Pressure at the ground in a large tornado

Winn, W. P.; Hunyady, S. J.; Aulich, G. D.

doi:10.1029/1999jd900387

Cited by 40 publications

(44 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The calculated pressure deficit for a tornado with V max ϭ 80 m s Ϫ1 and b ϭ 0.6-0.7, similar to the Mulhall tornado, is 85 to 91 hPa, very similar to the GBVTD-retrieved pressure deficit (see text). It is also similar to the pressure deficit measured in similar intensity tornadoes (Winn et al 1999;Lee et al 2004). The calculated pressure deficit for a tornado with V max ϭ 52 m s Ϫ1 , is about 35-40 hPa, which is close to the observed 31-41-hPa drop observed in the Stratford, Texas (2003), tornado, which exhibited a V max ϭ 53 m s Ϫ1 (Wurman and Samaras 2004).…”

Section: ͑A4͒supporting

confidence: 72%

“…For example, the total central pressure deficit is 3 hPa higher than the cyclostrophic central pressure deficit. These pressure deficits are comparable with rare in situ observations (Winn et al 1999;Lee et al 2004;Wurman and Samaras 2004) in strong tornadoes, as discussed in the next subsection. It can be shown that the central pressure deficit of a tornado possesses a variation of a Rankine-combined wind profile that can be derived analytically (details are provided in the appendix for interested readers).…”

supporting

confidence: 73%

“…The maximum tangential wind in the Dallas tornado (2 April 1957) derived from this method was ϳ75 m s Ϫ1 at a radius of ϳ40 m and an elevation of 70 m (Hoecker 1960) while the maximum tangential wind was ϳ80 m s Ϫ1 at a radius of ϳ200 m and an altitude of 90 m in the Union City, Oklahoma, tornado (Golden and Purcell 1978). To date, only a few in situ wind and pressure measurements are available in the vicinity of tornadoes (e.g., Fujita et al 1970;Winn et al 1999;Wurman and Samaras 2004;Lee et al 2004). Recently, mobile Doppler radar measurements show that the peak wind in the most intense tornadoes exceeds 100 m s Ϫ1 (Wurman 2002, hereafter W02;Alexander and Wurman 2005, hereafter Part I;Wurman and Alexander 2005, hereafter Part II).…”

Section: Introductionmentioning

confidence: 99%

“…Figure 10 shows the comparison among perturbation pressure profiles at four times (0310:03, 0312:59, 0316:28, and 0319:30 UTC) of the Mulhall tornado derived from the GBVTD technique and the Allison tornado measured by an E-Turtle (all pressure deficits are normalized at r ϭ 3 km). Note that Winn et al (1999) E-Turtle was located as close as 660 m from the tornado center. These pressure profiles show remarkable similarity between r ϭ 800 m and 3 km except for the 0310:03 UTC.…”

mentioning

confidence: 99%

“…The first surface pressure measurement of a large tornado is the E-Turtle pressure trace of the F4 Allison, Texas, tornado in 1995 (Winn et al 1999). Although there is only limited Doppler radar data to confirm the size of the Allison tornado (Wurman and Alexander 2004), a 1.3-km-wide F3 damage swath indicated that it might have been unusually large and similar in size to the Mulhall tornado.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Diagnosed Three-Dimensional Axisymmetric Structure of the Mulhall Tornado on 3 May 1999

