W A VE DYNAMICS AND RADIO PROBING OF THE ÜCEAN SURFACE W A VE DYNAMICS AND RADIO PROBING OF THE OCEAN SURFACE Edited by O. M. PHILLIPS The lohns Hopkins University Baltimore, Maryland and KLAUS HASSELMANN Max Planck Institute for Meteorology Hamburg, Federal Republic of Germany PLENUM PRESS • NEW YORK AND LONDON Library of Congress Cataloging in Publication Data Wave dynamics and radio probing of the ocean surface. "Proceedings of a symposium ... held May 13-20, 1981, in Miami, Florida, spon- sored by the Inter-Union Commission on Radio Meteorology"-T.p. verso. Bibliography: p. Includes index. 1. Ocean waves-Congresses. 2. Oceanography-Remote sensing-Congresses. 3. Microwave devices-Congresses. I. Phillips, O. M. (Owen M.), 1930- .11. HasseI- mann, Klaus, 1931- .111. Inter-Union Commission on Radio Meteorology. GC206.W38 1986 551.47'022 86-8106 ISBN 978-1-4684-8982-8 ISBN 978-1-4684-8980-4 (eBook) DOI 10.1007/978-1-4684-8980-4 Proceedings of a symposium on Wave Dynamics and Radio Probing of the Ocean Surface, held May 13-20, 1981, in Miami, Florida, sponsored by the Inter-Union Commission on Radio Meteorology © 1986 Plenum Press, New York Softcover reprint of the hardcover 1s t edition 1986 A Division of Plenum Publishing Corporation 233 Spring Street, New York, N.Y. 10013 All rights reserved No part of this book may be reproduced, stored in aretrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE In 1960, Dr. George Deacon ofthe National Institute ofOceanography in England organized a meeting in Easton, Maryland that summarized the state of our understanding at that time of ocean wave statistics and dynamics. It was a pivotal occasion: spectral techniques for wave measurement were beginning to be used, wave-wave interactions hadjust been discovered, and simple models for the growth of waves by wind were being developed. The meeting laid the foundation for much work that was to follow, but one could hardly have imagined the extent to which new techniques of measurement, particularly by remote sensing, new methods of calculation and computation, and new theoretical and laboratory results would, in the following twenty years, build on this base. When Gaspar Valenzuela of the V.S. Naval Research Laboratory perceived that the time was right for a second such meeting, it was natural that Sir George Deacon would be invited to serve as honorary chairman for the meeting, and the entire waves community was delighted at his acceptance. The present volume contains reviewed and edited papers given at this second meeting, held this time in Miami, Florida, May 13-20, 1981, with the generous support of the Office of Naval Research, the National Aeronautics and Space Administration, and the National Oceanic and Atmospheric Administration. The range of contributions illustrates clearly the much more powerful measurement techniques that have become available since 1960 and the firmer and more extensive observational base that has been built up as a result. They show the greatly enhanced level of dynamical sophistication with which we view ocean wave characteristics and structure. Many important questions remain but it is to be hoped that the advances described in this book will serve as a timely summary of the state of the art that will be of interest to oceanographers, ocean engineers, and meteorologists and will, at the same time, reset the stage for future directions of research. Klaus Hasselmann O. M. Phillips v CONTENTS Keynote Addresses Sir George Deacon, Honorary Chairman . . . . . . Dr. William Rainey, NASA . . . . . . . . . . . 2 Mr. Herbert Rabin, Deputy Assistant Secretary of the Navy 3 I. Oeean Wave Speetra 1. The Equilibrium Ranges in Wind-Wave Spectra: Physical Arguments and Experi- mental Evidence for and against Their Existence. . . . . . . . . . . 9 S. A. Kitaigorodskii 2. Nonlinear Energy Transfer between Random Gravity Waves: Some Computational Results and Their Interpretation. . . . . . . . . . . . . . . .. 41 Akira M asuda 3. The Interaction between Long and Short Wind-Generated Waves . 59 M. T. Landahl, J. A. Smith, and S. E. Widnall 4. Energy Distribution of Waves above 1 Hz on Long Wind Waves . 