Editorial Type:
Article
Article Type:
Research Article

A Phase-Plot Method for Diagnosing Vorticity Concentration Mechanisms in Mesoscale Convective Vortices

James R. Kirk Department of Physics and Technology, Edinboro University of Pennsylvania, Edinboro, Pennsylvania

Search for other papers by James R. Kirk in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Mar 2007
DOI:
https://doi.org/10.1175/MWR3322.1
Page(s):
801–820
Restricted access

Abstract

Mesoscale convective vortex (MCV) analysis results show that these vortices form by way of different evolutionary paths. Rewriting the traditional form of the relative vertical vorticity equation in terms of momentum advection curl produces an alternative form of the equation containing two terms. When the terms are normalized and plotted on orthogonal axes, a phase-plot path depicting MCV evolutionary growth is created. Thermodynamics is included in the phase plot by correlating the path to the heating characteristics of the troposphere. The application of the phase-plot scheme to several cases shows that for MCV formation events, there are two interconnected regions that combine to produce the vortex. The upper-middle- and upper-troposphere vorticity growth is governed primarily by vertical motion, with heating driving the vorticity growth in the upper-middle region. The lower-middle and lower-troposphere vorticity growth is governed primarily by horizontal motion, with the vertical heating gradient driving the vorticity growth in the lower-middle region. Which regime leads the vorticity growth is found to be case dependent. In the middle troposphere, evolutionary paths are governed by the relative strengths of heating and heating gradient. Additional phase-plot and mesoscale analyses clarify the characteristics of two MCV formation modes. In some cases, heating drives the complete formation of the MCV, whereas in cases with lesser heating, tipping is vital to the MCV formation process. In total, these results help synthesize many of the various discoveries regarding the origin and formation of the MCV.

Corresponding author address: Dr. James R. Kirk, Department of Physics and Technology, Edinboro University of Pennsylvania, G-34 Hendricks Hall, Edinboro, PA 16444. Email: kirkj@edinboro.edu

Abstract

Mesoscale convective vortex (MCV) analysis results show that these vortices form by way of different evolutionary paths. Rewriting the traditional form of the relative vertical vorticity equation in terms of momentum advection curl produces an alternative form of the equation containing two terms. When the terms are normalized and plotted on orthogonal axes, a phase-plot path depicting MCV evolutionary growth is created. Thermodynamics is included in the phase plot by correlating the path to the heating characteristics of the troposphere. The application of the phase-plot scheme to several cases shows that for MCV formation events, there are two interconnected regions that combine to produce the vortex. The upper-middle- and upper-troposphere vorticity growth is governed primarily by vertical motion, with heating driving the vorticity growth in the upper-middle region. The lower-middle and lower-troposphere vorticity growth is governed primarily by horizontal motion, with the vertical heating gradient driving the vorticity growth in the lower-middle region. Which regime leads the vorticity growth is found to be case dependent. In the middle troposphere, evolutionary paths are governed by the relative strengths of heating and heating gradient. Additional phase-plot and mesoscale analyses clarify the characteristics of two MCV formation modes. In some cases, heating drives the complete formation of the MCV, whereas in cases with lesser heating, tipping is vital to the MCV formation process. In total, these results help synthesize many of the various discoveries regarding the origin and formation of the MCV.

Corresponding author address: Dr. James R. Kirk, Department of Physics and Technology, Edinboro University of Pennsylvania, G-34 Hendricks Hall, Edinboro, PA 16444. Email: kirkj@edinboro.edu

Save
Cover Monthly Weather Review
Monthly Weather Review

  • Adlerman, E. J. , K. K. Droegemeier , and R. Davies-Jones , 1999: A numerical simulation of cyclic mesocyclogenesis. J. Atmos. Sci., 56 , 2045–2069.

    • Search Google Scholar
    • Export Citation

  • Augustine, J. A. , and K. W. Howard , 1988: Mesoscale convective complexes over the United States during 1985. Mon. Wea. Rev., 116 , 685–701.

