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Joshua Wurman - One of the best experts on this subject based on the ideXlab platform.
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Research Article Wind Field of a Nonmesocyclone Anticyclonic Tornado Crossing the Hong Kong International Airport
2016Co-Authors: Karen Kosiba, Paul Robinson, P. W. Chan, Joshua WurmanAbstract:Copyright © 2014 Karen A. Kosiba et al.This is an open access article distributed under theCreativeCommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A nonmesocyclone Tornado traversed the Hong Kong International Airport on September 6, 2004 directly impacting a surface weather station. This allowed for 1-second 10-meter above ground level (AGL) wind observations through the core of the Tornado. Integration of these 10-meter AGL wind data with Ground-Based Velocity Track (GBVTD) wind retrievals derived from LIDAR data provided a time history of the three-dimensional wind field of the Tornado. These data indicate a progressive decrease in radial inflow with time and little to no radial inflow near the time the Tornado crosses the surface weather station. Anemometer observations suggest that the tangential winds approximate a modified-Rankine vortex outside the radius of maximum winds, suggesting that frictionally induced radial inflow was confined below 10mAGL. The radial-height distribution of angular momentum depicts an increase in low-level angular momentum just prior to the Tornado reaching its maximum intensity. 1
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Wind Field of a Nonmesocyclone Anticyclonic Tornado Crossing the Hong Kong International Airport
Hindawi Limited, 2014Co-Authors: Karen Kosiba, Paul Robinson, P. W. Chan, Joshua WurmanAbstract:A nonmesocyclone Tornado traversed the Hong Kong International Airport on September 6, 2004 directly impacting a surface weather station. This allowed for 1-second 10-meter above ground level (AGL) wind observations through the core of the Tornado. Integration of these 10-meter AGL wind data with Ground-Based Velocity Track (GBVTD) wind retrievals derived from LIDAR data provided a time history of the three-dimensional wind field of the Tornado. These data indicate a progressive decrease in radial inflow with time and little to no radial inflow near the time the Tornado crosses the surface weather station. Anemometer observations suggest that the tangential winds approximate a modified-Rankine vortex outside the radius of maximum winds, suggesting that frictionally induced radial inflow was confined below 10 m AGL. The radial-height distribution of angular momentum depicts an increase in low-level angular momentum just prior to the Tornado reaching its maximum intensity
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in situ doppler radar and video observations of the interior structure of a Tornado and the wind damage relationship
Bulletin of the American Meteorological Society, 2012Co-Authors: Joshua Wurman, Karen Kosiba, Paul RobinsonAbstract:Direct observations of the winds inside a Tornado were obtained with an instrumented armored vehicle, the Tornado Intercept Vehicle (TIV), and integrated with finescale mobile Doppler radar (Doppler on Wheels) data revealing, for the first time, the structure of the near-ground three-dimensional wind field in and around the core region of a strong Tornado, and permitting comparison with conceptual models. Inward and upward spiraling near-surface flow, upward motion near the surface, and an axial downdraft aloft are documented, as well as a periodic oscillation in Tornado intensity. Simultaneous video documentation of damage occurring during the Tornado is related to the direct wind observations, permitting the first comparisons of the time history of damage to the time history of directly measured winds and a limited evaluation of the underlying assumptions and quantitative relationships in the enhanced Fujita (EF) scale.
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Tornado maintenance investigated with high-resolution Dual-Doppler and EnKF analysis
Monthly Weather Review, 2012Co-Authors: James Marquis, David C. Dowell, Yvette Richardson, Paul Markowski, Joshua WurmanAbstract:AbstractDual-Doppler wind synthesis and ensemble Kalman filter analyses produced by assimilating Doppler-on-Wheels velocity data collected in four tornadic supercells are examined in order to further understand the maintenance of Tornadoes. Although Tornado-scale features are not resolved in these analyses, larger-scale processes involved with Tornado maintenance are well represented.The longest-lived Tornado is maintained underneath the midlevel updraft within a zone of low-level horizontal convergence along a rear-flank gust front for a considerable time, and dissipates when horizontally displaced from the midlevel updraft. The shortest-lived Tornado resides in a similar zone of low-level convergence briefly, but dissipates underneath the location of the midlevel updraft when the updraft becomes tilted and low-level convergence is displaced several kilometers from the Tornado. This suggests that a location beneath the midlevel updraft is not always a sufficient condition for Tornado maintenance, particu...
