Advances in Atmospheric Sciences

, Volume 22, Issue 6, pp 807–820 | Cite as

Sensitivity of cyclone tracks to the initial moisture distribution: A moist potential vorticity perspective

  • Zuohao Cao
  • Da-Lin Zhang


In this study, the characteristics of moist potential vorticity (MPV) in the vicinity of a surface cyclone center and their physical processes are investigated. A prognostic equation of surface absolute vorticity is then used to examine the relationship between the cyclone tracks and negative MPV (NMPV) using numerical simulations of the life cycle of an extratropical cyclone. It is shown that the MPV approach developed herein, i.e., by tracing the peak NMPV, can be used to help trace surface cyclones during their development and mature stages. Sensitivity experiments are conducted to investigate the impact of different initial moisture fields on the effectiveness of the MPV approach. It is found that the lifetime of NMPV depends mainly on the initial moisture field, the magnitude of condensational heating, and the advection of NMPV. When NMPV moves into a saturated environment at or near a cyclone center, it can trace better the evolution of the surface cyclone due to the conservative property of MPV. It is also shown that the NMPV generation is closely associated with the coupling of large potential temperature and moisture gradients as a result of frontogenesis processes. Analyses indicate that condensation, confluence and tilting play important but different roles in determining the NMPV generation. NMPV is generated mainly through the changes in the strength of baroclinicity and in the direction of the moisture gradient due to moist and/or dry air mass intrusion into the baroclinic zone.