    • Search Google Scholar
    • Export Citation

  • Augustine, J. A. , and K. W. Howard , 1991: Mesoscale convective complexes over the United States during 1986 and 1987. Mon. Wea. Rev., 119 , 1575–1589.

    • Search Google Scholar
    • Export Citation

  • Bartels, D. L. , and R. A. Maddox , 1991: Midlevel cyclonic vortices generated by mesoscale convective systems. Mon. Wea. Rev., 119 , 104–118.

    • Search Google Scholar
    • Export Citation

  • Bohren, C. F. , and B. Albrecht , 1998: Atmospheric Thermodynamics. Oxford University Press, 402 pp.

  • Bosart, L. F. , and F. Sanders , 1981: The Johnstown Flood of July 1977: A long-lived convective system. J. Atmos. Sci., 38 , 1616–1642.

    • Search Google Scholar
    • Export Citation

  • Brandes, E. A. , 1990: Evolution and structure of the 6–7 May 1985 mesoscale convective system and associated vortex. Mon. Wea. Rev., 118 , 109–127.

    • Search Google Scholar
    • Export Citation

  • Brandes, E. A. , and C. L. Ziegler , 1993: Mesoscale downdraft influences on vertical vorticity in a mature mesoscale convective system. Mon. Wea. Rev., 121 , 1337–1353.

    • Search Google Scholar
    • Export Citation

  • Chen, S. S. , and W. M. Frank , 1993: A numerical study of the genesis of extratropical convective mesovortices. Part I: Evolution and dynamics. J. Atmos. Sci., 50 , 2401–2426.

    • Search Google Scholar
    • Export Citation

  • Cotton, W. R. , M-S. Lin , R. L. McAnelly , and C. J. Tremback , 1989: A composite model of mesoscale convective complexes. Mon. Wea. Rev., 117 , 765–783.

    • Search Google Scholar
    • Export Citation

  • Cram, T. A. , M. T. Montgomery , and R. F. A. Hertenstein , 2002: Early evolution of vertical vorticity in a numerically simulated idealized convective line. J. Atmos. Sci., 59 , 2113–2127.

    • Search Google Scholar
    • Export Citation

  • Davis, C. A. , and M. L. Weisman , 1994: Balanced dynamics of mesoscale vortices produced in simulated convective systems. J. Atmos. Sci., 51 , 2005–2030.

    • Search Google Scholar
    • Export Citation

  • Davis, C. A. , and S. B. Trier , 2002: Cloud-resolving simulations of mesoscale vortex intensification and its effect on a serial mesoscale convective system. Mon. Wea. Rev., 130 , 2839–2858.

    • Search Google Scholar
    • Export Citation

  • Davis, C. A. , D. A. Ahijevych , and S. B. Trier , 2002: Detection and prediction of warm season midtropospheric vortices by the rapid update cycle. Mon. Wea. Rev., 130 , 24–42.

    • Search Google Scholar
    • Export Citation

  • Fritsch, J. M. , 1986: Modification of mesoscale convective weather systems. Precipitation Enhancement—A Scientific Challenge, Meteor. Monogr., No. 43, Amer. Meteor. Soc., 77–86.

  • Fritsch, J. M. , and R. A. Maddox , 1981: Convectively driven mesoscale weather systems aloft. Part I: Observations. J. Appl. Meteor., 20 , 9–19.

    • Search Google Scholar
    • Export Citation

  • Fritsch, J. M. , and G. S. Forbes , 2001: Mesoscale convective systems. Severe Convective Storms, Meteor. Monogr., No. 50, Amer. Meteor. Soc., 323–358.

  • Fritsch, J. M. , J. D. Murphy , and J. S. Kain , 1994: Warm core vortex amplification over land. J. Atmos. Sci., 51 , 1780–1807.

  • Haynes, P. H. , and M. E. McIntyre , 1987: On the evolution of vorticity and potential vorticity in the presence of diabatic heating and frictional or other forces. J. Atmos. Sci., 44 , 828–841.