75 Karl Richter and Wolfg ang Rosenthal 5. The Effects of Surfactant on Certain Air-Sea Interaction Phenomena . 95 H. Mitsuyasu and T. Honda 6. Experimental Study of Elementary Processes in Wind-Waves Using Wind over Regular Waves. . . . . . . . . . . . . . . . . . . . . .. 117 Yoshiaki Toba, Mitsuhiko Hatori, Yutaka Imai, and Masayuki Tokuda 7. An Experimental Study of the Statistical Properties of Wind-Generated Gravity Waves. . . . . . . . . . . . . . . . . . . . . . . . .. 129 Norden E. Huang, Steven R. Long, and Larry F. Bliven 8. On Finite-Depth Wind-Wave Generation and Dissipation. 145 C. E. Knowles 9. The Equilibrium Range for Waves in Water of Finite Depth . 161 Dinorah C. Esteva 11. Wave Propagation 10. The 1978 Ocean Wave Dynamics Experiment: Optical and in Situ Measurement of the Phase Velocity of Wind Waves. . . . . . . . . . . . . . .. 165 G. B. Irani, B. L. Gotwols, and A. W. Bjerkaas vii viii CONTENTS 11. Transformation ofStatistical Properties ofShallow-Water Waves . . . .. 181 B. Le Mehaute, c. c. Lu, and E. W. Ulmer 12. Aspects of the Velocity Field and Dispersion Relation in Surface Wind Waves. 193 V. V. Yefimov and B. A. Nelepo III. Wave Instabilities and Breaking 13. Advances in Breaking-Wave Dynamies . . . . . . . . . . . . .. 209 M. S. Longuet-Higgins 14. Experimental Studies of Strong Nonlinear Interactions of Deep-Water Gravity Waves. . . . . . . . . . . . . . . . . . . . . . . . .. 231 Ming-Yang Su and Albert W. Green 15. The Instability and Breaking of a Deep-Water Wave Train 255 W. K. Melville 16. Measurements of Breaking Waves: Implieations for Wind-Stress and Wave Generation . . . . . . . . . . 257 M. S. Longuet-Higgins and N. D. Smith 17. Statistical Charaeteristies of Breaking Waves 265 Yeli Yuan, C. C. Tung, and Norden E. Huang 18. On Mierowave Scattering by Breaking Waves 273 Lewis Wetzel 19. Observation of Breaking Oeean Waves with Coherent Mierowave Radar 285 W. C. Keller, W. J. Plant, and G. R. Valenzuela 20. An Estimate of the Influenee of Breaking Waves on the Dynamics of the Upper Oeean . . . . . . . . . . . . . . . . . . . . . . . . .. 295 Norden E. Huang 21. Stability of Nonlinear Capillary Waves 315 S. J. Hogan IV. Air Flow over Waves 22. A Comparison of the Wave-Indueed Momentum Flux to Breaking and Nonbreaking Waves. . . . . . . . . . . . . .. .... 321 M. L. Banner 23. Observations and Measurements of Air Flow over Water Waves 335 M. A. Weissman 24. Measurements of Wave-Indueed Pressure over Surfaee Gravity Waves 353 D. Hasselmann, J. Bösenberg, M. Dunckel, K. Richter, M. Grünewald, and H. Carlson V. Methods of Remote Sensing 25. The SAR Image of Short Gravity Waves on a Long Gravity Wave. 371 Robert O. H arger 26. The Response of Synthetie Aperture Radar to Oeean Surfaee Waves 393 Klaus Hasselmann and Werner Alpers CONTENTS ix 27. On the Ability of Synthetie Aperture Radar to Measure Oeean Waves 403 J. F. Vesecky, R. H. Stewart, R. A. Shuchman, H. M. Assal, E. S. Kasischke, and J. D. Lyden 28. Limitations of the SEASAT SAR in High Sea States . . . . . . . . .. 423 F. M. Monaldo and R. C. Beal 29. Mierowave Seattering from Short Gravity Waves: Deterministie, Coherent, Dual Polarized Study of the Relationship between Baekseatter and Water Wave Properties. . . . . . . . . . . . . . . . . . . . . . . .. 443 Daniel S. W. K woh and Bruce M. Lake 30. Remote Sensing of Direetional Wave Speetra Using the Surfaee Contour Radar 449 E. J. Walsh, D. W. Hancock, III, D. E. Hines, and J. E. Kenney 31. The Visibility of rms Slope Variations on the Sea Surface . 465 R. D. Chapman VI. Sea Surface Measurements 32. Southern Oeean Waves and Winds Derived from SEASAT Altimeter Measurements 479 Nelly M. Mognard, William J. Campbell, Robert E. Cheney, James G. Marsh, and Duncan V Ross 33. Marineland Aireraft Observations of L-Band Radar Baekseatter Dependenee upon Wind Direetion. . . . . . . . . . . . . . . . . . . . . .. 491 T. W. Thompson, D. E. Weissman, and W. T. Liu 34. Mierowave Measurements over the North Sea. . . . . . . . . . .. 505 G. P. De Loor, P. Hoogeboom, R. Spanhoff, and J. Bruinsma 35. Some Skywave Radar Measurements of Wind Veetors and Wave Speetra: Com- parison with Conventional Data for'JASIN 1978. . . . . . . . . .. 