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finescale single and dual doppler analysis of Tornado intensification maintenance and dissipation in the orleans nebraska supercell
Monthly Weather Review, 2010Co-Authors: Joshua Wurman, David C. Dowell, Yvette Richardson, Paul Markowski, Karen Kosiba, Paul RobinsonAbstract:Abstract Finescale single- and dual-Doppler observations are used to diagnose the three-dimensional structure of the wind field surrounding a Tornado that occurred near the town of Orleans, Nebraska, on 22 May 2004. The evolution of the vorticity and divergence fields and other structures near the Tornado are documented in the lowest kilometer. Changes in Tornado intensity are compared to the position of the Tornado relative to primary and secondary gust fronts. Circulation on scales of a few kilometers surrounding the Tornado remains relatively constant during the analysis period, which spans the intensifying and mature periods of the Tornado’s life cycle. Stretching of vertical vorticity and tilting of horizontal vorticity are diagnosed, but the latter is near or below the threshold of detectability in this analysis during the observation period in the analyzed domain. Low-level circulation within 500 m of the Tornado increased several minutes before vortex-relative and ground-relative near-surface wind...
Paul Robinson - One of the best experts on this subject based on the ideXlab platform.
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Research Article Wind Field of a Nonmesocyclone Anticyclonic Tornado Crossing the Hong Kong International Airport
2016Co-Authors: Karen Kosiba, Paul Robinson, P. W. Chan, Joshua WurmanAbstract:Copyright © 2014 Karen A. Kosiba et al.This is an open access article distributed under theCreativeCommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A nonmesocyclone Tornado traversed the Hong Kong International Airport on September 6, 2004 directly impacting a surface weather station. This allowed for 1-second 10-meter above ground level (AGL) wind observations through the core of the Tornado. Integration of these 10-meter AGL wind data with Ground-Based Velocity Track (GBVTD) wind retrievals derived from LIDAR data provided a time history of the three-dimensional wind field of the Tornado. These data indicate a progressive decrease in radial inflow with time and little to no radial inflow near the time the Tornado crosses the surface weather station. Anemometer observations suggest that the tangential winds approximate a modified-Rankine vortex outside the radius of maximum winds, suggesting that frictionally induced radial inflow was confined below 10mAGL. The radial-height distribution of angular momentum depicts an increase in low-level angular momentum just prior to the Tornado reaching its maximum intensity. 1
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Wind Field of a Nonmesocyclone Anticyclonic Tornado Crossing the Hong Kong International Airport
Hindawi Limited, 2014Co-Authors: Karen Kosiba, Paul Robinson, P. W. Chan, Joshua WurmanAbstract:A nonmesocyclone Tornado traversed the Hong Kong International Airport on September 6, 2004 directly impacting a surface weather station. This allowed for 1-second 10-meter above ground level (AGL) wind observations through the core of the Tornado. Integration of these 10-meter AGL wind data with Ground-Based Velocity Track (GBVTD) wind retrievals derived from LIDAR data provided a time history of the three-dimensional wind field of the Tornado. These data indicate a progressive decrease in radial inflow with time and little to no radial inflow near the time the Tornado crosses the surface weather station. Anemometer observations suggest that the tangential winds approximate a modified-Rankine vortex outside the radius of maximum winds, suggesting that frictionally induced radial inflow was confined below 10 m AGL. The radial-height distribution of angular momentum depicts an increase in low-level angular momentum just prior to the Tornado reaching its maximum intensity
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in situ doppler radar and video observations of the interior structure of a Tornado and the wind damage relationship
Bulletin of the American Meteorological Society, 2012Co-Authors: Joshua Wurman, Karen Kosiba, Paul RobinsonAbstract:Direct observations of the winds inside a Tornado were obtained with an instrumented armored vehicle, the Tornado Intercept Vehicle (TIV), and integrated with finescale mobile Doppler radar (Doppler on Wheels) data revealing, for the first time, the structure of the near-ground three-dimensional wind field in and around the core region of a strong Tornado, and permitting comparison with conceptual models. Inward and upward spiraling near-surface flow, upward motion near the surface, and an axial downdraft aloft are documented, as well as a periodic oscillation in Tornado intensity. Simultaneous video documentation of damage occurring during the Tornado is related to the direct wind observations, permitting the first comparisons of the time history of damage to the time history of directly measured winds and a limited evaluation of the underlying assumptions and quantitative relationships in the enhanced Fujita (EF) scale.
