The Experimental HWRF System: A Study on the Influence of Horizontal Resolution on the Structure and Intensity Changes in Tropical Cyclones Using an Idealized Framework

Sundararaman G. Gopalakrishnan NOAA/Hurricane Research Division/Atlantic Oceanographic Meteorological Laboratory, Miami, Florida

Search for other papers by Sundararaman G. Gopalakrishnan in
Current site
Google Scholar
PubMed
Close
,
Frank Marks Jr. NOAA/Hurricane Research Division/Atlantic Oceanographic Meteorological Laboratory, Miami, Florida

Search for other papers by Frank Marks Jr. in
Current site
Google Scholar
PubMed
Close
,
Xuejin Zhang Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, Florida

Search for other papers by Xuejin Zhang in
Current site
Google Scholar
PubMed
Close
,
Jian-Wen Bao NOAA/Earth System Research Laboratory, Boulder, Colorado

Search for other papers by Jian-Wen Bao in
Current site
Google Scholar
PubMed
Close
,
Kao-San Yeh Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, Florida

Search for other papers by Kao-San Yeh in
Current site
Google Scholar
PubMed
Close
, and
Robert Atlas Atlantic Oceanographic Meteorological Laboratory, Miami, Florida

Search for other papers by Robert Atlas in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Forecasting intensity changes in tropical cyclones (TCs) is a complex and challenging multiscale problem. While cloud-resolving numerical models using a horizontal grid resolution of 1–3 km are starting to show some skill in predicting the intensity changes in individual cases, it is not clear at this time what may be a reasonable horizontal resolution for forecasting TC intensity changes on a day-to-day-basis. The Experimental Hurricane Weather Research and Forecasting System (HWRFX) was used within an idealized framework to gain a fundamental understanding of the influence of horizontal grid resolution on the dynamics of TC vortex intensification in three dimensions. HWFRX is a version of the National Centers for Environmental Prediction (NCEP) Hurricane Weather Research and Forecasting (HWRF) model specifically adopted and developed jointly at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) and Earth System Research Laboratory (ESRL) for studying the intensity change problem at a model grid resolution of about 3 km. Based on a series of numerical experiments at the current operating resolution of about 9 km and at a finer resolution of about 3 km, it was found that improved resolution had very little impact on the initial spinup of the vortex. An initial axisymmetric vortex with a maximum wind speed of 20 m s−1 rapidly intensified to 50 m s−1 within about 24 h in either case. During the spinup process, buoyancy appears to have had a pivotal influence on the formation of the warm core and the subsequent rapid intensification of the modeled vortex. The high-resolution simulation at 3 km produced updrafts as large as 48 m s−1. However, these extreme events were rare, and this study indicated that these events may not contribute significantly to rapid deepening. Additionally, although the structure of the buoyant plumes may differ at 9- and 3-km resolution, interestingly, the axisymmetric structure of the simulated TCs exhibited major similarities. Specifically, the similarities included a deep inflow layer extending up to about 2 km in height with a tangentially averaged maximum inflow velocity of about 12–15 m s−1, vertical updrafts with an average velocity of about 2 m s−1, and a very strong outflow produced at both resolutions for a mature storm. It was also found in either case that the spinup of the primary circulation occurred not only due to the weak inflow above the boundary layer but also due to the convergence of vorticity within the boundary layer. Nevertheless, the mature phase of the storm’s evolution exhibited significantly different patterns of behavior at 9 and 3 km. While the minimum pressure at the end of 96 h was 934 hPa for the 9-km simulation, it was about 910 hPa for the 3-km run. The maximum tangential wind at that time showed a difference of about 10 m s−1. Several sensitivity experiments related to the initial vortex intensity, initial radius of the maximum wind, and physics were performed. Based on ensembles of simulations, it appears that radial advection of the tangential wind and, consequently, radial flux of vorticity become important forcing terms in the momentum budget of the mature storm. Stronger convergence in the boundary layer leads to a larger transport of moisture fluxes and, subsequently, a stronger storm at higher resolution.

