Abstract
Radar measurements of wave height are compared with independent measurements made during the JONSWAP-2 experiment by Waverider and pitch-roll buoys, a shipborne wave recorder and a laser profilometer. The radar data were recorded by a Naval Research Laboratory (NRL) nanosecond-pulse X-band radar altimeter flown in a NASA C-54 aircraft at 3-km altitude under various wind and sea conditions. Averages of 800 pulses of the pulse-limited altimeter data were used to calculate maximum-likelihood estimates of significant wave height (SWH) and skewness of the sea-surface height distribution. The mean values of the radar-estimated SWH were in good agreement with the other measurements. The standard deviation of the values of the radar measurements was typically 10% of the average wave height. A two-dimensional computer simulation of the sea surface indicates that the major portion of the observed standard deviation is attributable to the relatively small sea-surface area illuminated by the radar (125 m × 900 m) rather than to instrumental error. Increasing the number of pulses averaged reduced the variance in the estimates without changing the means. The mean value of the skewness parameter was generally near zero but the standard deviation was typically 0.25. The estimate of SWH did not change when the skewness parameter was constrained to zero.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Barrick, D. E.: 1972, ‘Remote Sensing of the Sea State by Radar’, in (V. E. Derr, ed.)Remote Sensing of the Troposphere U. S. Government Printing Office, Washington, D.C. 10402, 12–34, 12–41.
Berger, T.: 1972, ‘Satellite Altimetry Using Ocean Backscatter’,IEEE Trans. Antennas Propagation AP-20, 295–309.
Brooks, L. W. and Dooley, R. P.: 1975, ‘Technical Guidance and Analytic Services in Support of SEASAT-A’, NASA Contractor Report CR-141399, NASA Wallops Flight Center, Wallops Island, VA 23337, N75-20803, pp. I-3-11 to I-3-33.
Dooley, R. P., Brooks, L. W., and Khowry, E. N.: 1976, ‘Optimization of Satellite Altimeter and Wave Hiehgt Measurement’, Final Report under NASA Contract NAS6-2601, NASA Wallops Flight Center, Wallops Island, VA 23337, 85.
Hasselmann, K., Barnett, T. P., Bouws, E., Carlson, H., Cartwright, D. E., Enke, K., Ewing, J. A., Gienapp, H., Hasselmann, D. E., Kruseman, P., Meerburg, A., Müller, P., Olbers, D. J., Richter, K., Sell, W., Walden, H.: 1973, ‘Measurements of Wind-Wave Growth and Swell Decay During the Joint North Sea Wave Project (JONSWAP)’,Deut. Hydrogr. Z., Suppl. A,8, No. 12, 95.
Hoffman, D. and Karst, O. J.: 1975, ‘The Theory of the Rayleigh Distribution and Some of its Applications’,J. Ship Res.:19, 172–191.
Longuet-Higgins, M. S.: 1952, ‘On the Statistical Distribution of the Heights of Sea Waves’,J. Marine Res. XI, 245–266.
Miller, L. S. and Hayne, G. S.: 1972, ‘Characteristics of Ocean-Reflected Short Radar Pulses with Application to Altimetry and Surface Roughness Determination’,Sea Surface Topography from Space, vol. 1,NOAA Tech. Rep. ERL 228-AOML 7, U.S. Government Printing Office, Washington, D.C. 20402, N73-15381, 12-1 to 12-32.
Neumann, G. and Pierson, W. J.: 1966,Principles of Physical Oceanography, Prentice-Hall, Englewood Cliffs, NJ, 351.
Rice, S. O.: 1944, 1945, ‘The Mathematical Analysis of Random Noise’,Bell System Tech. J. 23, 282–322;24, 46–156.
Walsh, E. J.: 1974, ‘Analysis of Experimental NRL Radar Altimeter Data’,Radio Sci. 9, 711–722.
Walsh, E. J.: 1977, ‘Problems Inherent in Using Aircraft for Radio Oceanography Studies’,IEEE Trans. Antennas Propagat.AP-23, No. 1, 145–149.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Walsh, E.J., Uliana, E.A. & Yaplee, B.S. Ocean wave heights measured by a high resolution pulse-limited radar altimeter. Boundary-Layer Meteorol 13, 263–276 (1978). https://doi.org/10.1007/BF00913877
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00913877