• Banner, M. L., 1990: Equilibrium spectra of wind waves. J. Phys. Oceanogr.,20, 966–984.

  • ——, and I. R. Young, 1994: Modeling spectral dissipation in the evolution of wind waves. Part I: Assessment of existing model performance. J. Phys. Oceanogr.,24, 1550–1571.

  • Benoit, M., P. Frigaard, and H. A. Schaffer, 1997: Analyzing multidirectional wave spectra: A tentative classification of available methods. Proc. Seminar on Multidirectional Waves and their Interaction with Structures, San Francisco, CA, International Assembly of Hydraulic Research, 131–158.

  • Cote, L. J., and Coauthors, 1960: The directional spectrum of a wind generated sea as determined from data obtained by the Stereo Wave Observation Project. Meteorological Papers, Vol. 2, University Publishers Tech. Rep., New York University, 88 pp.

  • Donelan, M. A., J. Hamilton, and W. H. Hui, 1985: Directional spectra of wind-generated waves. Philos. Trans. Roy. Soc. London,A315, 509–562.

  • Earle, M. D., 1996: Nondirectional and directional wave data analysis procedures. NDBC Tech. Doc. 96-01, 37 pp. [Available from NDBC, Stennis Space Center, MS 39529.].

  • Ewans, K. C., 1998: Observations of the directional spectrum of fetch-limited waves. J. Phys. Oceanogr.,28, 495–512.

  • Hasselmann, D. E., M. Dunckel, and J. A. Ewing, 1980: Directional wave spectra observed during JONSWAP 1973. J. Phys. Oceanogr.,10, 1264–1280.

  • Hasselmann, K., 1974: On the spectral dissipation of ocean waves due to whitecapping. Bound.-Layer Meteor.,6, 107–127.

  • Holthuijsen, L. H., 1983: Observations of the directional distribution of ocean-wave energy in fetch-limited conditions. J. Phys. Oceanogr.,13, 191–207.

  • Hwang, P. A., E. J. Walsh, W. B. Krabill, R. N. Swift, S. S. Manizade, J. F. Scott, and M. D. Earle, 1998: Airborne remote sensing applications to coastal wave research. J. Geophys. Res.,103, 18 791–18 800.

  • ——, D. W. Wang, E. J. Walsh, W. B. Krabill, and R. N. Swift, 2000:Airborne measurements of the wavenumber spectra of ocean surface waves. Part I. Spectral slope and dimensionless spectral coefficient. J. Phys. Oceanogr.,30, 2753–2767.

  • Jackson, F. C., W. T. Walton, and C. Y. Peng, 1985: A comparison of in situ and airborne radar observations of ocean wave directionality. J. Geophys. Res.,90, 1005–1018.

  • Komen, G. J., S. Hasselmann, and K. Hasselmann, 1984: On the existence of a fully developed wind-sea spectrum. J. Phys. Oceanogr.,14, 1271–1285.

  • Krabill, W. B., R. H. Thomas, K. Jezek, C. Kuivinen, and S. Manizade, 1995a: Greenland ice sheet thickness changes measured by laser altimetry. Geophys. Res. Lett.,22, 2341–2344.

  • ——, ——, C. F. Martin, R. N. Swift, and E. B. Frederick, 1995b: Accuracy of airborne laser altimetry over the Greenland ice sheet. Int. J. Remote Sens.,16, 1211–1222.

  • Longuet-Higgins, M. S., D. E. Cartwright, and N. D. Smith, 1963: Observations of the directional spectrum of sea waves using the motions of a floating buoy. Ocean Wave Spectra, Prentice Hall, 111–136.

  • Lygre, A., and H. E. Krogstad, 1986: Maximum entropy estimation of the directional distribution in ocean wave spectra. J. Phys. Oceanogr.,16, 2052–2060.

  • Mitsuyasu, H., and Coauthors, 1975: Observation of the directional wave spectra of ocean waves using a cloverleaf buoy. J. Phys. Oceanogr.,5, 750–760.

