Editorial Type:
Article
Article Type:
Research Article

A First Look at the Structure of the Wave Pouch during the 2009 PREDICT–GRIP Dry Runs over the Atlantic

Zhuo Wang University of Illinois at Urbana–Champaign, Urbana, Illinois

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Michael T. Montgomery Naval Postgraduate School, Monterey, California, and NOAA/Hurricane Research Division, Miami, Florida

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Cody Fritz University of Illinois at Urbana–Champaign, Urbana, Illinois

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Print Publication:
01 Apr 2012
DOI:
https://doi.org/10.1175/MWR-D-10-05063.1
Page(s):
1144–1163
Restricted access

Abstract

In support of the National Science Foundation Pre-Depression Investigation of Cloud-systems in the tropics (NSF PREDICT) and National Aeronautics and Space Administration Genesis and Rapid Intensification Processes (NASA GRIP) dry run exercises and National Oceanic and Atmospheric Administration Hurricane Intensity Forecast Experiment (NOAA IFEX) during the 2009 hurricane season, a real-time wave-tracking algorithm and corresponding diagnostic analyses based on a recently proposed tropical cyclogenesis model were applied to tropical easterly waves over the Atlantic. The model emphasizes the importance of a Lagrangian recirculation region within a tropical-wave critical layer (the so-called pouch), where persistent deep convection and vorticity aggregation as well as column moistening are favored for tropical cyclogenesis. Distinct scenarios of hybrid wave–vortex evolution are highlighted. It was found that easterly waves without a pouch or with a shallow pouch did not develop. Although not all waves with a deep pouch developed into a tropical storm, a deep wave pouch had formed prior to genesis for all 16 named storms originating from monochromatic easterly waves during the 2008 and 2009 seasons. On the other hand, the diagnosis of two nondeveloping waves with a deep pouch suggests that strong vertical shear or dry air intrusion at the middle–upper levels (where a wave pouch was absent) can disrupt deep convection and suppress storm development.

To sum up, this study suggests that a deep wave pouch extending from the midtroposphere (~600–700 hPa) down to the boundary layer is a necessary condition for tropical cyclone formation within an easterly wave. It is hypothesized also that a deep wave pouch together with other large-scale favorable conditions provides a sufficient condition for sustained convection and tropical cyclone formation. This hypothesized sufficient condition requires further testing and will be pursued in future work.

Corresponding author address: Zhuo Wang, Department of Atmospheric Sciences, University of Illinois at Urbana–Champaign, Urbana, IL 61801. E-mail: zhuowang@illinois.edu

Abstract

In support of the National Science Foundation Pre-Depression Investigation of Cloud-systems in the tropics (NSF PREDICT) and National Aeronautics and Space Administration Genesis and Rapid Intensification Processes (NASA GRIP) dry run exercises and National Oceanic and Atmospheric Administration Hurricane Intensity Forecast Experiment (NOAA IFEX) during the 2009 hurricane season, a real-time wave-tracking algorithm and corresponding diagnostic analyses based on a recently proposed tropical cyclogenesis model were applied to tropical easterly waves over the Atlantic. The model emphasizes the importance of a Lagrangian recirculation region within a tropical-wave critical layer (the so-called pouch), where persistent deep convection and vorticity aggregation as well as column moistening are favored for tropical cyclogenesis. Distinct scenarios of hybrid wave–vortex evolution are highlighted. It was found that easterly waves without a pouch or with a shallow pouch did not develop. Although not all waves with a deep pouch developed into a tropical storm, a deep wave pouch had formed prior to genesis for all 16 named storms originating from monochromatic easterly waves during the 2008 and 2009 seasons. On the other hand, the diagnosis of two nondeveloping waves with a deep pouch suggests that strong vertical shear or dry air intrusion at the middle–upper levels (where a wave pouch was absent) can disrupt deep convection and suppress storm development.

To sum up, this study suggests that a deep wave pouch extending from the midtroposphere (~600–700 hPa) down to the boundary layer is a necessary condition for tropical cyclone formation within an easterly wave. It is hypothesized also that a deep wave pouch together with other large-scale favorable conditions provides a sufficient condition for sustained convection and tropical cyclone formation. This hypothesized sufficient condition requires further testing and will be pursued in future work.