Key words

cyclone tracks moist potential vorticity mid-latitude cyclones 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Anthes, R. A., E.-Y. Hsie, and Y.-H. Kuo, 1987: Description of the Penn State/NCAR Mesoscale Model Version 4 (MM4). NCAR Tech. Note, NCAR / TN-282, 66pp.Google Scholar
  2. Betts, A. K., and F. J. Dugan, 1973: Empirical formula for saturation pseudoadiabats and saturation equivalent potential temperature.J. Appl. Meteor.,12, 731–732.CrossRefGoogle Scholar
  3. Browning, K. A., 1990: Organization of clouds and precipitation in extratropical cyclones.Extratropical Cyclones. The Erik Palmen Memorial Volume, C. W. Newton and E. Holopainen, Eds., Amer. Meteor. Soc., 132.Google Scholar
  4. Cao, Z., and H.-R. Cho, 1995: Generation of moist potential vorticity in extratropical cyclones.J. Atmos. Sci.,52, 3263–3281.CrossRefGoogle Scholar
  5. Cao, Z., and G. W. K. Moore, 1998: A diagnostic study of moist potential vorticity generation in an extratropical cyclone.Adv. Atmos. Sci.,15, 152–166.CrossRefGoogle Scholar
  6. Cao, Z., R. E. Stewart, and W. D. Hogg, 2001: Extreme winter warming events over the Mackenzie basin: Dynamic and thermodynamic contributions.J. Meteor. Soc. Japan,79, 785–804.CrossRefGoogle Scholar
  7. Cao, Z., M. Wang, B. A. Proctor, G. S. Strong, R. E. Stewart, H. Ritchie, and J. E. Burford, 2002: On the physical processes associated with the water budget and discharge of the Mackenzie Basin during the 1994/1995 water year.Atmos.-Ocean,40, 125–143.CrossRefGoogle Scholar
  8. Cao, Z., and D. -L. Zhang, 2004: Tracking surface cyclones with moist potential vorticity.Adv. Atmos. Sci.,21, 830–835.CrossRefGoogle Scholar
  9. Cao, Z., P. Pellerin, and H. Ritchie, 2004: Verification of mesoscale modeling for the severe rainfall event over southern Ontario in May 2000.Geophys. Res. Lett.,31, L23108, doi:10.1029/2004GL020547.CrossRefGoogle Scholar
  10. Colle, B. A., and C. F. Mass, 1999: An observational and numerical study of a cold front interacting with the Olympic Mountains during COAST IOP5.Mon. Wea. Rev.,127, 1310–1334.CrossRefGoogle Scholar
  11. Davis, C. A., and K. A. Emanuel, 1991: Potential vorticity diagnosis of cyclogenesis.Mon. Wea. Rev.,119, 1929–1953.CrossRefGoogle Scholar
  12. Fraedrich, K., R. Bach, and G. Naujokat, 1986: Single station climatology of central European fronts: Number, time and precipitation statistics.Contrib. Atmos. Phys.,59, 54–65.Google Scholar
  13. Gao, S., X. Li, and W.-K. Tao, 2004: A convective vorticity vector associated with tropical convection: A two-dimensional cloud-resolving modeling study.J. Geophys. Res.,109, D14106, doi:10.1029/2004JD004807.CrossRefGoogle Scholar
  14. Gyakum, J., 1983: On the evolution of the QE II storm. II: Dynamic and thermodynamic structure.Mon. Wea. Rev.,111, 1156–1173.CrossRefGoogle Scholar
  15. Gyakum, J., D.-L. Zhang, J. Witte, K. Thomas, and W. Wintels, 1996: CASP II and Canadian cyclones during the 1989–92 cold seasons.Atmos.-Ocean,34, 1–16.Google Scholar
  16. Hoskins, B. J., M. E. McIntyre, and A. W. Robertson, 1985: On the use and significance of isentropic potential vorticity maps.Quart. J. Roy. Meteor. Soc.,111, 877–946.CrossRefGoogle Scholar
  17. Hsie, E.-Y., R. A. Anthes, and D. Keyser, 1984: Numerical simulation of frontogenesis in a moist atmosphere.J. Atmos. Sci.,41, 2581–2594.CrossRefGoogle Scholar
  18. Hu, Q., and E. R. Reiter, 1987: A diagnostic study of explosive cyclogenesis in the lee of the Rocky Mountains.Meteor. Atmos. Phys.,36, 161–184.CrossRefGoogle Scholar
  19. Huo, Z., D.-L. Zhang, and J. Gyakum, 1998: An application of potential vorticity inversion to improving the numerical prediction of the March 1993 superstorm.Mon. Wea. Rev.,126, 424–436.CrossRefGoogle Scholar
  20. Neiman, P. J., and M. A. Shapiro, 1993: The life cycle of an extratropical marine cyclone. Part I: Frontalcyclone evolution and thermodynamic air-sea interaction.Mon. Wea. Rev.,121, 2153–2176.CrossRefGoogle Scholar
  21. Neiman, P. J., M. A. Shapiro, and L. S. Fedor, 1993: The life cycle of an extratropical marine cyclone. Part II: Mesoscale structure and diagnostics.Mon. Wea. Rev.,121, 2177–2199.CrossRefGoogle Scholar
  22. Petterssen, S., 1936: Contribution to the theory of frontogenesis.Geofys. Publ.,11, 1–27.Google Scholar
  23. Reed, R. J., G. A. Grell, and Y.-H. Kuo, 1993: The ERICA IOP 5 storm. Part II: Sensitivity tests and further diagnosis based on model output.Mon. Wea. Rev.,121, 1595–1612.CrossRefGoogle Scholar
  24. Roebber, P. J., 1984: Statistical analysis and updated climatology of explosive cyclones.Mon. Wea. Rev.,112, 1577–1589.CrossRefGoogle Scholar
  25. Shapiro, M. A., and D. Keyser, 1990: Fronts, jet streams, and the tropopause.Extratropical cyclones. The Erik Palmn Memorial Volume, C. W. Newton and E. Holopainen, Eds., Amer. Meteor. Soc., 161–191.Google Scholar
  26. Szeto, K. K., A. Tremblay, H. Guan, D. R. Hudak, R. E. Stewart, and Z. Cao, 1999: The mesoscale dynamics of freezing rain storms over eastern Canada.J. Atmos. Sci.,56, 1261–1281.CrossRefGoogle Scholar
  27. Thorpe, A. J., and S. A. Clough, 1991: Mesoscale dynamics of cold fronts: Structures described by dropsoundings in FRONTS 87.Quart. J. Roy. Meteor. Soc.,117, 903–941.CrossRefGoogle Scholar
  28. Uccellini, L. W., 1990: Processes contributing to the rapid development of extratropical cyclones.Extratropical cyclones. The Erik Palmn Memorial Volume, C. W. Newton and E. Holopainen, Eds., Amer. Meteor. Soc., 81–105.Google Scholar
  29. Weldon, R. B., 1979: Satellite training course notes. Part IV. Cloud patterns and upper air wind field. United States Air Force, AWS/TR-79/003.Google Scholar
  30. Zhang, G. J., 2003: Lagrangian study of cloud properties and their relationships to meteorological parameters over the U. S. Southern Great Plains.J. Climate,16, 2700–2716.CrossRefGoogle Scholar

Copyright information

© Advances in Atmospheric Sciences 2003

Authors and Affiliations

  • Zuohao Cao
    • 1
  • Da-Lin Zhang
    • 2
  1. 1.Meteorological Service of CanadaOntarioCanada
  2. 2.Department of MeteorologyUniversity of MarylandCollege ParkUSA

Personalised recommendations