TWISTEX
Encyclopedia
TWISTEX is a tornado
research experiment headed up by Tim Samaras from Denver, Colorado
. The project normally runs from mid-April through the end of June with a domain that covers the Great Plains
and portions of the Midwest. The project is normally at full strength for most of May and June with four vehicles, all equipped with roof-mounted mobile mesonet weather stations. One of the vehicles transports an array of in situ thermodynamic and video probes. Due to graduate and upper-division undergraduate student participant availability, a reduced vehicle compliment consisting of the in situ probe deployment truck and one support mesonet station vehicle is used in the first few weeks of the project.
The objectives of this research are to better understand tornado generation, maintenance and decay processes and to gain insight and knowledge of the seldom sampled near-surface internal tornado environment. Progress on these research fronts is aimed toward increasing tornado warning lead time while the internal tornado near-surface sampling provides essential ground truth data for structural engineering analysis of the interaction of tornadic winds with homes and buildings.
TWISTEX is one of the featured teams in seasons 3 and 4 of Storm Chasers on the Discovery Channel
. The group has also been featured on National Geographic Channel
's "Disaster Labs".
Students from the Atmospheric Sciences Department at Iowa State University
rotate shifts into the mesonet vehicles during the project.
The thermodynamic probes are called Hardened In-situ Tornado Pressure Recorders (HITPR). All of the hardened instrumentation can collect/store the datasets. Measurements are recorded at 10 samples/second, and stored on non-volatile flash cards.
TWISTEX will also have video probes that will provide visualization using 7 cameras each for a total of 14 cameras being deployed into the tornado core. Collectively the two camera probes will be used for photogrammetry purposes to visualize/measure tornado-driven debris and hydrometeors as well as for determining the tornado-relative location of the HITPRs.
New additional technologies will be used by deployment crew members to collect photogrammetric data from tornadoes as close as possible. One technique will be to record close tornado imagery using two digitally synchronized high-resolution high-speed cameras running at 500 frames per second for stereo photogrammetry techniques. This technique will provide excellent time resolution for velocity determination of low-level tornado core winds and lofted debris.
Each of the participating TWISTEX vehicles will have a mobile mesonet (MM) station mounted on the roof including the probe deployment truck. The mobile mesonet will be attempting to gather near-surface thermodynamic and kinematic data in as many quadrants of the RFD as possible. When coupled with the in-situ probe array data which represents another effective mesonet station, it is hoped to obtain thermodynamic and kinematic mapping that will describe characteristics of the flow reaching the tornado. Even if the hardened tornado probes do not take a direct hit, a peripheral tornado sampling is still very worthwhile.
AMS Journal and Conference Papers
Lee, B. D., C. A. Finley, and T. M. Samaras, 2011: Surface analysis near and within the Tipton, Kansas, tornado on 29 May 2008. Mon. Wea. Rev., 139, 370-386.
http://journals.ametsoc.org/doi/abs/10.1175/2010MWR3454.1
Karstens, C. D., T. M. Samaras, B. D. Lee, W. A. Gallus, and C. A. Finley, 2010: Near-ground pressure and wind measurements in tornadoes. Mon. Wea. Rev., 138, 2570-2588.
http://journals.ametsoc.org/doi/pdf/10.1175/2010MWR3201.1
Finley, C. A., B. D. Lee, M. Grzych, C. D. Karstens, and T. M. Samaras, 2010: Mobile mesonet observations of the rear-flank downdraft evolution associated with a violent tornado near Bowdle, SD on 22 May 2010. Electronic proceedings, 25th Conf. on Severe Local Storms, Denver, CO. Amer. Meteor. Soc., 8A.2.
http://ams.confex.com/ams/pdfpapers/176132.pdf
Karstens, C. D., T. M. Samaras, W. A. Gallus, C. A. Finley, B. D. Lee 2010: Analysis of near-surface wind flow in close proximity to tornadoes. Electronic proceedings, 25th Conf. on Severe Local Storms, Denver, CO. Amer. Meteor. Soc., P10.11.
http://ams.confex.com/ams/pdfpapers/176188.pdf
Lee, B. D., C. A. Finley, C. D. Karstens, and T. M. Samaras, 2010: Surface observations of the rear-flank downdraft evolution associated with the Aurora, NE tornado of 17 June 2009. Electronic proceedings, 25th Conf. on Severe Local Storms, Denver, CO. Amer. Meteor. Soc., P8.27.