    • Search Google Scholar
    • Export Citation

  • Hertenstein, R. F. A. , and W. H. Schubert , 1991: Potential vorticity anomalies associated with squall lines. Mon. Wea. Rev., 119 , 1663–1672.

    • Search Google Scholar
    • Export Citation

  • Holton, J. R. , 1992: An Introduction to Dynamic Meteorology. 3d ed. Academic Press, 511 pp.

  • Jiang, H. , and D. J. Raymond , 1995: Simulation of a mature mesoscale convective system using a nonlinear balance model. J. Atmos. Sci., 52 , 161–175.

    • Search Google Scholar
    • Export Citation

  • Johnson, R. H. , and B. E. Mapes , 2001: Mesoscale processes and severe convective weather. Severe Convective Storms, Meteor. Monogr., No. 50, Amer. Meteor. Soc., 71–122.

  • Johnston, E. C. , 1981: Mesoscale vorticity centers induced by mesoscale convective complexes. M.S. thesis, Dept. of Atmospheric and Oceanic Sciences, University of Wisconsin, 54 pp.

  • Kirk, J. R. , 2003: Comparing the dynamical development of two mesoscale convective vortices. Mon. Wea. Rev., 131 , 862–890.

  • Knievel, J. C. , and R. H. Johnson , 2002: The kinematics of a midlatitude, continental mesoscale convective system and its mesoscale vortex. Mon. Wea. Rev., 130 , 1749–1770.

    • Search Google Scholar
    • Export Citation

  • Knievel, J. C. , and R. H. Johnson , 2003: A scale-discriminating vorticity budget for a mesoscale vortex in a midlatitude, continental mesoscale convective system. J. Atmos. Sci., 60 , 781–794.

    • Search Google Scholar
    • Export Citation

  • Knievel, J. C. , D. S. Nolan , and J. P. Kossin , 2004: Imbalance in a mesoscale vortex within a midlatitude, continental mesoscale convective system. J. Atmos. Sci., 61 , 1827–1832.

    • Search Google Scholar
    • Export Citation

  • Laing, A. G. , and J. M. Fritsch , 1993a: Mesoscale convective complexes in Africa. Mon. Wea. Rev., 121 , 2254–2263.

  • Laing, A. G. , and J. M. Fritsch , 1993b: Mesoscale convective complexes over the Indian monsoon region. J. Climate, 6 , 911–919.

  • Laing, A. G. , and J. M. Fritsch , 1997: The global population of mesoscale convective complexes. Quart. J. Roy. Meteor. Soc., 123 , 389–405.

    • Search Google Scholar
    • Export Citation

  • Leary, C. A. , and E. N. Rappaport , 1987: The life cycle and internal structure of a mesoscale convective complex. Mon. Wea. Rev., 115 , 1503–1527.

    • Search Google Scholar
    • Export Citation

  • Maddox, R. A. , 1980: Mesoscale convective complexes. Bull. Amer. Meteor. Soc., 61 , 1374–1387.

  • Maddox, R. A. , 1983: Large-scale meteorological conditions associated with mid-latitude, mesoscale convective complexes. Mon. Wea. Rev., 111 , 1475–1493.

    • Search Google Scholar
    • Export Citation

  • Menard, R. D. , and J. M. Fritsch , 1989: A mesoscale convective complex–generated inertially stable warm core vortex. Mon. Wea. Rev., 117 , 1237–1261.

    • Search Google Scholar
    • Export Citation

  • Miller, D. , and J. M. Fritsch , 1991: Mesoscale convective complexes in the western Pacific region. Mon. Wea. Rev., 119 , 2978–2992.

    • Search Google Scholar
    • Export Citation

  • Olsson, P. Q. , and W. R. Cotton , 1997a: Balanced and unbalanced circulations in a primitive equation simulation of a midlatitude MCC. Part I: Numerical simulation. J. Atmos. Sci., 54 , 457–478.