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finescale single and dual doppler analysis of Tornado intensification maintenance and dissipation in the orleans nebraska supercell
Monthly Weather Review, 2010Co-Authors: Joshua Wurman, David C. Dowell, Yvette Richardson, Paul Markowski, Karen Kosiba, Paul RobinsonAbstract:Abstract Finescale single- and dual-Doppler observations are used to diagnose the three-dimensional structure of the wind field surrounding a Tornado that occurred near the town of Orleans, Nebraska, on 22 May 2004. The evolution of the vorticity and divergence fields and other structures near the Tornado are documented in the lowest kilometer. Changes in Tornado intensity are compared to the position of the Tornado relative to primary and secondary gust fronts. Circulation on scales of a few kilometers surrounding the Tornado remains relatively constant during the analysis period, which spans the intensifying and mature periods of the Tornado’s life cycle. Stretching of vertical vorticity and tilting of horizontal vorticity are diagnosed, but the latter is near or below the threshold of detectability in this analysis during the observation period in the analyzed domain. Low-level circulation within 500 m of the Tornado increased several minutes before vortex-relative and ground-relative near-surface wind...
Karen Kosiba - One of the best experts on this subject based on the ideXlab platform.
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Research Article Wind Field of a Nonmesocyclone Anticyclonic Tornado Crossing the Hong Kong International Airport
2016Co-Authors: Karen Kosiba, Paul Robinson, P. W. Chan, Joshua WurmanAbstract:Copyright © 2014 Karen A. Kosiba et al.This is an open access article distributed under theCreativeCommonsAttribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A nonmesocyclone Tornado traversed the Hong Kong International Airport on September 6, 2004 directly impacting a surface weather station. This allowed for 1-second 10-meter above ground level (AGL) wind observations through the core of the Tornado. Integration of these 10-meter AGL wind data with Ground-Based Velocity Track (GBVTD) wind retrievals derived from LIDAR data provided a time history of the three-dimensional wind field of the Tornado. These data indicate a progressive decrease in radial inflow with time and little to no radial inflow near the time the Tornado crosses the surface weather station. Anemometer observations suggest that the tangential winds approximate a modified-Rankine vortex outside the radius of maximum winds, suggesting that frictionally induced radial inflow was confined below 10mAGL. The radial-height distribution of angular momentum depicts an increase in low-level angular momentum just prior to the Tornado reaching its maximum intensity. 1
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Wind Field of a Nonmesocyclone Anticyclonic Tornado Crossing the Hong Kong International Airport
Hindawi Limited, 2014Co-Authors: Karen Kosiba, Paul Robinson, P. W. Chan, Joshua WurmanAbstract:A nonmesocyclone Tornado traversed the Hong Kong International Airport on September 6, 2004 directly impacting a surface weather station. This allowed for 1-second 10-meter above ground level (AGL) wind observations through the core of the Tornado. Integration of these 10-meter AGL wind data with Ground-Based Velocity Track (GBVTD) wind retrievals derived from LIDAR data provided a time history of the three-dimensional wind field of the Tornado. These data indicate a progressive decrease in radial inflow with time and little to no radial inflow near the time the Tornado crosses the surface weather station. Anemometer observations suggest that the tangential winds approximate a modified-Rankine vortex outside the radius of maximum winds, suggesting that frictionally induced radial inflow was confined below 10 m AGL. The radial-height distribution of angular momentum depicts an increase in low-level angular momentum just prior to the Tornado reaching its maximum intensity
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in situ doppler radar and video observations of the interior structure of a Tornado and the wind damage relationship
