2007).
769:19 March
754:via the
715:CBS News
619:Aviation
493:See also
477:, where
357:Oklahoma
323:Tornadic
245:cyclones
241:monsoons
205:friction
148:(km/h).
90:maritime
86:aviation
21:Airspeed
473:ρv
302:eyewall
155:(mph),
142:runways
126:SI unit
106:isobars
812:17 May
721:17 May
479:ρ
341:RaXPol
243:, and
649:(PDF)
157:knots
116:Units
54:, or
993:Wind
814:2014
771:2024
750:and
723:2014
697:2010
675:2017
512:and
203:and
194:The
120:The
88:and
67:high
56:wind
760:doi
475:/ 2
355:in
283:on
69:to
46:In
30:An
989::
927:.
877:.
852:.
804:.
793:^
758:.
746:.
740:.
713:.
637:^
471:=
287:,
239:,
229:.
211:.
183:,
179:,
112:.
84:,
77:.
50:,
938:.
887:.
862:.
816:.
773:.
762::
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699:.
677:.
483:v
469:q
464:q
23:.
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