• Bergot, T., G. Hello, and A. Joly, 1999: Adaptive observations: A feasibility study. Mon. Wea. Rev., 127 , 743765.

  • Bishop, C. H., B. J. Etherton, and S. J. Majumdar, 2001: Adaptive sampling with the ensemble transform Kalman filter. Part I: Theoretical aspects. Mon. Wea. Rev., 129 , 420436.

    • Search Google Scholar
    • Export Citation
  • Bloomfield, P., 2000: Fourier Analysis of Time Series: An Introduction. 2d ed. Wiley-Interscience, 261 pp.

  • Buizza, R., and P. Chessa, 2002: Prediction of the U.S. storm of 24–26 January 2000 with the ECMWF Ensemble Prediction System. Mon. Wea. Rev., 130 , 15311551.

    • Search Google Scholar
    • Export Citation
  • Chang, E. K. M., 2000: Wave packets and life cycles of troughs in the upper troposphere: Examples from the Southern Hemisphere summer season of 1984/85. Mon. Wea. Rev., 128 , 2550.

    • Search Google Scholar
    • Export Citation
  • Chang, E. K. M., and D. B. Yu, 1999: Characteristics of wave packets in the upper troposphere. Part I: Northern Hemisphere winter. J. Atmos. Sci., 56 , 17081728.

    • Search Google Scholar
    • Export Citation
  • Charney, J. G., 1949: On a physical basis for numerical prediction of large-scale motions in the atmosphere. J. Meteor., 6 , 371385.

  • Gabor, D., 1946: Theory of communication. J. IEEE, 93 , 429457.

  • Gelaro, R., R. H. Langland, G. D. Rohaly, and T. E. Rossmond, 1999: An assessment of the singular-vector approach to target observations using the FASTEX dataset. Quart. J. Roy. Meteor. Soc., 125 , 32993328.

    • Search Google Scholar
    • Export Citation
  • Hovmöller, E., 1949: The trough-and-ridge diagram. Tellus, 1 , 6266.

  • Laine, A., and J. Fan, 1996: Frame representations for texture segmentation. IEEE Trans. Image Process., 5 , 771780.

  • Langland, R. H., M. A. Shapiro, and R. Gelaro, 2002: Initial condition sensitivity and error growth in forecasts of the 25 January 2000 East Coast snowstorm. Mon. Wea. Rev., 130 , 957974.

    • Search Google Scholar
    • Export Citation
  • Lee, S., and I. M. Held, 1993: Baroclinic wave packets in models and observations. J. Atmos. Sci., 50 , 14131428.

  • Oppenheim, A., and R. Shafer, 1975: Digital Signal Processing. Prentice Hall, 585 pp.

  • Orlanski, I., and J. P. Sheldon, 1993: A case of downstream baroclinic development over western North America. Mon. Wea. Rev., 121 , 29292950.

    • Search Google Scholar
    • Export Citation
  • Palmer, T. N., R. Gelaro, J. Barkmeijer, and R. Buizza, 1998: Singular vectors, metrics, and adaptive observations. J. Atmos. Sci., 55 , 633653.

    • Search Google Scholar
    • Export Citation
  • Pedlosky, J., 1987: Geophysical Fluid Dynamics. 2d ed. Springer-Verlag, 710 pp.

  • Persson, A., 2000: Synoptic–dynamic diagnosis of medium range weather forecast systems. Proc. of the Seminars on Diagnosis of Models and Data Assimilation Systems, Reading, United Kingdom, ECMWF, 123–137.

    • Search Google Scholar
    • Export Citation
  • Phillips, N. A., 1990: Dispersion Processes in Large-Scale Weather Prediction. WMO-No. 700, World Meteorological Organization, 126 pp.

  • Pu, Z-X., and E. Kalnay, 1999: Targeting observations with the quasi-inverse linear and adjoint NCEP global models: Performance during FASTEX. Quart. J. Roy. Meteor. Soc., 125 , 33293337.

    • Search Google Scholar
    • Export Citation
  • Rossby, C-G., 1945: On the propagation of frequencies and energy in certain types of oceanic and atmospheric waves. J. Meteor., 2 , 187204.

    • Search Google Scholar
    • Export Citation
  • Rossby, C-G., 1949: On the dispersion of planetary waves in a barotropic atmosphere. Tellus, 1 , 5458.

  • Snyder, C., 1996: Summary of an informal workshop on adaptive observations and FASTEX. Bull. Amer. Meteor. Soc., 77 , 953961.

