Shear-Relative Asymmetries in Tropical Cyclone Eyewall Slope

Andrew T. Hazelton Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida

Search for other papers by Andrew T. Hazelton in
Current site
Google Scholar
PubMed
Close
,
Robert Rogers NOAA/AOML/Hurricane Research Division, Miami, Florida

Search for other papers by Robert Rogers in
Current site
Google Scholar
PubMed
Close
, and
Robert E. Hart Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida

Search for other papers by Robert E. Hart in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Recent studies have analyzed the azimuthal mean slope of the tropical cyclone (TC) eyewall. This study looks at the shear-relative azimuthal variability of different metrics of eyewall slope: the 20-dBZ surface, the radius of maximum wind (RMW), and an angular momentum (M) surface passing through the RMW. The data used are Doppler radar composites from the NOAA Hurricane Research Division (HRD). This study examines 34 TCs, with intensities ranging from 3 to 75 m s−1 and shear magnitudes ranging from 0 to 10 m s−1. Calculation of the mean slope in each quadrant for all cases shows that RMW slope has the strongest asymmetry, with downshear slope larger than upshear in 62% of cases. Slopes of momentum surfaces and dBZ surfaces are also greater downshear in some cases (65% for M and 47% for dBZ), but there is more variance than in the RMW slope. The azimuthal phase of maximum slope occurs most often downshear, particularly downshear left, consistent with the depiction of a mean vortex tilt approximately 10° left of shear. Filtering the cases into high and low shear illustrates that the tendency for greater slope downshear is magnified for high-shear cases. In addition, although the dBZ slope shows less shear-relative signal overall, the difference between the dBZ slope and momentum slope is an important factor in distinguishing between strengthening and weakening or steady TCs. Intensifying TCs tend to have dBZ surfaces that are more upright than M surfaces. Further investigation of these results will help to illustrate the ways in which vertical shear can play a role in altering the structure of the TC core region.

Corresponding author address: Andrew Hazelton, Department of Earth, Ocean, and Atmospheric Science, Florida State University, 404 Love Bldg., Tallahassee, FL 32306-4520. E-mail: ath09c@my.fsu.edu

Abstract

Recent studies have analyzed the azimuthal mean slope of the tropical cyclone (TC) eyewall. This study looks at the shear-relative azimuthal variability of different metrics of eyewall slope: the 20-dBZ surface, the radius of maximum wind (RMW), and an angular momentum (M) surface passing through the RMW. The data used are Doppler radar composites from the NOAA Hurricane Research Division (HRD). This study examines 34 TCs, with intensities ranging from 3 to 75 m s−1 and shear magnitudes ranging from 0 to 10 m s−1. Calculation of the mean slope in each quadrant for all cases shows that RMW slope has the strongest asymmetry, with downshear slope larger than upshear in 62% of cases. Slopes of momentum surfaces and dBZ surfaces are also greater downshear in some cases (65% for M and 47% for dBZ), but there is more variance than in the RMW slope. The azimuthal phase of maximum slope occurs most often downshear, particularly downshear left, consistent with the depiction of a mean vortex tilt approximately 10° left of shear. Filtering the cases into high and low shear illustrates that the tendency for greater slope downshear is magnified for high-shear cases. In addition, although the dBZ slope shows less shear-relative signal overall, the difference between the dBZ slope and momentum slope is an important factor in distinguishing between strengthening and weakening or steady TCs. Intensifying TCs tend to have dBZ surfaces that are more upright than M surfaces. Further investigation of these results will help to illustrate the ways in which vertical shear can play a role in altering the structure of the TC core region.

Corresponding author address: Andrew Hazelton, Department of Earth, Ocean, and Atmospheric Science, Florida State University, 404 Love Bldg., Tallahassee, FL 32306-4520. E-mail: ath09c@my.fsu.edu
Save
  • Bell, M. M., M. T. Montgomery, and W. Lee, 2012: An axisymmetric view of concentric eyewall evolution in Hurricane Rita (2005). J. Atmos. Sci., 69, 24142432, doi:10.1175/JAS-D-11-0167.1.