Corresponding author address: S. G. Gopalakrishnan, AOML/HRD, 4301 Rickenbacker Cswy., Miami, FL 33149. E-mail: gopal@noaa.gov

Abstract

Forecasting intensity changes in tropical cyclones (TCs) is a complex and challenging multiscale problem. While cloud-resolving numerical models using a horizontal grid resolution of 1–3 km are starting to show some skill in predicting the intensity changes in individual cases, it is not clear at this time what may be a reasonable horizontal resolution for forecasting TC intensity changes on a day-to-day-basis. The Experimental Hurricane Weather Research and Forecasting System (HWRFX) was used within an idealized framework to gain a fundamental understanding of the influence of horizontal grid resolution on the dynamics of TC vortex intensification in three dimensions. HWFRX is a version of the National Centers for Environmental Prediction (NCEP) Hurricane Weather Research and Forecasting (HWRF) model specifically adopted and developed jointly at NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) and Earth System Research Laboratory (ESRL) for studying the intensity change problem at a model grid resolution of about 3 km. Based on a series of numerical experiments at the current operating resolution of about 9 km and at a finer resolution of about 3 km, it was found that improved resolution had very little impact on the initial spinup of the vortex. An initial axisymmetric vortex with a maximum wind speed of 20 m s−1 rapidly intensified to 50 m s−1 within about 24 h in either case. During the spinup process, buoyancy appears to have had a pivotal influence on the formation of the warm core and the subsequent rapid intensification of the modeled vortex. The high-resolution simulation at 3 km produced updrafts as large as 48 m s−1. However, these extreme events were rare, and this study indicated that these events may not contribute significantly to rapid deepening. Additionally, although the structure of the buoyant plumes may differ at 9- and 3-km resolution, interestingly, the axisymmetric structure of the simulated TCs exhibited major similarities. Specifically, the similarities included a deep inflow layer extending up to about 2 km in height with a tangentially averaged maximum inflow velocity of about 12–15 m s−1, vertical updrafts with an average velocity of about 2 m s−1, and a very strong outflow produced at both resolutions for a mature storm. It was also found in either case that the spinup of the primary circulation occurred not only due to the weak inflow above the boundary layer but also due to the convergence of vorticity within the boundary layer. Nevertheless, the mature phase of the storm’s evolution exhibited significantly different patterns of behavior at 9 and 3 km. While the minimum pressure at the end of 96 h was 934 hPa for the 9-km simulation, it was about 910 hPa for the 3-km run. The maximum tangential wind at that time showed a difference of about 10 m s−1. Several sensitivity experiments related to the initial vortex intensity, initial radius of the maximum wind, and physics were performed. Based on ensembles of simulations, it appears that radial advection of the tangential wind and, consequently, radial flux of vorticity become important forcing terms in the momentum budget of the mature storm. Stronger convergence in the boundary layer leads to a larger transport of moisture fluxes and, subsequently, a stronger storm at higher resolution.

Corresponding author address: S. G. Gopalakrishnan, AOML/HRD, 4301 Rickenbacker Cswy., Miami, FL 33149. E-mail: gopal@noaa.gov
Save
  • Bender, M. A., I. Ginis, R. E. Tuleya, B. Thomas, and T. Marchok, 2007: The operational GFDL coupled hurricane–ocean prediction system and a summary of its performance. Mon. Wea. Rev., 135, 39653989.

    • Search Google Scholar
    • Export Citation
  • Braun, S., and W.-K. Tao, 2000: Sensitivity of high-resolution simulations of Hurricane Bob (1991) to planetary boundary layer parameterizations. Mon. Wea. Rev., 128, 39413961.

    • Search Google Scholar
    • Export Citation
  • Eliassen, A., 1951: Slow thermally or frictionally controlled meridional circulation in a circular vortex. Astrophys. Norv., 5 (2), 1960.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K. A., 1997: Some aspects of hurricane inner-core dynamics and energetics. J. Atmos. Sci., 54, 10141026.