http://ams.confex.com/ams/pdfpapers/176133.pdf
Finley, C. A., and B. D. Lee, 2008: Mobile mesonet observations of an Intense RFD and multiple gust fronts in the May 23 Quinter, Kansas tornadic supercell during TWISTEX 2008. Electronic proceedings, 24th Conf. on Severe Local Storms, Savannah, GA Amer. Meteor. Soc., P3.18.
http://ams.confex.com/ams/pdfpapers/142133.pdf
Karstens, C. D., T. M. Samaras, A. Laubach, B. D. Lee, C. A. Finley, W. A. Gallus, F. L. Hann, 2008. TWISTEX 2008: In situ and mobile mesonet observations of tornadoes. Electronic proceedings, 24th Conf. on Severe Local Storms, Savannah, GA Amer. Meteor. Soc., P3.11.
http://ams.confex.com/ams/pdfpapers/141974.pdf
Lee, B.D., C. A. Finley, and T. M. Samaras, 2008: Thermodynamic and kinematic analysis near and within the Tipton, KS tornado on May 29 during TWISTEX 2008. Electronic proceedings, 24th Conf. on Severe Local Storms, Savannah, GA Amer. Meteor. Soc., P3.13.
http://ams.confex.com/ams/pdfpapers/142078.pdf
Grzych, M. L., B. D. Lee, and C. A. Finley, 2007: Thermodynamic analysis of supercell rear-flank downdrafts from Project ANSWERS. Mon. Wea. Rev., 135, 240-246.
http://ams.allenpress.com/perlserv/?request=get-pdf&doi=10.1175%2FMWR3288.1
Finley, C. A., and B. D. Lee, 2004: High resolution mobile mesonet observations of RFD surges in the June 9 Basset, Nebraska supercell during project answers 2003. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, CD-ROM, 11.3.
http://ams.confex.com/ams/pdfpapers/82005.pdf
Lee, B. D., C. A. Finley, and P. Skinner, 2004: Thermodynamic and kinematic analysis of multiple RFD surges for the 24 June 2003 Manchester, South Dakota cyclic tornadic supercell during Project ANSWERS 2003. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer. Meteor. Soc., CD-ROM, 11.2.
http://ams.confex.com/ams/pdfpapers/82000.pdf
Lee, J. J., T. M. Samaras, and C. R. Young, 2004: Pressure measurements at the ground in an F-4 tornaado. 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer, Meteor. Soc., CD_ROM, 15.3.
http://ams.confex.com/ams/pdfpapers/81700.pdf
Samaras, T. M., 2004: A historical perspective of in-situ observations within tornado cores. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer, Meteor. Soc., CD_ROM, P11.4.
http://ams.confex.com/ams/pdfpapers/81153.pdf
Samaras, T.M., and J. J. Lee, 2004. Pressure measurements within a large tornado. Proc. 84th American Meteorological Society Annual Meeting - Eighth Symposium on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface, Seattle, WA., P4.9.
http://ams.confex.com/ams/pdfpapers/74267.pdf
Wurman, J., and T. Samaras, 2004: Comparison of in-situ pressure and DOW Doppler winds in a tornado and RHI vertical slices through 4 tornadoes during 1996-2004. Extended Abstracts, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer. Meteor. Soc., 15.4, 1-14.
http://ams.confex.com/ams/pdfpapers/82352.pdf
National Geographic (Book and articles about Samaras research)
Tornado Hunter, by Stephen Bechtel with Tim Samaras. Published by National Geographic. pp. 272. Release May 19, 2009.
National Geographic in the Field - Tim Samaras, Severe-Storms Researcher (2005)
http://www.nationalgeographic.com/field/explorers/tim-samaras.html
National Geographic Feature - New View of Tornadoes: From the Inside Looking Out (2005)
http://www7.nationalgeographic.com/ngm/0506/feature6/index.html
National Geographic Events – Inside the Tornado (2005)
http://www.nationalgeographic.com/speakers/profile_samaras.html
National Geographic Today - Storm Chaser Deploys Probe, Makes History (2003)
http://news.nationalgeographic.com/news/2003/06/0627_030627_tvtornadochaser.html
American Society of Civil Engineers
Samaras, T. M., and J. J. Lee, 2006: Measuring tornado dynamics with in-situ instrumentation. Proceedings of the 2006 Structures Congress: 2006 Structural Engineering and Public Safety. St. Louis, Missouri, pp. 1-10, (doi 10.1061/40889(201)12).
http://cedb.asce.org/cgi/WWWdisplay.cgi?0609031
ABC News (Article about Samaras research)
World News - Scientists Put an Eye in the Heart of the Storm (2005)
http://abcnews.go.com/WNT/Science/story?id=831857
television programs.