Corresponding author address: Zhuo Wang, Department of Atmospheric Sciences, University of Illinois at Urbana–Champaign, Urbana, IL 61801. E-mail: zhuowang@illinois.edu
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  • Bracken, W. E., and L. F. Bosart, 2000: The role of synoptic-scale flow during tropical cyclogenesis over the North Atlantic Ocean. Mon. Wea. Rev., 128, 353–376.

    • Search Google Scholar
    • Export Citation

  • Braun, S. A., 2010: Reevaluating the role of the Saharan air layer in Atlantic tropical cyclogenesis and evolution. Mon. Wea. Rev., 138, 2007–2037.

    • Search Google Scholar
    • Export Citation

  • Carlson, T. N., 1969: Synoptic histories of three African disturbances that developed into Atlantic hurricanes. Mon. Wea. Rev., 97, 256–276.

    • Search Google Scholar
    • Export Citation

  • Davis, C. A., and L. F. Bosart, 2003: Baroclinically induced tropical cyclogenesis. Mon. Wea. Rev., 131, 2730–2747.

  • DeMaria, M., J. A. Knaff, and B. H. Connell, 2001: A tropical cyclone genesis parameter for the tropical Atlantic. Wea. Forecasting, 16, 219–233.

    • Search Google Scholar
    • Export Citation

  • Diaz, H. F., T. N. Carlson, and J. M. Prospero, 1976: A study of the structure and dynamics of the Saharan air layer over the northern equatorial Atlantic during BOMEX. NOAA/National Hurricane and Experimental Meteorology Laboratory Tech. Memo. ERL WMPO-32, 61 pp.

    • Search Google Scholar
    • Export Citation

  • Drazin, P. G., and R. S. Johnson, 1989: Solitons: An Introduction. Cambridge University Press, 226 pp.

  • Dunion, J. P., and C. S. Velden, 2004: The impact of the Saharan air layer on Atlantic tropical cyclone activity. Bull. Amer. Meteor. Soc., 85, 353–365.

    • Search Google Scholar
    • Export Citation

  • Dunkerton, T. J., M. T. Montgomery, and Z. Wang, 2009: Tropical cyclogenesis in a tropical wave critical layer: Easterly waves. Atmos. Chem. Phys., 9, 5587–5646.

    • Search Google Scholar
    • Export Citation

  • Fang, J., and F. Zhang, 2010: Initial development and genesis of Hurricane Dolly (2008). J. Atmos. Sci., 67, 655–672.

  • Frank, N. L., 1970: Atlantic tropical systems of 1969. Mon. Wea. Rev., 98, 307–314.

  • Fujiwhara, S., 1921: The mutual tendency towards symmetry of motion and its application as a principle in meteorology. Quart. J. Roy. Meteor. Soc., 47, 287–293.

    • Search Google Scholar
    • Export Citation

  • Goldenberg, S. B., and L. J. Shapiro, 1996: Physical mechanisms for the association of El Niño and West African rainfall with Atlantic major hurricane activity. J. Climate, 9, 1169–1187.

    • Search Google Scholar
    • Export Citation

  • Gray, W. M., 1968: Global view of the origin of tropical disturbances and storms. Mon. Wea. Rev., 96, 669–700.

  • Gray, W. M., 1998: The formation of tropical cyclones. Meteor. Atmos. Phys., 67, 37–69.

  • Hendricks, E. A., and M. T. Montgomery, 2006: Rapid scan views of convectively generated mesovortices in sheared Tropical Cyclone Gustav (2002). Wea. Forecasting, 21, 1041–1050.

    • Search Google Scholar
    • Export Citation

  • Holton, J. R., 2004: An Introduction to Dynamic Meteorology. 4th ed. Academic Press, 535 pp.

  • Hopsch, S. B., C. D. Thorncroft, and K. R. Tyle, 2010: Analysis of African easterly wave structures and their role in influencing tropical cyclogenesis. Mon. Wea. Rev., 138, 1399–1419.