  • Emanuel, K. A., 2003: A century of scientific progress. Hurricane! Coping with Disaster, R. Simpson, R. Anthes, and M. Garstang, Eds., Special Publication, Vol. 55, Amer. Geophys. Union, 177–216.

    • Search Google Scholar
    • Export Citation
  • Fierro, A. O., R. F. Rogers, F. D. Marks, and D. S. Nolan, 2009: The impact of horizontal grid spacing on the microphysical and kinematic structures of strong tropical cyclones simulated with the WRF-ARW model. Mon. Wea. Rev., 137, 37173743.

    • Search Google Scholar
    • Export Citation
  • Gopalakrishnan, S. G., and R. Avissar, 2000: LES study of the impacts of land surface heterogeneity on dispersion in the convective boundary layer. J. Atmos. Sci., 57, 352371.

    • Search Google Scholar
    • Export Citation
  • Gopalakrishnan, S. G., and Coauthors, 2002: An operational multiscale atmospheric model with grid adaptivity for hurricane forecasting. Mon. Wea. Rev., 130, 18301847.

    • Search Google Scholar
    • Export Citation
  • Gopalakrishnan, S. G., Q. Liu, T. Marchok, D. Sheinin, N. Surgi, R. Tuleya, R. Yablonsky, and X. Zhang, 2010: Hurricane Weather and Research and Forecasting (HWRF) model scientific documentation. NOAA/NCAR/Development Tech Center, 75 pp. [Available online at http://www.dtcenter.org/HurrWRF/users/docs/scientific_documents/HWRF_final_2-2_cm.pdf.]

    • Search Google Scholar
    • Export Citation
  • Gray, W. M., E. Ruprecht, and R. Phelps, 1975: Relative humidity in tropical weather systems. Mon. Wea. Rev., 103, 685690.

  • Guinn, T. A., and W. H. Schubert, 1993: Hurricane spiral bands. J. Atmos. Sci., 50, 33803403.

  • Hawkins, H. F., and S. M. Imbembo, 1976: The structure of a small, intense hurricane, Inez (1966). Mon. Wea. Rev., 104, 418442.

  • Holland, G. J., 1997: The maximum potential intensity of tropical cyclones. J. Atmos. Sci., 54, 25192541.

  • Janjić, Z. I., 2003: A non-hydrostatic model based on a new approach. Meteor. Atmos. Phys., 82, 271285.

  • Janjić, Z. I., J. P. Gerrity Jr., and S. Nickovic, 2001: An alternative approach to nonhydrostatic modeling. Mon. Wea. Rev., 129, 11641178.

    • Search Google Scholar
    • Export Citation
  • Jorgensen, D. P., 1984: Mesoscale and convective scale characteristics of mature hurricanes. Part I: General observations by aircraft. J. Atmos. Sci., 41, 12681285.

    • Search Google Scholar
    • Export Citation
  • Kaplan, J., and M. DeMaria, 2003: Large-scale characteristics of rapidly intensifying tropical cyclones in the North Atlantic basin. Wea. Forecasting, 18, 10931108.

    • Search Google Scholar
    • Export Citation
  • Kaplan, J., M. DeMaria, and J. A. Knaff, 2010: A revised tropical cyclone rapid intensification index for the Atlantic and eastern North Pacific basins. Wea. Forecasting, 25, 220241.

    • Search Google Scholar
    • Export Citation
  • Kurihara, Y., 1975: Budget analysis of a tropical cyclone simulated in an axisymmetric numerical model. J. Atmos. Sci., 32, 2559.

  • Kurihara, Y., and R. E. Tuleya, 1974: Structure of a tropical cyclone developed in a three-dimensional numerical simulation model. J. Atmos. Sci., 31, 893919.

    • Search Google Scholar
    • Export Citation
  • Liu, Y., D.-L. Zhang, and M. K. Yau, 1999: A multiscale numerical study of Hurricane Andrew (1992). Part II: Kinematics and inner-core structures. Mon. Wea. Rev., 127, 25972616.

