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Doppler on Wheels

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DOW 7 on display at the USA Science and Engineering Festival in 2010.

A Doppler on Wheels unit (DOW 3) observing a tornado near Attica, Kansas
Data gathered by a Doppler on Wheels unit showing a tornado near La Grange, Wyoming

Doppler on Wheels (or DOW) is a fleet of X-band and C-band mobile and quickly-deployable truck-borne radars which are the core instrumentation of the Flexible Array of Radars and Mesonets[1] affiliated with the University of Illinois[2] and led by Joshua Wurman, with the funding partially provided by the National Science Foundation (NSF), as part of the "Community Instruments and Facilities," (CIF) program. The DOW fleet and its associated Mobile Mesonets and deployable weather stations (PODs & Polenet) have been used throughout the United States since 1995, as well as occasionally in Europe and Southern America.[1] The Doppler on Wheels network has deployed itself through hazardous and challenging weather to gather data and information that may be missed by conventional stationary radar systems.

History[edit]

The first DOW platform was created and deployed in 1995, substantially changing the design paradigm of targeted meteorological studies. Ground-breaking, extremely fine-scale data was collected in tornadoes[3] and hurricanes,[4] as well as other phenomena. DOWs, by virtue of providing especially fine-scale targeted observations, have been central to various scientific discoveries, "firsts", and pioneering observations, e.g. the first concrete documentation of specific impacts of weather modification cloud seeding, the first mapping of multiple-vortices in tornadoes, the quantification of tornado low-level wind structure, etc. The DOW program rapidly expanded and evolved to include the first mobile dual-Doppler radar network, the first mobile rapid-scan radar (the Rapid-Scan DOW, RSDOW),[1] and the first quickly-deployable 1-degree C-band radar, the C-band on Wheels (COW). The DOWs, Mobile Mesonets, PODs & POLEs, as well as many other devices were crucial for instrumentation in numerous field projects, including VORTEX, VORTEX2, COPS, MAP, ASCII, IHOP, SCMS, CASES, ROTATE, PAMREX, SNOWD-UNDER, FLATLAND, HERO, UIDOW, UNDEO[citation needed], LEE, PERILS,[5] WINTRE-MIX,[6] RELAMPAGO,[7] GRAINEX,[8] and others.

In late 2018, the DOW Facility debuted a new quickly-deployable C-band radar (or COW) featuring a larger antenna and 5cm wavelength (as compared to the 3cm wavelength of the DOWs). Due to the larger size of the antenna, the truck features a built-in crane allowing for the radar to be assembled on site. The COW was first deployed as part of the RELAMPAGO field campaign in Argentina in late 2018.[9]

The DOW fleet has collected data in 250 tornadoes and inside the cores of eighteen hurricanes. DOWs have been deployed to Europe twice,[10] for the MAP and COPS field programs, and to Alaska twice for the JAWS-Juneau projects, and to South America for RELAMPAGO. DOWs have operated as high as 12,700 feet (3,900 m) on Bristol Head and at 10,000 feet (3,000 m) for the ASCII project at Battle Pass.

Capabilities[edit]

As of May 2024, the current operational Doppler on Wheels vehicles include the CROW (which consists of the DOW8/RSDOW/Mini-COW)[11], and the COW (C-band On Wheels, also known as the COW1).

The COW consists of a C-band dual-polarization dual-frequency radar system utilizing two 1 MW transmitters set to a 5cm wavelength configuration.[12] The CROW consists of three separate configurations, the DOW8, which utilizes a single-polarization 250 KW X-band transmitter, the RSDOW, which consists of a 7-second rapid-scan passive phased array antenna, utilizing a TWT 40 KW X-band transmitter system,[13] and the Mini-COW, utilizing a singular 1 MW C-band transmitter capable of 50-second dual-polarization updates.[11]

As of May 2024, the DOW6 and DOW7 are currently undergoing overhauls with new equipment, including the vehicles themselves, the transmitters, and the computing systems, as well as the integration with the new GURU software.[11] The previous iterations of the DOW6 and DOW7 utilized dual-polarization dual-frequency 250 KW X-band transmitters, and were the most powerful mobile X-band systems at the time.