    • Search Google Scholar
    • Export Citation

  • James, R. P., and P. M. Markowski, 2010: A numerical investigation of the effects of dry air aloft on deep convection. Mon. Wea. Rev., 138, 140–161.

    • Search Google Scholar
    • Export Citation

  • Jones, S. C., 1995: The evolution of vortices in vertical shear: Initially barotropic vortices. Quart. J. Roy. Meteor. Soc., 121, 821–851.

    • Search Google Scholar
    • Export Citation

  • Karyampudi V. M., and Coauthors, 1999: Validation of the Saharan dust plume conceptual model using lidar, Meteosat, and ECMWF data. Bull. Amer. Meteor. Soc., 80, 1045–1075.

    • Search Google Scholar
    • Export Citation

  • Kerns, B., and E. Zipser, 2009: Four years of tropical ERA-40 vorticity maxima tracks. Part II: Differences between developing and nondeveloping disturbances. Mon. Wea. Rev., 137, 2576–2591.

    • Search Google Scholar
    • Export Citation

  • McBride, J. L., and R. Zehr, 1981: Observational analysis of tropical cyclone formation. Part II: Comparison of non-developing versus developing systems. J. Atmos. Sci., 38, 1132–1151.

    • Search Google Scholar
    • Export Citation

  • McWilliams, J. C., 1984: The emergence of isolated coherent vortices in turbulent flow. J. Fluid Mech., 146, 21–43.

  • McWilliams, J. C., 2006: Fundamentals of Geophysical Fluid Dynamics. Cambridge University Press, 266 pp.

  • Montgomery, M. T., L. L. Lussier III, R. W. Moore, and Z. Wang, 2010a: The genesis of Typhoon Nuri as observed during the Tropical Cyclone Structure 2008 (TCS-08) field experiment – Part 1: The role of the easterly wave critical layer. Atmos. Chem. Phys., 10, 9879–9900.

    • Search Google Scholar
    • Export Citation

  • Montgomery, M. T., Z. Wang, and T. J. Dunkerton, 2010b: Intermediate and high resolution numerical simulations of the transition of a tropical wave critical layer to a tropical depression. Atmos. Chem. Phys., 10, 10 803–10 827.

    • Search Google Scholar
    • Export Citation

  • Montgomery, M. T., and Coauthors, 2012: The Pre-Depression Investigation of Cloud Systems in the Tropics (PREDICT) experiment: Scientific basis, new analysis tools, and some first results. Bull. Amer. Meteor. Soc., 93, 153–172.

    • Search Google Scholar
    • Export Citation

  • Pedlosky, J., 1987. Geophysical Fluid Dynamics. 2nd ed. Springer-Verlag, 710 pp.

  • Peng, M. S., B. Fu, T. Li, and D. E. Stevens, 2012: Developing versus nondeveloping disturbances for tropical cyclone formation. Part I: North Atlantic. Mon. Wea. Rev., 140, 1047–1066.

    • Search Google Scholar
    • Export Citation

  • Pytharoulis, I., and C. Thorncroft, 1999: The low-level structure of African easterly waves in 1995. Mon. Wea. Rev., 127, 2266–2280.

  • Raymond, D. J., and C. López Carrillo, 2010: The vorticity budget of developing Typhoon Nuri (2008). Atmos. Chem. Phys. Discuss., 10, 16 589–16 635, doi:10.5194/acpd-10-16589-2010.

    • Search Google Scholar
    • Export Citation

  • Reasor, P. D., M. T. Montgomery, and L. D. Grasso, 2004: A new look at the problem of tropical cyclones in vertical shear flow: Vortex resiliency. J. Atmos. Sci., 61, 3–22.

    • Search Google Scholar
    • Export Citation

  • Reed, R. J., D. C. Norquist, and E. E. Recker, 1977: The structure and properties of African wave disturbances as observed during phase III of GATE. Mon. Wea. Rev., 105, 317–333.