    • Search Google Scholar
    • Export Citation
  • Malkus, J. S., and H. Riehl, 1960: On the dynamics and energy transformations in steady-state hurricanes. Tellus, 12, 120.

  • Marks, F. D., Jr., and R. A. Houze Jr., 1987: Inner core structure of Hurricane Alicia from airborne Doppler radar observations. J. Atmos. Sci., 44, 12961317.

    • Search Google Scholar
    • Export Citation
  • Marks, F. D., Jr., R. A. Houze Jr., and J. F. Gamache, 1992: Dual-aircraft investigation of the inner core of the Hurricane Norbert. Part I: Kinematic structure. J. Atmos. Sci., 49, 919942.

    • Search Google Scholar
    • Export Citation
  • Montgomery, M. T., V. S. Nguyen, J. Persing, and R. K. Smith, 2009: Do tropical cyclones intensify by WISHE? Quart. J. Roy. Meteor. Soc., 135, 16971714.

    • Search Google Scholar
    • Export Citation
  • Nguyen, V. S., R. K. Smith, and M. T. Montgomery, 2008: Tropical-cyclone intensification and predictability in three dimensions. Quart. J. Roy. Meteor. Soc., 134, 563582.

    • Search Google Scholar
    • Export Citation
  • Ooyama, K. V., 1969: Numerical simulation of the life cycle of tropical cyclones. J. Atmos. Sci., 26, 340.

  • Ooyama, K. V., 1982: Conceptual evolution of the theory and modeling of the tropical cyclone. J. Meteor. Soc. Japan, 60, 369379.

  • Pan, H.-L., and W.-S. Wu, 1995: Implementing a mass flux convective parameterization package for the NMC Medium-Range Forecast model. NMC Office Note 409, 40 pp. [Available from NOAA/NWS/NCEP/Environmental Modeling Center, WWB, Rm. 207, Washington, DC 20233.]

    • Search Google Scholar
    • Export Citation
  • 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.

    • Search Google Scholar
    • Export Citation
  • Riehl, H., 1954: Tropical Meteorology. McGraw-Hill, 342 pp.

  • Ritchie, E. A., J. Simpson, W. T. Liu, J. Halverson, C. Velden, K. F. Brueske, and H. Pierce, 2003: Present day satellite technology for hurricane research. Hurricane! Coping with Disaster, R. Simpson, R. Anthes, and M. Garstang, Eds., Special Publication, Vol. 55, Amer. Geophys. Union, 249–289.

    • Search Google Scholar
    • Export Citation
  • Rogers, R., 2010: Convective-scale structure and evolution during a high-resolving simulation of tropical cyclone rapid intensification. J. Atmos. Sci., 67, 4470.

    • Search Google Scholar
    • Export Citation
  • Rotunno, R., and K. A. Emanuel, 1987: An air–sea interaction theory for tropical cyclones. Part II: Evolutionary study using a nonhydrostatic axisymmetric numerical model. J. Atmos. Sci., 44, 542561.

    • Search Google Scholar
    • Export Citation
  • Shen, W., R. E. Tuleya, and I. Ginis, 2000: A sensitivity study of the thermodynamic environment on GFDL model hurricane intensity: Implications for global warming. J. Climate, 13, 109121.

    • Search Google Scholar
    • Export Citation
  • Smith, R. K., 1980: Tropical cyclone eye dynamics. J. Atmos. Sci., 37, 12271232.

  • Smith, R. K., M. T. Montgomery, and S. H. Zhu, 2005: Buoyancy in tropical cyclones and other rotating atmospheric vortices. Dyn. Atmos. Oceans, 40, 189208.

    • Search Google Scholar
    • Export Citation
  • Smith, R. K., M. T. Montgomery, and S. Vogl, 2008: A critique of Emanuel’s hurricane model and potential intensity theory. Quart. J. Roy. Meteor. Soc., 134, 551561.

    • Search Google Scholar
    • Export Citation
  • Smith, R. K., M. T. Montgomery, and N. V. Sang, 2009: Tropical cyclone spin-up revisited. Quart. J. Roy. Meteor. Soc., 135, 13211335.