This section may need updating
Disaster Lab – "Inside the Tornado", National Geographic Channel
(Aired May 14, 2009)
Storm Chasers - Ep. 1, Storm Catchers, The Discovery Channel (Aired October 18, 2009)
Storm Chasers - Ep. 2, Bigger In Texas, The Discovery Channel (Aired October 25, 2009)
Storm Chasers - Ep. 4, Inside The Tornado, The Discovery Channel (Aired November 8, 2009)
Storm Chasers - Ep. 5, Not In Kansas Anymore, The Discovery Channel (Aired November 15, 2009)
Storm Chasers - Ep. 6, Fight Or Flight, The Discovery Channel (Aired November 22, 2009)
Storm Chasers - Ep. 7, Sean Casey At The Bat, The Discovery Channel (Aired November 29, 2009)
Storm Chasers - Ep. 8, EF-3 Strikes You're Out, The Discovery Channel (Aired November 29, 2009)
Tornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
research experiment headed up by Tim Samaras from Denver, Colorado
Denver, Colorado
The City and County of Denver is the capital and the most populous city of the U.S. state of Colorado. Denver is a consolidated city-county, located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains...
. The project normally runs from mid-April through the end of June with a domain that covers the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
and portions of the Midwest. The project is normally at full strength for most of May and June with four vehicles, all equipped with roof-mounted mobile mesonet weather stations. One of the vehicles transports an array of in situ thermodynamic and video probes. Due to graduate and upper-division undergraduate student participant availability, a reduced vehicle compliment consisting of the in situ probe deployment truck and one support mesonet station vehicle is used in the first few weeks of the project.
The objectives of this research are to better understand tornado generation, maintenance and decay processes and to gain insight and knowledge of the seldom sampled near-surface internal tornado environment. Progress on these research fronts is aimed toward increasing tornado warning lead time while the internal tornado near-surface sampling provides essential ground truth data for structural engineering analysis of the interaction of tornadic winds with homes and buildings.
TWISTEX is one of the featured teams in seasons 3 and 4 of Storm Chasers on the Discovery Channel
Discovery Channel
Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...
. The group has also been featured on National Geographic Channel
National Geographic Channel
National Geographic Channel, also commercially abbreviated and trademarked as Nat Geo, is a subscription television channel that airs non-fiction television programs produced by the National Geographic Society. Like History and the Discovery Channel, the channel features documentaries with factual...
's "Disaster Labs".
TWISTEX personnel
- Tim Samaras; TWISTEX Director, Engineer
- Dr. Bruce Lee; Mobile Mesonet Director, Atmospheric Scientist
- Dr. Cathy Finley; Mobile Mesonet Co-Director, Atmospheric Scientist
- Chris Karstens; Mesonet Team Leader & Software Development, ISU Atmospheric Sciences Ph.D. Student
- Matt Grzych; Software & Systems Development, Atmospheric Scientist
- Tony LaubachTony LaubachTony Laubach is an American professional storm chaser and Meteorologist. He has participated in several field research projects, been contracted as a severe weather photojournalist for several major television networks, starred in several television shows, including Seasons 3 and 4 of "Storm...
; Mesonet Team Leader & Video Archival/Production, Meteorologist - Carl Young; Probe Driver, Meteorologist
- Ed Grubb; Mobile Mesonet Navigator, Mechanical Guru
- Paul Samaras; Photographer
Students from the Atmospheric Sciences Department at Iowa State University
Iowa State University
Iowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...
rotate shifts into the mesonet vehicles during the project.
Tornado Core Sampling
Several hardened instruments will be deployed in paths of tornadoes to collect the following datasets:- Pressure
- Temperature
- Humidity
- Wind speed/direction
- Visualization for accurate debris/hydrometeor velocities and for verification of the tornado-relative location of the in situ sampling
The thermodynamic probes are called Hardened In-situ Tornado Pressure Recorders (HITPR). All of the hardened instrumentation can collect/store the datasets. Measurements are recorded at 10 samples/second, and stored on non-volatile flash cards.
TWISTEX will also have video probes that will provide visualization using 7 cameras each for a total of 14 cameras being deployed into the tornado core. Collectively the two camera probes will be used for photogrammetry purposes to visualize/measure tornado-driven debris and hydrometeors as well as for determining the tornado-relative location of the HITPRs.
New additional technologies will be used by deployment crew members to collect photogrammetric data from tornadoes as close as possible. One technique will be to record close tornado imagery using two digitally synchronized high-resolution high-speed cameras running at 500 frames per second for stereo photogrammetry techniques. This technique will provide excellent time resolution for velocity determination of low-level tornado core winds and lofted debris.