    • Search Google Scholar
    • Export Citation
  • Black, M. L., J. F. Gamache, F. D. Marks, C. E. Samsury, and H. Willoughby, 2002: Eastern Pacific Hurricanes Jimena of 1991 and Olivia of 1994: The effect of vertical shear on structure and intensity. Mon. Wea. Rev., 130, 22912312, doi:10.1175/1520-0493(2002)130<2291:EPHJOA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Black, R. A., H. B. Bluestein, and M. L. Black, 1994: Unusually strong vertical motions in a Caribbean hurricane. Mon. Wea. Rev., 122, 27222739, doi:10.1175/1520-0493(1994)122<2722:USVMIA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Chen, H., and D. Zhang, 2013: On the rapid intensification of Hurricane Wilma (2005). Part II: Convective bursts and the upper-level warm core. J. Atmos. Sci., 70, 146162, doi:10.1175/JAS-D-12-062.1.

    • Search Google Scholar
    • Export Citation
  • Chen, S., J. A. Knaff, and F. D. Marks Jr., 2006: Effects of vertical wind shear and storm motion on tropical cyclone rainfall asymmetries deduced from TRMM. Mon. Wea. Rev., 134, 31903208, doi:10.1175/MWR3245.1.

    • Search Google Scholar
    • Export Citation
  • Corbosiero, K. L., and J. Molinari, 2002: The effects of vertical wind shear on the distribution of convection in tropical cyclones. Mon. Wea. Rev., 130, 21102123, doi:10.1175/1520-0493(2002)130<2110:TEOVWS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Corbosiero, K. L., and J. Molinari, 2003: The relationship between storm motion, vertical wind shear, and convective asymmetries in tropical cyclones. J. Atmos. Sci., 60, 366376, doi:10.1175/1520-0469(2003)060<0366:TRBSMV>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Corbosiero, K. L., J. Molinari, and M. L. Black, 2005: The structure and intensification of Hurricane Elena (1985). Part I: Symmetric intensification. Mon. Wea. Rev., 133, 29052921, doi:10.1175/MWR3010.1.

    • Search Google Scholar
    • Export Citation
  • DeHart, J., R. Houze, and R. Rogers, 2014: Quadrant distribution of tropical cyclone inner-core kinematics in relation to environmental shear. J. Atmos. Sci., 71, 27132732, doi:10.1175/JAS-D-13-0298.1.

    • Search Google Scholar
    • Export Citation
  • DeMaria, M., and J. Kaplan, 1994: A Statistical Hurricane Intensity Prediction Scheme (SHIPS) for the Atlantic basin. Wea. Forecasting, 9, 209220, doi:10.1175/1520-0434(1994)009<0209:ASHIPS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Eastin, M. D., W. M. Gray, and P. G. Black, 2005: Buoyancy of convective vertical motions in the inner core of intense hurricanes. Part II: Case studies. Mon. Wea. Rev., 133, 209227, doi:10.1175/MWR-2849.1.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K. A., 1986: An air–sea interaction theory for tropical cyclones. Part I: Steady-state maintenance. J. Atmos. Sci., 43, 585604, doi:10.1175/1520-0469(1986)043<0585:AASITF>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K. A., 1988: The maximum intensity of hurricanes. J. Atmos. Sci., 45, 11431155, doi:10.1175/1520-0469(1988)045<1143:TMIOH>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Frank, W. M., and E. A. Ritchie, 2001: Effects of vertical wind shear on the intensity and structure of numerically simulated hurricanes. Mon. Wea. Rev., 129, 22492269, doi:10.1175/1520-0493(2001)129<2249:EOVWSO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Gamache, J. F., 1997: Evaluation of a fully three-dimensional variational Doppler analysis technique. Preprints, 28th Conf. on Radar Meteorology, Austin, TX, Amer. Meteor. Soc., 422423.

  • Hack, J. J., and W. H. Schubert, 1986: Nonlinear response of atmospheric vortices to heating by organized cumulus convection. J. Atmos. Sci., 43, 15591573, doi:10.1175/1520-0469(1986)043<1559:NROAVT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Halverson, J. B., J. Simpson, G. Heymsfield, H. Pierce, T. Hock, and L. Ritchie, 2006: Warm core structure of Hurricane Erin diagnosed from high altitude dropsondes during CAMEX-4. J. Atmos. Sci., 63, 309324, doi:10.1175/JAS3596.1.

    • Search Google Scholar
    • Export Citation
  • Hazelton, A. T., and R. E. Hart, 2013: Hurricane eyewall slope as determined from airborne radar reflectivity data: Composites and case studies. Wea. Forecasting, 28, 368386, doi:10.1175/WAF-D-12-00037.1.