Lee

Wurman

2005

Journal of the Atmospheric Sciences

140

View full text Add to dashboard Cite

On 3 May 1999, an unusually large tornado that caused F4-level damage and killed several people was intercepted by the Doppler on Wheels (DOW) mobile radar near Mulhall, Oklahoma, from a range of 4 to 9 km, resulting in high-resolution volumetric data every 55 s up to 1.5-km altitude over a period of 14 min. For the first time, the evolution and three-dimensional structure of a tornado were deduced using the ground-based velocity track display (GBVTD) technique. After the circulation center was determined, the tangential wind and radial wind were derived from the GBVTD technique at each radius and height. In addition, the axisymmetric vertical velocity, angular momentum, vorticity, and perturbation pressure were deduced from the tangential and radial wind fields. This study focuses on the axisymmetric aspects of this tornado.The primary circulation of the Mulhall tornado consisted of an 84 m s Ϫ1 peak axisymmetric tangential wind with the radius of maximum wind (RMW) ranging from 500 to 1000 m. The secondary circulation exhibited a two-cell structure characterized by a central downdraft surrounded by an annular updraft near the RMW. The calculated maximum pressure deficit from a 3-km radius to the tornado center at 50-m altitude was Ϫ80 hPa. The maximum vorticity during the first 8 min of observation was located inside the RMW away from the tornado center. This vorticity profile satisfied the necessary condition of barotropic instability. As the tornado weakened afterward, the vorticity monotonically increased toward the center. The computed swirl ratios were between 2 and 6, consistent with the observed multiple vortex radar signatures and the vorticity pattern. Swirl ratios were generally smaller during the weakening phase.

show abstract

Section: ͑A4͒supporting

confidence: 72%

supporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Diagnosed Three-Dimensional Axisymmetric Structure of the Mulhall Tornado on 3 May 1999

Lee

Wurman

2005

Journal of the Atmospheric Sciences

140

View full text Add to dashboard Cite

show abstract

Analysis of the horizontal two‐dimensional near‐surface structure of a winter tornadic vortex using high‐resolution in situ wind and pressure measurements

Kato

Kusunoki²,

Satô³

et al. 2015

JGR Atmospheres

View full text Add to dashboard Cite

The horizontal two-dimensional near-surface structure of a tornadic vortex within a winter storm was analyzed. The tornadic vortex was observed on 10 December 2012 by the high-resolution in situ observational linear array of wind and pressure sensors (LAWPS) system in conjunction with a high-resolution Doppler radar. The 0.1 s maximum wind speed and pressure deficit near the ground were recorded as 35.3 m s À1 and À3.8 hPa, respectively. The horizontal two-dimensional distributions of the tornadic vortex wind and pressure were retrieved by the LAWPS data, which provided unprecedented observational detail on the following important features of the near-surface structure of the tornadic vortex. Asymmetric convergent inflow toward the vortex center existed. Total wind speed was strong to the right and rear side of the translational direction of the vortex and weak in the forward part of the vortex possibly because of the strong convergent inflow in that region. The tangential wind speed profile of the vortex was better approximated using a modified Rankine vortex rather than the Rankine vortex both at 5 m above ground level (agl) and 100 m agl, and other vortex models (Burgers-Rott vortex and Wood-White vortex) were also compared. The cyclostrophic wind balance was violated in the core radius R 0 and outside the core radius in the forward sector; however, it was held with a relatively high accuracy of approximately 14% outside the core of the vortex in the rearward sector (from 2 R 0 to 5 R 0 ) near the ground.

show abstract

Simulating tornado-like flows: the effect of the simulator’s geometry

2019

View full text Add to dashboard Cite

Within the wind engineering community, a series of physical simulators of differing geometries have been used to investigate the flow-field of tornado-like vortices. This paper examines the influence that the geometry of a simulator can have on the generated flow field. Surface pressure and velocity data have been measured for two swirl ratios (S = 0.30 and S = 0.69) in two different simulators of different scale and varying geometry. The results of this research suggest that far from being a mature research field, there are still many unresolved questions that need to be addressed before data obtained from such simulators can be used with confidence in practice.

show abstract

Pressure at the ground in a large tornado

Cited by 40 publications

References 17 publications

Diagnosed Three-Dimensional Axisymmetric Structure of the Mulhall Tornado on 3 May 1999

Diagnosed Three-Dimensional Axisymmetric Structure of the Mulhall Tornado on 3 May 1999

Analysis of the horizontal two‐dimensional near‐surface structure of a winter tornadic vortex using high‐resolution in situ wind and pressure measurements

Simulating tornado-like flows: the effect of the simulator’s geometry

Contact Info

Product

Resources

About