Tornado Proximity Environment Sampling
While there are abundant kinematic datasets gathered by mobile radar of the tornadic region of supercells, the number of quality mobile mesonet or sticknet thermodynamic datasets of the flow field proximate to the tornadic region, generally within the supercell rear-flank downdraft (RFD) outflow, are comparatively rare. Even rarer are mesonet datasets reaching within about 1.5 km of tornadoes and datasets sampling the thermodynamic evolution of the RFD outflow.Each of the participating TWISTEX vehicles will have a mobile mesonet (MM) station mounted on the roof including the probe deployment truck. The mobile mesonet will be attempting to gather near-surface thermodynamic and kinematic data in as many quadrants of the RFD as possible. When coupled with the in-situ probe array data which represents another effective mesonet station, it is hoped to obtain thermodynamic and kinematic mapping that will describe characteristics of the flow reaching the tornado. Even if the hardened tornado probes do not take a direct hit, a peripheral tornado sampling is still very worthwhile.
TWISTEX publications
Participants of the TWISTEX research project have contributed to many publications.AMS Journal and Conference Papers
Lee, B. D., C. A. Finley, and T. M. Samaras, 2011: Surface analysis near and within the Tipton, Kansas, tornado on 29 May 2008. Mon. Wea. Rev., 139, 370-386.
http://journals.ametsoc.org/doi/abs/10.1175/2010MWR3454.1
Karstens, C. D., T. M. Samaras, B. D. Lee, W. A. Gallus, and C. A. Finley, 2010: Near-ground pressure and wind measurements in tornadoes. Mon. Wea. Rev., 138, 2570-2588.
http://journals.ametsoc.org/doi/pdf/10.1175/2010MWR3201.1
Finley, C. A., B. D. Lee, M. Grzych, C. D. Karstens, and T. M. Samaras, 2010: Mobile mesonet observations of the rear-flank downdraft evolution associated with a violent tornado near Bowdle, SD on 22 May 2010. Electronic proceedings, 25th Conf. on Severe Local Storms, Denver, CO. Amer. Meteor. Soc., 8A.2.
http://ams.confex.com/ams/pdfpapers/176132.pdf
Karstens, C. D., T. M. Samaras, W. A. Gallus, C. A. Finley, B. D. Lee 2010: Analysis of near-surface wind flow in close proximity to tornadoes. Electronic proceedings, 25th Conf. on Severe Local Storms, Denver, CO. Amer. Meteor. Soc., P10.11.
http://ams.confex.com/ams/pdfpapers/176188.pdf
Lee, B. D., C. A. Finley, C. D. Karstens, and T. M. Samaras, 2010: Surface observations of the rear-flank downdraft evolution associated with the Aurora, NE tornado of 17 June 2009. Electronic proceedings, 25th Conf. on Severe Local Storms, Denver, CO. Amer. Meteor. Soc., P8.27.
http://ams.confex.com/ams/pdfpapers/176133.pdf
Finley, C. A., and B. D. Lee, 2008: Mobile mesonet observations of an Intense RFD and multiple gust fronts in the May 23 Quinter, Kansas tornadic supercell during TWISTEX 2008. Electronic proceedings, 24th Conf. on Severe Local Storms, Savannah, GA Amer. Meteor. Soc., P3.18.
http://ams.confex.com/ams/pdfpapers/142133.pdf
Karstens, C. D., T. M. Samaras, A. Laubach, B. D. Lee, C. A. Finley, W. A. Gallus, F. L. Hann, 2008. TWISTEX 2008: In situ and mobile mesonet observations of tornadoes. Electronic proceedings, 24th Conf. on Severe Local Storms, Savannah, GA Amer. Meteor. Soc., P3.11.
http://ams.confex.com/ams/pdfpapers/141974.pdf
Lee, B.D., C. A. Finley, and T. M. Samaras, 2008: Thermodynamic and kinematic analysis near and within the Tipton, KS tornado on May 29 during TWISTEX 2008. Electronic proceedings, 24th Conf. on Severe Local Storms, Savannah, GA Amer. Meteor. Soc., P3.13.
http://ams.confex.com/ams/pdfpapers/142078.pdf
Grzych, M. L., B. D. Lee, and C. A. Finley, 2007: Thermodynamic analysis of supercell rear-flank downdrafts from Project ANSWERS. Mon. Wea. Rev., 135, 240-246.