Bulletin of the American Meteorological Society, 2012Co-Authors: Joshua Wurman, Karen Kosiba, Paul RobinsonAbstract:Direct observations of the winds inside a Tornado were obtained with an instrumented armored vehicle, the Tornado Intercept Vehicle (TIV), and integrated with finescale mobile Doppler radar (Doppler on Wheels) data revealing, for the first time, the structure of the near-ground three-dimensional wind field in and around the core region of a strong Tornado, and permitting comparison with conceptual models. Inward and upward spiraling near-surface flow, upward motion near the surface, and an axial downdraft aloft are documented, as well as a periodic oscillation in Tornado intensity. Simultaneous video documentation of damage occurring during the Tornado is related to the direct wind observations, permitting the first comparisons of the time history of damage to the time history of directly measured winds and a limited evaluation of the underlying assumptions and quantitative relationships in the enhanced Fujita (EF) scale.
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finescale single and dual doppler analysis of Tornado intensification maintenance and dissipation in the orleans nebraska supercell
Monthly Weather Review, 2010Co-Authors: Joshua Wurman, David C. Dowell, Yvette Richardson, Paul Markowski, Karen Kosiba, Paul RobinsonAbstract:Abstract Finescale single- and dual-Doppler observations are used to diagnose the three-dimensional structure of the wind field surrounding a Tornado that occurred near the town of Orleans, Nebraska, on 22 May 2004. The evolution of the vorticity and divergence fields and other structures near the Tornado are documented in the lowest kilometer. Changes in Tornado intensity are compared to the position of the Tornado relative to primary and secondary gust fronts. Circulation on scales of a few kilometers surrounding the Tornado remains relatively constant during the analysis period, which spans the intensifying and mature periods of the Tornado’s life cycle. Stretching of vertical vorticity and tilting of horizontal vorticity are diagnosed, but the latter is near or below the threshold of detectability in this analysis during the observation period in the analyzed domain. Low-level circulation within 500 m of the Tornado increased several minutes before vortex-relative and ground-relative near-surface wind...
K A Marsh - One of the best experts on this subject based on the ideXlab platform.
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a galactic dust devil far infrared observations of the Tornado supernova remnant candidate
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: H Chawner, A D P Howard, Haley Louise Gomez, M Matsuura, F D Priestley, M J Barlow, I De Looze, Andreas Papageorgiou, K A MarshAbstract:We present complicated dust structures within multiple regions of the candidate supernova remnant (SNR) the ‘Tornado’ (G357.7−0.1) using observations with Spitzer and Herschel. We use Point Process Mapping, PPMAP, to investigate the distribution of dust in the Tornado at a resolution of 8″, compared to the native telescope beams of 5 − 36″. We find complex dust structures at multiple temperatures within both the head and the tail of the Tornado, ranging from 15 to 60 K. Cool dust in the head forms a shell, with some overlap with the radio emission, which envelopes warm dust at the X-ray peak. Akin to the terrestrial sandy whirlwinds known as ‘Dust Devils’, we find a large mass of dust contained within the Tornado. We derive a total dust mass for the Tornado head of 16.7 M⊙, assuming a dust absorption coefficient of κ300 =0.56m2kg−1, which can be explained by interstellar material swept up by a SNR expanding in a dense region. The X-ray, infra-red, and radio emission from the Tornado head indicate that this is a SNR. The origin of the tail is more unclear, although we propose that there is an X-ray binary embedded in the SNR, the outflow from which drives into the SNR shell. This interaction forms the helical tail structure in a similar manner to that of the SNR W50 and microquasar SS433.