    • Search Google Scholar
    • Export Citation
  • Sundqvist, H., 1970: Numerical simulation of the development of tropical cyclones with a ten-level model. Part II. Tellus, 22, 504510.

    • Search Google Scholar
    • Export Citation
  • Tuleya, R. E., and Y. Kurihara, 1975: The energy and angular momentum budgets of a three-dimensional tropical cyclone model. J. Atmos. Sci., 32, 287301.

    • Search Google Scholar
    • Export Citation
  • Tuleya, R. E., and Y. Kurihara, 1978: A numerical simulation of the landfall of tropical cyclones. J. Atmos. Sci., 35, 242257.

  • Tuleya, R. E., and Y. Kurihara, 1982: A note on the sea surface temperature sensitivity of a numerical model of tropical storm genesis. Mon. Wea. Rev., 110, 20632069.

    • Search Google Scholar
    • Export Citation
  • Wang, Y., 1995: On an inverse balance equation in sigma-coordinates for model initialization. Mon. Wea. Rev., 123, 482488.

  • Wang, Y., 2002a: An explicit simulation of tropical cyclones with a triply nested movable mesh primitive equations model-TCM3. Part II: Model refinements and sensitivity to cloud microphysics parameterization. Mon. Wea. Rev., 130, 30223036.

    • Search Google Scholar
    • Export Citation
  • Wang, Y., 2002b: Vortex Rossby waves in a numerically simulated tropical cyclone. Part I: Overall structure, potential vorticity, and kinetic energy budgets. J. Atmos. Sci., 59, 12131238.

    • Search Google Scholar
    • Export Citation
  • Wang, Y., 2002c: Vortex Rossby waves in a numerically simulated tropical cyclone. Part II: The role in tropical cyclone structure and intensity changes. J. Atmos. Sci., 59, 12391262.

    • Search Google Scholar
    • Export Citation
  • Wang, Y., 2009: How do outer spiral rainbands affect tropical cyclone structure and intensity? J. Atmos. Sci., 66, 12501273.

  • Willoughby, H. E., 1978: A possible mechanism for the formation of hurricane rainbands. J. Atmos. Sci., 35, 838848.

  • Willoughby, H. E., 1979: Forced secondary circulations in hurricanes. J. Geophys. Res., 84, 31733183.

  • Willoughby, H. E., 1990a: Temporal changes of the primary circulation in tropical cyclones. J. Atmos. Sci., 47, 242264.

  • Willoughby, H. E., 1990b: Gradient balance in tropical cyclones. J. Atmos. Sci., 47, 265274.

  • Willoughby, H. E., 2009: Diabatically induced secondary flows in tropical cyclones. Part II: Periodic forcing. Mon. Wea. Rev., 137, 822835.

    • Search Google Scholar
    • Export Citation
  • Willoughby, H. E., H.-L. Jin, S. J. Lord, and J. M. Piotrowicz, 1984: Hurricane structure and evolution as simulated by an axisymmetric, nonhydrostatic numerical model. J. Atmos. Sci., 41, 11691186.

    • Search Google Scholar
    • Export Citation
  • Yamasaki, M., 1977: A preliminary experiment of the tropical cyclone without parameterizing the effects of cumulus convection. J. Meteor. Soc. Japan, 55, 1130.

    • Search Google Scholar
    • Export Citation
  • Zhang, D.-L., Y. Liu, and M. K. Yau, 2001: A multiscale numerical study of Hurricane Andrew (1992). Part IV: Unbalanced flows. Mon. Wea. Rev., 129, 92107.

    • Search Google Scholar
    • Export Citation
  • Zhang, X., T. S. Quirino, K. S. Yeh, S. Gopalakrishnan, F. D. Marks Jr., and S. B. Goldenberg, 2011: Toward improving hurricane forecast with high resolution model. Comput. Sci. Eng., 13, 1321.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 901 151 11
PDF Downloads 494 110 9