  • Oltman-Shay, J., and R. T. Guza, 1984: A data-adaptive ocean wave directional spectrum estimator for pitch–roll type measurements. J. Phys. Oceanogr.,14, 1800–1810.

  • Phillips, O. M., 1958: On some properties of the spectrum of wind-generated ocean waves. J. Mar. Res.,16, 231–240.

  • ——, 1985: Spectral and statistical properties of the equilibrium range in wind-generated gravity waves. J. Fluid Mech.,156, 505–531.

  • Wyatt, L. R., 1995: The effect of fetch on the directional spectrum of Celtic Sea storm waves. J. Phys. Oceanogr.,25, 1550–1559.

  • Young, I. R., 1994: On the measurement of directional wave spectra. Appl. Ocean Res.,16, 283–294.

  • ——, and G. Ph. Van Vledder, 1993: A review of the central role of nonlinear interactions in wind-wave evolution. Philos. Trans. Roy. Soc. London,A342, 505–524.

  • ——, L. A. Verhagen, and M. L. Banner, 1995: A note on the bimodal directional spreading of fetch-limited wind waves. J. Geophys. Res.,100, 773–778.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 343 74 2
PDF Downloads 123 60 1

Airborne Measurements of the Wavenumber Spectra of Ocean Surface Waves. Part II: Directional Distribution

View More View Less
  • 1 Oceanography Division, Naval Research Laboratory, Stennis Space Center, Mississippi
  • | 2 NASA/GFSC/WFF, Wallops Island, Virginia
  • | 3 EG&G, WFF, Wallops Island, Virginia
Restricted access

Abstract

An airborne scanning lidar system acquires three-dimensional (3D) spatial topography of ocean surface waves. From the spatial data, wavenumber spectra are computed directly. The spectral properties in terms of the spectral slope and dimensionless spectral coefficient have been verified to be in very good agreement with existing data. One of the unique features of the 3D spatial data is its exceptional directional resolution. Directional properties such as the wavenumber dependence of the directional spreading function and the evolution of bimodal development are investigated with these high-resolution, phase-resolving spatial measurements. Equations for the spreading parameters, the lobe angle, and the lobe ratio are established from the airborne scanning lidar datasets. Fourier decomposition of the measured directional distribution is presented. The directional parameters can be represented by a small number (4) of the Fourier components. The measured directional distributions are compared with numerical experiments of nonlinear wave simulations to explore the functional form of the dissipation source term.

Additional affiliation: NOAA/ETL, Boulder, Colorado.

Corresponding author address: Dr. Paul A. Hwang, Oceanography Division, Naval Research Laboratory, Stennis Space Center, MS 39529-5004.

Email: paul.hwang@nrlssc.navy.mil

Abstract

An airborne scanning lidar system acquires three-dimensional (3D) spatial topography of ocean surface waves. From the spatial data, wavenumber spectra are computed directly. The spectral properties in terms of the spectral slope and dimensionless spectral coefficient have been verified to be in very good agreement with existing data. One of the unique features of the 3D spatial data is its exceptional directional resolution. Directional properties such as the wavenumber dependence of the directional spreading function and the evolution of bimodal development are investigated with these high-resolution, phase-resolving spatial measurements. Equations for the spreading parameters, the lobe angle, and the lobe ratio are established from the airborne scanning lidar datasets. Fourier decomposition of the measured directional distribution is presented. The directional parameters can be represented by a small number (4) of the Fourier components. The measured directional distributions are compared with numerical experiments of nonlinear wave simulations to explore the functional form of the dissipation source term.

Additional affiliation: NOAA/ETL, Boulder, Colorado.

Corresponding author address: Dr. Paul A. Hwang, Oceanography Division, Naval Research Laboratory, Stennis Space Center, MS 39529-5004.

Email: paul.hwang@nrlssc.navy.mil

Save