  • Swanson, K., and R. T. Pierrehumbert, 1994: Nonlinear wave packet evolution on a baroclinically unstable jet. J. Atmos. Sci., 51 , 384396.

    • Search Google Scholar
    • Export Citation
  • Szunyogh, I., Z. Toth, K. A. Emanuel, C. H. Bishop, C. Snyder, R. E. Morss, J. Woolen, and T. Marchok, 1999: Ensemble-based targeting experiments during FASTEX: The effect of dropsonde data from the Lear jet. Quart. J. Roy. Meteor. Soc., 125 , 31893218.

    • Search Google Scholar
    • Export Citation
  • Szunyogh, I., Z. Toth, R. E. Morss, S. J. Majumdar, B. J. Etherton, and C. H. Bishop, 2000: The effect of targeted dropsonde observations during the 1999 Winter Storm Reconnaissance Program. Mon. Wea. Rev., 128 , 35203537.

    • Search Google Scholar
    • Export Citation
  • Szunyogh, I., Z. Toth, A. V. Zimin, S. J. Majumdar, and A. Persson, 2002: On the propagation of the effect of targeted observations: The 2000 Winter Storm Reconnaissance Program. Mon. Wea. Rev., 130 , 11441165.

    • Search Google Scholar
    • Export Citation
  • Yeh, T., 1949: On energy dispersion in the atmosphere. J. Meteor., 6 , 116.

  • Zhang, F., C. Snyder, and R. Rotunno, 2002: Mesoscale predictability of the “surprise” snowstorm of 24–25 January 2000. Mon. Wea. Rev., 130 , 16171632.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 440 303 19
PDF Downloads 280 189 9

Extracting Envelopes of Rossby Wave Packets

View More View Less
  • 1 Department of Physics, University of Maryland, College Park, Maryland
  • | 2 Institute for Physical Science and Technology, and Department of Meteorology, University of Maryland, College Park, Maryland
  • | 3 Institute for Physical Science and Technology, Department of Mathematics, and Department of Meteorology, University of Maryland, College Park, Maryland
  • | 4 Institute for Physical Science and Technology, and Department of Mathematics, University of Maryland, College Park, Maryland
  • | 5 Institute for Research in Electronics and Applied Physics, Department of Physics, and Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland
Restricted access

Abstract

Packets of Rossby waves play an important role in the transfer of kinetic energy in the extratropics. The ability to locate, track, and detect changes in the envelope of these wave packets is vital to detecting baroclinic downstream development, tracking the impact of the analysis errors in numerical weather forecasts, and analyzing the forecast effects of targeted weather observations. In this note, it is argued that a well-known technique of digital signal processing, which is based on the Hilbert transform, should be used for extracting the envelope of atmospheric wave packets. This technique is robust, simple, and computationally inexpensive. The superiority of the proposed algorithm over the complex demodulation technique (the only technique previously used for this purpose in atmospheric studies) is demonstrated by examples. The skill of the proposed algorithm is also demonstrated by tracking wave packets in operational weather analyses from the National Centers for Environmental Prediction (NCEP) and analyzing the effects of targeted observations from the 2000 Winter Storm Reconnaissance (WSR00) field program.

Corresponding author address: Aleksey V. Zimin, Dept. of Physics, University of Maryland, Physics Bldg., Box 240, College Park, MD 20742. Email: alekseyz@physics.umd.edu

Abstract

Packets of Rossby waves play an important role in the transfer of kinetic energy in the extratropics. The ability to locate, track, and detect changes in the envelope of these wave packets is vital to detecting baroclinic downstream development, tracking the impact of the analysis errors in numerical weather forecasts, and analyzing the forecast effects of targeted weather observations. In this note, it is argued that a well-known technique of digital signal processing, which is based on the Hilbert transform, should be used for extracting the envelope of atmospheric wave packets. This technique is robust, simple, and computationally inexpensive. The superiority of the proposed algorithm over the complex demodulation technique (the only technique previously used for this purpose in atmospheric studies) is demonstrated by examples. The skill of the proposed algorithm is also demonstrated by tracking wave packets in operational weather analyses from the National Centers for Environmental Prediction (NCEP) and analyzing the effects of targeted observations from the 2000 Winter Storm Reconnaissance (WSR00) field program.

Corresponding author address: Aleksey V. Zimin, Dept. of Physics, University of Maryland, Physics Bldg., Box 240, College Park, MD 20742. Email: alekseyz@physics.umd.edu

Save