DOWs are frequently deployed with the tightly integrated surface instrumentation network of the FARM.[12] Several instrumented mobile mesonet pickup trucks host in situ weather instrumentation on 3.5-metre (11 ft) masts to complement the remote sensing radars. These mobile mesonets also carry approximately twenty instrumented "PODS", which are ruggedized quickly deployable weather stations designed to survive inside tornadoes, tropical cyclones, and other adverse environments, and a Polenet comprising instrumentation deployed on poles, railings, fences, etc. during hurricane landfalls. An array of up to seven upper air and swarm sounding systems can also be deployed with the DOWs. The DOW fleet is sometimes accompanied by a Mobile Operations and Repair Center (MORC), a large van containing workstations for in-field coordination, data management, and equipment repair.[14]

Findings[edit]

DOW data led to the discovery of sub-kilometer hurricane boundary layer rolls, which likely modulate wind damage and may play a key role in hurricane intensification. DOW data revealed the most intense winds ever recorded (Bridge Creek–Moore tornado, 3 May 1999, or Greenfield tornado, 21 May 2024),[15][16] and the largest tornadic circulation ever documented (also 3 May 1999 in Mulhall, Oklahoma),[17] and made the first 3D maps of tornado winds and sub-tornadic vortex winds, and documented intense vortices within lake-effect snow bands. About 70 peer reviewed scientific publications have used DOW data.[citation needed]

The DOW fleet, PODS, and mobile mesonets have been featured on television, including Discovery Channel's reality series Storm Chasers,[18] National Geographic Channel's specials Tornado Intercept and The True Face of Hurricanes, and PBS's Nova episode "The Hunt for the Supertwister," and others.[citation needed]

DOW data has led to the discovery of the descending reflectivity core, a microscale phenomenon that may aid in tornadogenesis.

Future instrumentation[edit]

There are currently two major projects planned to expand the FARM's capabilities. The first is the creation of an S-band on Wheels Network (SOWNET) featuring four quickly-deployable S-band radars with 10 cm wavelengths capable of seeing through intense precipitation. These smaller truck-mounted radars would replace a single large S-band radar, allowing for dual-Doppler analyses and quicker deployment times. The second planned project is the Bistatic Adaptable Radar Network (BARN) which will be integrated with existing DOWs and the COW to provide high resolution wind vector observations without the need for multiple, expensive transmitters. These bistatic receivers will consist of small antennas that can be deployed like Pods or mounted onto a Mobile Mesonet or similar vehicle.[19]

See also[edit]

References[edit]