    • Search Google Scholar
    • Export Citation
  • Hendricks, E. A., W. H. Schubert, Y.-H. Chen, H.-C. Kuo, and M. S. Peng, 2014: Hurricane eyewall evolution in a forced shallow-water model. J. Atmos. Sci., 71, 16231643, doi:10.1175/JAS-D-13-0303.1.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., F. D. Marks Jr., and R. A. Black, 1992: Dual-aircraft investigation of the inner core of Hurricane Norbert. Part II: Mesoscale distribution of ice particles. J. Atmos. Sci., 49, 943963, doi:10.1175/1520-0469(1992)049<0943:DAIOTI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Jones, S. C., 1995: The evolution of vortices in vertical shear. I: Initially barotropic vortices. Quart. J. Roy. Meteor. Soc., 121, 821851, doi:10.1002/qj.49712152406.

    • Search Google Scholar
    • Export Citation
  • Jones, S. C., 2000: The evolution of vortices in vertical shear. III: Baroclinic vortices. Quart. J. Roy. Meteor. Soc., 126, 31613185, doi:10.1002/qj.49712657009.

    • Search Google Scholar
    • Export Citation
  • Jones, S. C., 2004: On the ability of dry tropical-cyclone-like vortices to withstand vertical shear. J. Atmos. Sci., 61, 114119, doi:10.1175/1520-0469(2004)061<0114:OTAODT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Jorgensen, D. P., 1984: Mesoscale and convective-scale structure of mature hurricanes. Part I: General observations by research aircraft. J. Atmos. Sci., 41, 12681285, doi:10.1175/1520-0469(1984)041<1268:MACSCO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Kepert, J. D., 2006: Observed boundary layer wind structure and balance in the hurricane core. Part II: Hurricane Mitch. J. Atmos. Sci., 63, 21942211, doi:10.1175/JAS3746.1.

    • Search Google Scholar
    • Export Citation
  • Marks, F. D., 1985: Evolution of the structure of precipitation in Hurricane Allen (1980). Mon. Wea. Rev., 113, 909930, doi:10.1175/1520-0493(1985)113<0909:EOTSOP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Marks, F. D., and R. A. Houze Jr., 1987: Inner core structure of Hurricane Alicia from airborne Doppler radar observations. J. Atmos. Sci., 44, 12961317, doi:10.1175/1520-0469(1987)044<1296:ICSOHA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • National Hurricane Center, cited 2014: Automated Tropical Cyclone Forecast Archive. [Available online at http://ftp.nhc.noaa.gov/atcf/archive/.]

  • Pendergrass, A. G., and H. E. Willoughby, 2009: Diabatically induced secondary flows in tropical cyclones. Part I: Quasi-steady forcing. Mon. Wea. Rev., 137, 805821, doi:10.1175/2008MWR2657.1.

    • Search Google Scholar
    • Export Citation
  • Reasor, P. D., and M. T. Montgomery, 2001: Three-dimensional alignment and corotation of weak, TC-like vortices via linear vortex Rossby waves. J. Atmos. Sci., 58, 2306–2330, doi:10.1175/1520-0469(2001)058<2306:TDAACO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Reasor, P. D., and M. D. Eastin, 2012: Rapidly-intensifying Hurricane Guillermo (1997). Part II: Resilience in shear. Mon. Wea. Rev., 140, 425444, doi:10.1175/MWR-D-11-00080.1.

    • Search Google Scholar
    • Export Citation
  • Reasor, P. D., M. T. Montgomery, F. D. Marks, and J. F. Gamache, 2000: Low-wavenumber structure and evolution of the hurricane inner-core observed by airborne Dual-Doppler radar. Mon. Wea. Rev., 128, 16531680, doi:10.1175/1520-0493(2000)128<1653:LWSAEO>2.0.CO;2.

    • 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, 322, doi:10.1175/1520-0469(2004)061<0003:ANLATP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Reasor, P. D., M. D. Eastin, and J. F. Gamache, 2009: Rapidly intensifying Hurricane Guillermo (1997). Part I: Low-wavenumber structure and evolution. Mon. Wea. Rev., 137, 603–631, doi:10.1175/2008MWR2487.1.

