Improvement of Tornado Warnings by Doppler Radar Measurement of Mesocyclone Rotational Kinetic Energy

Donaldson, Ralph J.; Desrochers, Paul R.

doi:10.1175/1520-0434(1990)005<0247:iotwbd>2.0.co;2

Cited by 8 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been pointed out (e.g., Trapp 1999) that intense low-level mesocyclones are not a sufficient condition for tornadogenesis. However, a correlation between the rotational velocity and shear of mesocyclones observed by Doppler radar and tornadogenesis has been observed (e.g., Donaldson andDesrochers 1990, Burgess andLemon 1990); this implies that mesocyclone intensification upon interaction with a gravity wave may lead to tornadogenesis in some situations. Such interactions have been speculated upon by previous authors (e.g., Miller and Sanders 1980), and even observed by Kilduff (1999) and Barker (2006).…”

Section: Discussionmentioning

confidence: 99%

The Interactions of Gravity Waves with Mesocyclones: Preliminary Observations and Theory

Coleman

Knupp

2008

Monthly Weather Review

View full text Add to dashboard Cite

Apparent interactions between ducted gravity waves and preexisting mesocyclones are investigated. Preliminary analyses of Weather Surveillance Radar-1988 Doppler (WSR-88D) observations from several cases reveal that the intersection of fine lines, whose propagation speed is consistent with that of gravity waves, and existing mesocyclones leads to an increase in the rotational velocity of the mesocyclone. Utilizing simplified ducted wave kinematics and the vorticity equation, changes in vorticity associated with convergence-divergence and perturbation wind shear within the gravity wave are examined. Convergence ahead of wave ridges may be significant, causing mesocyclone intensification through vorticity stretching. It will also be shown that a wave may significantly change the vertical wind shear and streamwise vorticity in storm inflow. A simple one-dimensional model is presented, which shows that vorticity decreases temporarily ahead of the wave ridge, then increases rapidly behind the ridge as positive tilting and stretching act together. The mesocyclone vorticity reaches a peak just ahead of the wave ridge, then begins to rapidly decrease behind the ridge. Model results compared very well to actual measurements in a sample case in which a mesocyclone interacted with two gravity waves of different amplitudes.

show abstract

Section: Discussionmentioning

confidence: 99%

The Interactions of Gravity Waves with Mesocyclones: Preliminary Observations and Theory

Coleman

Knupp

2008

Monthly Weather Review

View full text Add to dashboard Cite

show abstract

“…There are algorithmic radar techniques for the identification of all of these severe weather features (Dance and Potts, 2002;Donaldson and Desrochers, 1990;Johnson et al, 1998;Joe et al, 2004;Kessler and Wilson, 1971;Lakshmanan et al, 2003;Lakshmanan and Smith, 2009;Lenning et al, 1998;Mitchell et al, 1998;Stumpf et al, 1998;Winston, 1998;Witt et al, 1998a, Witt et al, 1998b. The efficacy of the detection depends on the radar scan strategy and quality of the radar (range, azimuth resolution, cycle time, sensitivity, elevation angles, number of elevation tilts, etc Heinselman et al, 2008;Lakshmanan et al, 2006;Marshall and Ballantyne, 1975;McLaughlin et al, 2009;Vasiloff, 2001).…”

Section: Thunderstormmentioning

confidence: 99%

Automated Processing of Doppler Radar Data for Severe Weather Warnings

Joe¹,

Dance²,

Lakshmanan³

et al. 2012

Doppler Radar Observations - Weather Radar, Wind Profiler, Ionospheric Radar, and Other Advanced Applications

View full text Add to dashboard Cite

“…Another tornado predictor is the excess rotational kinetic energy (ERKE; Donaldson and Desrochers 1990). At a single height, the rotational kinetic energy (RKE) is proportional to ⌫ 2 D , and so is similar to, but more variable than, ⌫ D .…”

Section: Circulation Shear and Erke Of Doppler Signaturementioning

confidence: 99%

“…Time variation of ERKE for the BRV of EXP I forEBWs of 1.02°and 1.39°and ranges of 25 and 50 km. ERKE is in climatological mature mesocyclone (CMM) units (i.e., it is normalized by the ERKE value for the climatological mature mesocyclone; seeDonaldson and Desrochers 1990). The tornado forms at 6 min.…”

mentioning

confidence: 99%

Simulated Doppler Velocity Signatures of Evolving Tornado-Like Vortices

Davies‐Jones

Wood

2006

Journal of Atmospheric and Oceanic Technology

View full text Add to dashboard Cite

Doppler radar observations have revealed a class of atmospheric vorti-ces (tropical cyclones, tornadoes, dust devils) that possess elliptical radar reflectivity signatures. One famous example is Typhoon Herb (1996) that maintained its elliptical reflectivity structure over a 40-hour period. Theoretical work and dual-Doppler analyses of observed tropical cyclones have suggested two physical mechanisms that can explain the formation of two types of elliptical vortices observed in nature, namely, the combination of a circular vortex with either a wavenumber two vortex Rossby wave or a deformation field. The characteristics of these two types of elliptical vorti-ces and their corresponding Doppler velocity signatures have not been previously examined. Idealized elliptical vortices consisting of a Rankine vortex combined with wavenumber two disturbances are constructed and sampled by a hypothetical Doppler radar. The Doppler velocity patterns of all wavenumber two cases shown in this study are visually similar. The characteristics of the two-dimensional flow patterns and the corresponding Doppler velocities produced by an idealized vortex Rossby wave and deformation field are illustrated. The ground-based velocity track display (GBVTD) single Dop-pler vortex wind retrieval technique was performed on these two types of elliptical vortices. The GBVTD technique can retrieve wavenumber two components in the vortex Rossby wave case outside the RMW but failed to retrieve wavenumber two structure of the deformation case for all radii. It TAO, Vol. 17, No. 2, June 2006 430 can be seen that when the phase of the wavenumber two V T is ahead of V R by π/4 with same amplitude, GBVTD coefficients A3 and B3 are near zero; hence, GBVTD technique cannot retrieve the wavenumber two amplitude in these conditions. However, by knowing the elliptical shape of the vortex as a priori these two mechanisms can still be distinguished by the characteristics of the corresponding GBVTD coefficients.

show abstract

Improvement of Tornado Warnings by Doppler Radar Measurement of Mesocyclone Rotational Kinetic Energy

Cited by 8 publications

References 0 publications

The Interactions of Gravity Waves with Mesocyclones: Preliminary Observations and Theory

The Interactions of Gravity Waves with Mesocyclones: Preliminary Observations and Theory

Automated Processing of Doppler Radar Data for Severe Weather Warnings

Simulated Doppler Velocity Signatures of Evolving Tornado-Like Vortices

Contact Info

Product

Resources

About