Howard B. Bluestein - One of the best experts on this subject based on the ideXlab platform.
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rapid scan polarimetric doppler radar observations of Tornadogenesis and Tornado dissipation in a tornadic supercell the el reno oklahoma storm of 24 may 2011
Monthly Weather Review, 2015Co-Authors: Jana Lesak Houser, Howard B. Bluestein, Jeffrey C. SnyderAbstract:AbstractOn 24 May 2011, a mobile, rapid-scan, X-band, polarimetric, Doppler radar (RaXPol) collected data on a supercell as it produced two Tornadoes near El Reno, Oklahoma. The first Tornado, rated an EF-3, was documented from intensification to decay, and the genesis and intensification of a second Tornado that was rated an EF-5 was subsequently also documented.The objective of this study is to examine the spatiotemporal evolution of the rotation associated with the Tornadoes (i) as the first Tornado weakened to subtornadic intensity and (ii) as the second Tornado formed and intensified. It is found that weakening did not occur monotonically. The transition from tornadic to subtornadic intensity over the depth of the radar volume (~4 km) occurred in less than 30 s, but this behavior is contingent upon the threshold for Doppler shear used to define the Tornado. Similarly, the onset of a tornadic-strength Doppler velocity couplet occurred within a 30-s period over all elevations.Additionally, the evolutio...
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mobile x band polarimetric doppler radar observations of the 4 may 2007 greensburg kansas tornadic supercell
Monthly Weather Review, 2012Co-Authors: Robin L Tanamachi, Howard B. Bluestein, Jana B Houser, Stephen J Frasier, Kery HardwickAbstract:AbstractOn 4 May 2007, a supercell produced an EF-5 Tornado that severely damaged the town of Greensburg, Kansas. Volumetric data were collected in the “Greensburg storm” by the University of Massachusetts X-band, mobile, polarimetric Doppler radar (UMass X-Pol) for 70 min; 10 Tornadoes were detected. This mobile Doppler radar dataset is one of only a few documenting an EF-5 Tornado and the supercell’s transition from short-track, cyclic Tornado production (mode 1) to long-track Tornado production (mode 2). Using bootstrap confidence intervals, it is determined that the mode-2 Tornadoes moved in the same direction as the supercell vault. In contrast, the mode-1 Tornadoes moved to the left with respect to the vault.From polarimetric data collected in this storm, the authors infer the presence of large, oblate drops (high ZDR, high ρhv) in the forward flank and surrounding some of the Tornadoes. The authors speculate that the weak-echo column (WEC) in the Greensburg Tornado, which extended above 10 km AGL, ...
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mobile doppler radar observations of a Tornado in a supercell near bassett nebraska on 5 june 1999 part ii Tornado vortex structure
Monthly Weather Review, 2003Co-Authors: Howard B. Bluestein, Wenchau Lee, Michael M Bell, Christopher C Weiss, Andrew L PazmanyAbstract:Abstract This is Part II of a paper detailing an analysis of high-resolution wind and reflectivity data collected by a mobile, W-band Doppler radar; the analysis depicts the near-surface life history of a Tornado in a supercell in north-central Nebraska on 5 June 1999. The structure of the Tornado vortex near the ground is described from a sequence of sector scans at 10–15-s intervals during much of the lifetime of the Tornado. The formation of the Tornado vortex near the ground is described in Part I. The wind and reflectivity features in the Tornado evolved on timescales of 10 s or less. A time history of the azimuthally averaged azimuthal and radial wind profiles and the asymmetric components of the azimuthal and radial wind fields in the Tornado were estimated by applying the ground-based velocity track display (GBVTD) technique to the Doppler wind data. If the magnitude of the asymmetric part of the radial wind component were indeed much less than that of the azimuthal wind component (a necessary req...