    • Search Google Scholar
    • Export Citation
  • Reasor, P. D., R. Rogers, and S. Lorsolo, 2013: Environmental flow impacts on tropical cyclone structure diagnosed from airborne Doppler radar composites. Mon. Wea. Rev., 141, 29492969, doi:10.1175/MWR-D-12-00334.1.

    • Search Google Scholar
    • Export Citation
  • Riemer, M., M. T. Montgomery, and M. E. Nicholls, 2010: A new paradigm for intensity modification of tropical cyclones: Thermodynamic impact of vertical wind shear on the inflow layer. Atmos. Chem. Phys., 10, 31633188, doi:10.5194/acp-10-3163-2010.

    • Search Google Scholar
    • Export Citation
  • Rogers, R. F., and E. Uhlhorn, 2008: Observations of the structure and evolution of surface and flight-level wind asymmetries in Hurricane Rita (2005). Geophys. Res. Lett.,35, L22811, doi:10.1029/2008GL034774.

  • Rogers, R. F., F. D. Marks Jr., and T. Marchok, 2009: Tropical cyclone rainfall. Encyclopedia of Hydrological Sciences, M. G. Anderson, Ed., John Wiley & Sons, 1–22, doi:10.1002/0470848944.hsa030.

  • Rogers, R. F., S. Lorsolo, P. Reasor, J. Gamache, and F. Marks, 2012: Multiscale analysis of tropical cyclone kinematic structure from airborne Doppler radar composites. Mon. Wea. Rev., 140, 7799, doi:10.1175/MWR-D-10-05075.1.

    • Search Google Scholar
    • Export Citation
  • Rogers, R. F., P. Reasor, and S. Lorsolo, 2013: Airborne Doppler observations of the inner-core structural differences between intensifying and steady-state tropical cyclones. Mon. Wea. Rev., 141, 29702991, doi:10.1175/MWR-D-12-00357.1.

    • Search Google Scholar
    • Export Citation
  • Rogers, R. F., P. Reasor, and J. Zhang, 2014: Multiscale structure and evolution of Hurricane Earl (2010) during rapid intensification. Mon. Wea. Rev., in press.

    • Search Google Scholar
    • Export Citation
  • Schecter, D. A., M. T. Montgomery, and P. D. Reasor, 2002: A theory for the vertical alignment of a quasigesotrophic vortex. J. Atmos. Sci., 59, 150168, doi:10.1175/1520-0469(2002)059<0150:ATFTVA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Schubert, W. H., and J. J. Hack, 1982: Inertial stability and tropical cyclone development. J. Atmos. Sci., 39, 16871697, doi:10.1175/1520-0469(1982)039<1687:ISATCD>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Shapiro, L. J., and H. E. Willoughby, 1982: The response of balanced hurricanes to local sources of heat and momentum. J. Atmos. Sci., 39, 378394, doi:10.1175/1520-0469(1982)039<0378:TROBHT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Shea, D. J., and W. M. Gray, 1973: The hurricane’s inner core region. Part I: Symmetric and asymmetric structure. J. Atmos. Sci., 30, 15441564, doi:10.1175/1520-0469(1973)030<1544:THICRI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Stern, D. P., and D. S. Nolan, 2009: Reexamining the vertical structure of tangential winds in tropical cyclones: Observations and theory. J. Atmos. Sci., 66, 35793600, doi:10.1175/2009JAS2916.1.

    • Search Google Scholar
    • Export Citation
  • Stern, D. P., J. R. Brisbois, and D. S. Nolan, 2014: An expanded dataset of hurricane eyewall sizes and slopes. J. Atmos. Sci., 71, 27472762, doi:10.1175/JAS-D-13-0302.1.

    • Search Google Scholar
    • Export Citation
  • Uhlhorn, E. W., B. Klotz, T. Vukicevic, P. Reasor, and R. F. Rogers, 2014: Observed hurricane wind speed asymmetries and relationships to motion and environmental shear. Mon. Wea. Rev., 142, 12901311, doi:10.1175/MWR-D-13-00249.1.

    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., J. A. Clos, and M. G. Shoreibah, 1982: Concentric eye walls, secondary wind maxima, and the evolution of the hurricane vortex. J. Atmos. Sci., 39, 395411, doi:10.1175/1520-0469(1982)039<0395:CEWSWM>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 3094 2685 38
PDF Downloads 318 85 7