  1. ^ a b c "FARM: The DOW Network". farm.atmos.illinois.edu. Retrieved 25 April 2024.
  2. ^ "Home | Department of Climate, Meteorology & Atmospheric Sciences | Illinois". atmos.illinois.edu. Retrieved 25 April 2024.
  3. ^ Wurman, Joshua; Straka, Jerry M.; Rasmussen, Erik N. (1996). "Fine-Scale Doppler Radar Observations of Tornadoes". Science. 272 (5269): 1774–1777. Bibcode:1996Sci...272.1774W. doi:10.1126/science.272.5269.1774. PMID 8662481.
  4. ^ Wurman, Joshua; Winslow, Jennifer (1998). "Intense Sub-Kilometer-Scale Boundary Layer Rolls Observed in Hurricane Fran". Science. 280 (5363): 555–557. Bibcode:1998Sci...280..555W. doi:10.1126/science.280.5363.555. PMID 9554839.
  5. ^ "Next-generation storm forecasting project aims to save lives". NSF - National Science Foundation. 8 February 2023.
  6. ^ [1]
  7. ^ Nesbitt, Stephen W.; et al. (2021). "A Storm Safari in Subtropical South America: Proyecto RELAMPAGO". Bulletin of the American Meteorological Society. 102 (8): E1621–E1644. Bibcode:2021BAMS..102E1621N. doi:10.1175/BAMS-D-20-0029.1.
  8. ^ [2]
  9. ^ Reppenhagen, Cory (4 December 2018). "New Colorado-designed 'Doppler on Wheels' chasing storms in Argentina". KUSA. Retrieved 3 May 2022. Atmospheric scientists are excited about a new radar making its debut in Argentina. It's a Doppler on Wheels (DOW) built by the Center for Severe Weather Research in Boulder. [...] It is part of the RELAMPAGO project, studying severe storms in the Cordoba region of Argentina. A place where scientists believe some of the most intense storms on the planet form.
  10. ^ Kouhestani, Jeanne; McGehan, Barbara; Tarp, Keli (14 October 1999). "NOAA SCIENTISTS, RESEARCH AIRCRAFT AND DOPPLER LIDAR JOIN MASSIVE WEATHER RESEARCH STUDY IN EUROPE" (Press Release). Archived from the original on 11 December 2016. Retrieved 3 May 2022. Scientists, a Doppler lidar, and a "hurricane hunter" aircraft from the National Oceanic and Atmospheric Administration have joined the largest weather research project ever conducted in Europe to study the effects on weather of wind flow over the Alps. Researchers from 11 nations hope to gain a better understanding of how this wind affects the weather, and to improve weather and river forecast models for mountainous areas, NOAA said today.
  11. ^ a b c "FARM Updated Capabilities (including fully mobile mini-COW) 2023 AMS" (PDF). Retrieved 6 May 2024.
  12. ^ a b Wurman, Joshua; Kosiba, Karen; Pereira, Brian; Robinson, Paul; Frambach, Andrew; Gilliland, Alycia; White, Trevor; Aikins, Josh; Trapp, Robert J.; Nesbitt, Stephen; Hanshaw, Maiana N.; Lutz, Jon (2021). "The Flexible Array of Radars and Mesonets (FARM)". Bulletin of the American Meteorological Society. 102 (8): E1499–E1525. Bibcode:2021BAMS..102E1499W. doi:10.1175/BAMS-D-20-0285.1.
  13. ^ "FARM: The DOW Network". farm.atmos.illinois.edu. Retrieved 6 May 2024.
  14. ^ "Observation". NOAA National Severe Storms Laboratory.
  15. ^ Williams, Jack (17 May 2005). "Doppler radar measures 318 mph wind in tornado". USA Today. ISSN 0734-7456. LCCN sn82006685. OCLC 819006199. Archived from the original on 16 October 2012. Retrieved 3 May 2022. Scientists measured the fastest wind speed ever recorded, 318 mph, in one of the tornadoes that hit the suburbs of Oklahoma City on May 3, 1999. [...] The record-setting wind occurred about 7 p.m. near Moore, where the tornado killed four people and destroyed about 250 houses
  16. ^ "As the 2024 #BEST field season ends, a glimpse into the data collection during the Greenfield, IA tornado. Peak wind speeds as high as 309-318 mph were calculated in a narrow region 100-160 feet ARL. These are among the highest wind speeds ever determined using DOW data". x.com. University of Illinois. 22 June 2024. Retrieved 22 June 2024.
  17. ^ "Rapid-Scanning Doppler on Wheels Keeps Pace with Twisters - News Release". Archived from the original on 7 May 2013. Retrieved 2 February 2017.
  18. ^ "Doppler on Wheels | Storm Chasers | Discovery". Archived from the original on 21 April 2017. Retrieved 3 February 2017.
  19. ^ Wurman, Joshua; Kosiba, Karen (1 August 2021). "The Flexible Array of Radars and Mesonets (FARM)". Bulletin of the American Meteorological Society. 102 (8): E1499–E1525. Bibcode:2021BAMS..102E1499W. doi:10.1175/BAMS-D-20-0285.1. S2CID 234827910.

External links[edit]

Wikimedia Commons has media related to DOW (radar).
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