http://ams.allenpress.com/perlserv/?request=get-pdf&doi=10.1175%2FMWR3288.1
Finley, C. A., and B. D. Lee, 2004: High resolution mobile mesonet observations of RFD surges in the June 9 Basset, Nebraska supercell during project answers 2003. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, CD-ROM, 11.3.
http://ams.confex.com/ams/pdfpapers/82005.pdf
Lee, B. D., C. A. Finley, and P. Skinner, 2004: Thermodynamic and kinematic analysis of multiple RFD surges for the 24 June 2003 Manchester, South Dakota cyclic tornadic supercell during Project ANSWERS 2003. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer. Meteor. Soc., CD-ROM, 11.2.
http://ams.confex.com/ams/pdfpapers/82000.pdf
Lee, J. J., T. M. Samaras, and C. R. Young, 2004: Pressure measurements at the ground in an F-4 tornaado. 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer, Meteor. Soc., CD_ROM, 15.3.
http://ams.confex.com/ams/pdfpapers/81700.pdf
Samaras, T. M., 2004: A historical perspective of in-situ observations within tornado cores. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer, Meteor. Soc., CD_ROM, P11.4.
http://ams.confex.com/ams/pdfpapers/81153.pdf
Samaras, T.M., and J. J. Lee, 2004. Pressure measurements within a large tornado. Proc. 84th American Meteorological Society Annual Meeting - Eighth Symposium on Integrated Observing and Assimilation Systems for Atmosphere, Oceans, and Land Surface, Seattle, WA., P4.9.
http://ams.confex.com/ams/pdfpapers/74267.pdf
Wurman, J., and T. Samaras, 2004: Comparison of in-situ pressure and DOW Doppler winds in a tornado and RHI vertical slices through 4 tornadoes during 1996-2004. Extended Abstracts, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer. Meteor. Soc., 15.4, 1-14.
http://ams.confex.com/ams/pdfpapers/82352.pdf
National Geographic (Book and articles about Samaras research)
Tornado Hunter, by Stephen Bechtel with Tim Samaras. Published by National Geographic. pp. 272. Release May 19, 2009.
National Geographic in the Field - Tim Samaras, Severe-Storms Researcher (2005)
http://www.nationalgeographic.com/field/explorers/tim-samaras.html
National Geographic Feature - New View of Tornadoes: From the Inside Looking Out (2005)
http://www7.nationalgeographic.com/ngm/0506/feature6/index.html
National Geographic Events – Inside the Tornado (2005)
http://www.nationalgeographic.com/speakers/profile_samaras.html
National Geographic Today - Storm Chaser Deploys Probe, Makes History (2003)
http://news.nationalgeographic.com/news/2003/06/0627_030627_tvtornadochaser.html
American Society of Civil Engineers
Samaras, T. M., and J. J. Lee, 2006: Measuring tornado dynamics with in-situ instrumentation. Proceedings of the 2006 Structures Congress: 2006 Structural Engineering and Public Safety. St. Louis, Missouri, pp. 1-10, (doi 10.1061/40889(201)12).
http://cedb.asce.org/cgi/WWWdisplay.cgi?0609031
ABC News (Article about Samaras research)
World News - Scientists Put an Eye in the Heart of the Storm (2005)
http://abcnews.go.com/WNT/Science/story?id=831857
TWISTEX on television
TWISTEX has been featured on the following documentaryDocumentary
A documentary is a creative work of non-fiction, including:* Documentary film, including television* Radio documentary* Documentary photographyRelated terms include:...
television programs.
This section may need updating
Disaster Lab – "Inside the Tornado", National Geographic Channel
National Geographic Channel
National Geographic Channel, also commercially abbreviated and trademarked as Nat Geo, is a subscription television channel that airs non-fiction television programs produced by the National Geographic Society. Like History and the Discovery Channel, the channel features documentaries with factual...
(Aired May 14, 2009)
Storm Chasers - Ep. 1, Storm Catchers, The Discovery Channel (Aired October 18, 2009)
Storm Chasers - Ep. 2, Bigger In Texas, The Discovery Channel (Aired October 25, 2009)
Storm Chasers - Ep. 4, Inside The Tornado, The Discovery Channel (Aired November 8, 2009)
Storm Chasers - Ep. 5, Not In Kansas Anymore, The Discovery Channel (Aired November 15, 2009)
Storm Chasers - Ep. 6, Fight Or Flight, The Discovery Channel (Aired November 22, 2009)
Storm Chasers - Ep. 7, Sean Casey At The Bat, The Discovery Channel (Aired November 29, 2009)
Storm Chasers - Ep. 8, EF-3 Strikes You're Out, The Discovery Channel (Aired November 29, 2009)