    • Search Google Scholar
    • Export Citation

  • Reed, R. J., A. Hollingsworth, W. A. Heckley, and F. Delsol, 1988a: An evaluation of the ECMWF operational system in analyzing and forecasting easterly wave disturbances over Africa and the tropical Atlantic. Mon. Wea. Rev., 116, 824–865.

    • Search Google Scholar
    • Export Citation

  • Reed, R. J., E. Klinker, and A. Hollingsworth, 1988b: The structure and characteristics of African easterly wave disturbances as determined from the ECMWF Operational Analysis/Forecast System. Meteor. Atmos. Phys., 38, 22–33.

    • Search Google Scholar
    • Export Citation

  • Reznik, G. M., and W. K. Dewar, 1994: An analytical theory of distributed axisymmetric barotropic vortices on the β plane. J. Fluid Mech., 269, 301–321.

    • Search Google Scholar
    • Export Citation

  • Ross, R. S., T. N. Krishnamurti, S. Pattnaik, and A. Simon, 2009: Energy transformation and diabatic processes in developing and nondeveloping African easterly waves observed during the NAMMA project of 2006. Wea. Forecasting, 24, 1524–1548.

    • Search Google Scholar
    • Export Citation

  • Smith, R. K., and W. Ulrich, 1993: Vortex motion in relation to the absolute vorticity gradient of the environment. Quart. J. Roy. Meteor. Soc., 119, 207–215.

    • Search Google Scholar
    • Export Citation

  • Smith, R. K., W. Ulrich, and G. Dietachmayer, 1990: A numerical study of tropical cyclone motion using a barotropic model. Part I. The role of vortex asymmetries. Quart. J. Roy. Meteor. Soc., 116, 337–362.

    • Search Google Scholar
    • Export Citation

  • Thorncroft, C. D., and B. J. Hoskins, 1994: An idealized study of African easterly waves. I: A linear view. Quart. J. Roy. Meteor. Soc., 120, 953–982.

    • Search Google Scholar
    • Export Citation

  • Vizy, E. K., and K. H. Cook, 2009: Tropical storm development from African easterly waves in the eastern Atlantic: A comparison of two successive waves using a regional model as part of NASA AMMA 2006. J. Atmos. Sci., 66, 3313–3334.

    • Search Google Scholar
    • Export Citation

  • Wang, Z., M. T. Montgomery, and T. J. Dunkerton, 2009: A dynamically-based method for forecasting tropical cyclogenesis location in the Atlantic sector using global model products. Geophys. Res. Lett., 36, L03801, doi:10.1029/2008GL035586.

    • Search Google Scholar
    • Export Citation

  • Wang, Z., M. T. Montgomery, and T. J. Dunkerton, 2010a: Genesis of pre–Hurricane Felix (2007). Part I: The Role of the wave critical layer. J. Atmos. Sci., 67, 1711–1729.

    • Search Google Scholar
    • Export Citation

  • Wang, Z., M. T. Montgomery, and T. J. Dunkerton, 2010b: Genesis of pre–Hurricane Felix (2007). Part II: Warm core formation, precipitation evolution, and predictability. J. Atmos. Sci., 67, 1730–1744.

    • Search Google Scholar
    • Export Citation

  • Weiss, J., 1991: The dynamics of enstrophy transfer in two-dimensional hydrodynamics. Physica D, 48, 273–294.

  • Wimmers, A. J., and C. S. Velden, 2007: MIMIC: A new approach to visualizing satellite microwave imagery of tropical cyclones. Bull. Amer. Meteor. Soc., 88, 1187–1196.

    • Search Google Scholar
    • Export Citation

  • Zawislak, J., and E. J. Zipser, 2010: Observations of seven African easterly waves in the east Atlantic during 2006. J. Atmos. Sci., 67, 26–43.

    • Search Google Scholar
    • Export Citation

  • Zipser, E. J., and Coauthors, 2009: The Saharan air layer and the fate of African easterly waves—NASA’s AMMA field study of tropical cyclogenesis. Bull. Amer. Meteor. Soc., 90, 1137–1156.

    • Search Google Scholar
    • Export Citation
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