517 P. E. Dexter and S. Theodoridis 36. Study of the Modulation by Correlation in the Time and Frequeney Domains of Wave Height and Mierowave Signal: Preliminary Results. . . . . . .. 529 Danielle de Staerke and Andre Fontanel 37. HF Radar Measurements of Wave Speetral Development . 541 Dennis B. Trizna 38. Passive Mierowave Probing of Roughened Sea. 555 A. M. Shutko VII. Wave Modeling 39. Inverse Modeling in Oeean Wave Studies 571 Robert Bryan Long 40. Comparisons of Hurrieane Fieo Winds and Waves from Numerieal Models with Observations from SEASAT-A . . . . . . . . . . . . . . . .. 595 Duncan Ross, Linda M. Lawson, and William McLeish 41. Modeling Wind-Driven Sea in Shallow Water 615 J. W. Sanders and J. Bruinsma x CONTENTS 42. An Evaluation of Operational Wave Forecasts on Shallow Water. . . .. 639 E. Bouws, G. J. Komen, R. A. van Moerkerken, H. H. Peeck, and M.J.M. Saraber 43. Anomalous Dispersion in Numerical Models of Wave Spectra . . . . .. 661 William Carlisle Thacker 44. Some Problems in the Development of the National Coastal Waves Pro gram . 671 L. Baer, D. Esteva, L. Huff, W. lseley. R. Ribe. and M. Earle 45. Models for the Hurricane Wave Field . 677 D. Lee Harris Participants 683 Index. . . 689 KEYNOTE ADDRESSES SIR GEORGE DEACON, HONORARY CHAIRMAN Twenty years ago, Walter Munk welcomed the wave conference at Easton as a great concentration of talent marking the change of wave studies from an art to a science. Since then we have seen a great awakening by industry and governments to the commercial and safety value ofreliable information. They sometimes complain about apparent deficiencies, but considering the late start and primary dependence on individual enthusiasms, it is remarkable how much progress has been made. It is rather surprising how little attention was paid to waves in the early days. M. F. Maury does not say much about them, nor did they receive much attention in the Challenger Reports. The voluminous Sailing Directions, much used by seamen in the late 19th and early 20th centuries, are content with thorough reporting of wind patterns and do not saymuch about waves. Krümmel(1911), Thorade(1931), and Cornish(1934) are great sources of information, but the real growth of the subject, and the essential cooperation of theory and observation, did not begin ti11 its problems became urgent during the Second World War. The 1961 meeting highlighted key problems and a few ofthem, like the need to record air pressures elose to the surface with sufficient accuracy for comparison with wave profiles, and the need for more measurements of directional spectra and the attenuation of swe11 over long distances, remain hard-core problems. But good progress has been made in many others, in improvement of measuring techniques, in understanding the nonlinear processes involved in wave interaction and breaking of waves, and in collecting long time-series of observations. It is encouraging to see how long-term studies of the physical processes, essential for ultimate satisfaction, are surviving the increasing demands for immediate figures. The scatter between individual methods offorecasting and hindcasting is much less than it was, though there are more uncertainties in the methods of predicting extreme conditions. One of them is an apparent change, usually a decrease in height, as waves pass from the deep ocean to coastal waters. There are still many problems requiring specialists and active cooperation between theoretical physicists, instrumentalists, and engineers. The rapid development of radio measuring techniques ca11s for another discussion of all aspects of the subject. Every now and then in oceanography, and, I suppose, in other applied sciences, a new method of approach promises final solutions to many of our problems, and only afterwards do we learn some details that limit its usefulness in some directions and make it fu11y efIective in others. In such aperiod of active growth we have to be as elear as possible about what measurements are most needed and how they can best be made. I suspect that my invitation to Miami is large!y a reco11ection of the happy, friendly conditions which he!ped to bring success to the meeting 20 years ago. The organizers and sponsors of this new opportunity have set up equa11y promising conditions, in which, I am sure, much good work will be done. SIR GEORGE DEACON • Institute of Oceanographic Sciences, Wormley, England. 