    • Search Google Scholar
    • Export Citation

  • Olsson, P. Q. , and W. R. Cotton , 1997b: Balanced and unbalanced circulations in a primitive equation simulation of a midlatitude MCC. Part II: Analysis of balance. J. Atmos. Sci., 54 , 479–497.

    • Search Google Scholar
    • Export Citation

  • Parker, M. D. , and R. H. Johnson , 2000: Organizational modes of midlatitude mesoscale convective systems. Mon. Wea. Rev., 128 , 3413–3436.

    • Search Google Scholar
    • Export Citation

  • Raymond, D. J. , 1992: Nonlinear balance and potential-vorticity thinking at large Rossby number. Quart. J. Roy. Meteor. Soc., 118 , 987–1015.

    • Search Google Scholar
    • Export Citation

  • Raymond, D. J. , and H. Jiang , 1990: A theory for long-lived mesoscale convective systems. J. Atmos. Sci., 47 , 3067–3077.

  • Rogers, R. F. , and J. M. Fritsch , 2001: Surface cyclogenesis from convectively driven amplification of midlevel mesoscale convective vortices. Mon. Wea. Rev., 129 , 605–637.

    • Search Google Scholar
    • Export Citation

  • Scott, J. D. , and S. A. Rutledge , 1995: Doppler radar observations of an asymmetric mesoscale convective system and associated vortex couplet. Mon. Wea. Rev., 123 , 3437–3457.

    • Search Google Scholar
    • Export Citation

  • Skamarock, W. C. , M. L. Weisman , and J. B. Klemp , 1994: Three-dimensional evolution of simulated long-lived squall lines. J. Atmos. Sci., 51 , 2563–2584.

    • Search Google Scholar
    • Export Citation

  • Trier, S. B. , and C. A. Davis , 2002: Influence of balanced motions on heavy precipitation within a long-lived convectively generated vortex. Mon. Wea. Rev., 130 , 877–899.

    • Search Google Scholar
    • Export Citation

  • Velasco, I. , and J. M. Fritsch , 1987: Mesoscale convective complexes in the Americas. J. Geophys. Res., 92 , 9591–9613.

  • Verlinde, J. , and W. R. Cotton , 1990: A mesovortex couplet in the trailing anvil region of a multicellular convective complex. Mon. Wea. Rev., 118 , 993–1010.

    • Search Google Scholar
    • Export Citation

  • Weisman, M. L. , and C. A. Davis , 1998: Mechanisms for the generation of mesoscale vortices within quasi-linear convective systems. J. Atmos. Sci., 55 , 2603–2622.

    • Search Google Scholar
    • Export Citation

  • Wetzel, P. J. , W. R. Cotton , and R. L. McAnelly , 1983: A long-lived mesoscale convective complex. Part II: Evolution and structure of the mature complex. Mon. Wea. Rev., 111 , 1919–1937.

    • Search Google Scholar
    • Export Citation

  • Wicker, L. J. , 1996: The role of near-surface wind shear on low-level mesocyclone generation and tornadoes. Preprints, 18th Conf. on Severe Local Storms, San Francisco, CA, Amer. Meteor. Soc., 115–119.

  • Zhang, D-L. , 1992: The formation of a cooling-induced mesovortex in the trailing stratiform region of a midlatitude squall line. Mon. Wea. Rev., 120 , 2763–2785.

    • Search Google Scholar
    • Export Citation

  • Zhang, D-L. , and J. M. Fritsch , 1987: Numerical simulation of the meso-β scale structure and evolution of the 1977 Johnstown flood. Part II: Inertially stable warm-core vortex and the mesoscale convective complex. J. Atmos. Sci., 44 , 2593–2612.

    • Search Google Scholar
    • Export Citation

  • Zhang, D-L. , and J. M. Fritsch , 1988: A numerical investigation of a convectively generated, inertially stable, extratropical warm-core mesovortex over land. Part I: Structure and evolution. Mon. Wea. Rev., 116 , 2660–2687.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 159 60 4
PDF Downloads 77 32 0