2 KEYNOTE ADDRESSES WILLIAM RAINEY On behalf ofTony Calio, the Associate Administrator for NASA's Office ofSpace and Terrestrial Applications, I am delighted to address this symposium, and I wish to thank the Inter-Union Commission on Radio Meteorology, the American Meteorological Society, NOAA, and ONR for their joint sponsorship. In preparing for this meeting, I went back to two books to familiarize myself with some past history in the field of ocean waves. The first article I looked at was on "Wave Generation by the Wind" by Fritz UrseIl, in the G. I. Taylor birthday book. Twenty-five years ago, he wrote: Wind blowing over a water surface generates waves in the water by physical processes which cannot be regarded as known. ... What part is played by the air boundary layer and the air turbulence level? At what distance (if any) do the wave motions at different points cease to interact significantly? What part (if any) is played by minute roughnesses on the sea surface? These comments and questions are still applicable today, 25 years later. The other book to which I turned was Ocean Wave Spectra, which was the product of a symposium, much like this one, held in Easton, Maryland, 20 years ago this month, to discuss the measurement of ocean wave spectra. Sir George Deacon, the honorary chairman ofthis present symposium, reviewed the status ofwave research at that symposium. Let me quote briefly from his review: The question ofhow waves are generated must be regarded 'lS one of overriding importance. ... It seems superfluous to insist that the greatest need is still for closer integration of theory and experiment. Observations of one sort and another are urgently required for a variety of purposes, but a lot of elTort will be saved when we have a better understanding of the physical processes involved. A systematic approach is not only more satisfying, it is forced on us by the scope and difficulty of the problems that have still to be solved. We must not be afraid of venturing outside the circle of past experience .... These comments also are still applicable today, 20 years later. Much progress has been made in the past two decades, of course, although the specific topics to which these generalized comments apply now are certainly different. For example, of the 30 papers presented at Easton, only one was directed toward remote sensing-a radar paper by Frank McDonaid. Of the 75 papers at this symposium, 26 are on remote sensing. The goal of most of these papers, however, is a common one: the understanding and measurement of ocean wave spectra. One of the goals of NASA's Oceanic Processes Branch is to provide the capability for measuring and making available to users (Navy, NOAA, commercial, and academic research) the two-dimensional ocean wave height spectrum. Let me give you a brief summary of some of our accomplishments in this field, and then tell you of our future plans. NASA workers and NASA-supported researchers have participated in numerous neid experiments involving the remote sensing ofwaves, such as Marineland, West Coast Experiment, Joint Air-Sea Interaction Study (JASIN), Marine Remote Sensing Experiment (MARSEN), Gulf of Alaska Surface Experiment (GOASEX), Storm Response Experiment (STREX), and Atlantic Remote Sensing Land Ocean Experiment (ARSLOE). The SEASAT mission provided two instruments for wave measurements: the synthetic aperture radar (SAR) and the altimeter. Other remote sensing instruments developed and flown by NASA investigators are: 1. Dual-frequency scatterometer for measuring the 2-D spectrum from aircraft 2. Short-pulse radar, also for measuring the 2-D spectrum from aircraft 3. Surface contour radar, which measures the 2-D wave height field (and thence spectra through Fourier transformation) 4. Airborne oceanic lidar (AOL), which can determine a 1-D spectrum 5. SAR, both SEASAT and aircraft. The SAR can be used to determine wave length and direction, and recently some quantitative wave height information has been extracted.