A plausible hypothesis on the velocity distribution under a free surface is that it obeys the ``law of the wall,'' best remembered for the logarithmic velocity profile with minor variations due to waves. Gabe has summarized some evidence before supporting this idea (Figure 2). Gabe found that one of its weaknesses is that it ignores Stokes drift, the residual particle motion of waves. The main argument against the validity of the law of the wall is, however, that waves may well distribute their momentum over a substantial portion of the mixed layer, bypassing the near surface shear flow: some authors speak of the ``wave-mixed layer.'' Is this really the case?
The mixed layer gains momentum from the waves, as the waves lose it. Deepwater waves lose momentum by two mechanisms: viscous drag on orbital motions and wave breaking, a process akin to boundary layer separation in steep waves sometimes made visible by the the foam and bubbles of a spilling breaker. Classical hydrodynamic theory shows that the effects of viscous drag are confined to a thin wave-boundary layer at the surface, and just underneath this layer, the waves exert a mean viscous stress (by maintaining mean shear in addition to the gradient of Stokes drift). Thus, loss of wave momentum due to viscosity, including eddy viscosity action on long waves, appears as Reynolds flux already very close to the surface.
That a similar conclusion holds for wave momentum loss in breakers has only become clear recently, from detailed studies of the flow field in breaking waves. Steady breakers can be produced in the laboratory, on a steep standing wave behind a submerged obstacle, simulating the flow pattern of a spilling breaker in a wave-following frame of reference. A prominent feature of the flow in a breaker is fluid overtaking the wave at the crest. In a wave-following frame, this translates into two stagnation points on the surface where the fluid is at rest relative to the wave and a closed circulation cell within a ``roller'' sitting on top of the wave, separated from the regular wave motion. The weight of the roller presses down on the wave in such a way as to extract momentum from the wave, transferring it to a ``wake'' (near surface shear flow) by Reynolds stress. Observations show high Reynolds stress a few centimeters below the surface. The ``wave to wake momentum conversion'' (Figure 3) is thus analogous to viscous drag on waves in that it occurs close to the surface.
Scaling the argument up to breaking long waves impairs the analogy somewhat because ``close'' to the surface on the scale of long waves is not close enough for the logarithmic profile to survive. The question then becomes, for what fraction of momentum transfer, the long breaking waves are responsible. The evidence is not entirely convincing, but it points to something of the order of 6 of total momentum transfer, the fraction known to be absorbed by the increasing momentum of growing waves. Even this much is difficult to explain, given that long waves move almost as fast as the wind. The hydrodynamic theory of wave generation by wind due to Miles attributes wave growth to momentum transfer from the ``critical'' layer in the air flow above the surface, moving as fast as the wave, at a rate proportional to the second derivative of the air velocity at the critical layer. Because this second derivative has high values only at very short distances above the surface, where the air flow is slow, the Miles mechanism is most effective in momentum transfer to short waves, say those with a wavelength of the order of 10 cm. Detailed studies of short waves in the laboratory at Tohoku University in Sendai, Japan have indeed established the prominent role of such waves in air-sea momentum transfer.
It is thus reasonable to conclude that the different streams of momentum transfer almost completely unite at a few centimeters below the surface. How this affects the slip velocity requires exploration of the Stokes drift-shear flow interaction, and this is what Gabe is struggling with now.
Legends for illustrations:
Fig.1 The different streams of momentum flux crossing the sea surface
Fig.2 Logarithmic velocity distribution underneath the sea surface observed in various locations
Fig.3 Roller and its wake in a wave-following frame of reference
Gabe was a key figure in the development of physical oceanography at ODU and the establishment of the Commonwealth Center for Coastal Physical Oceanography. When a group is young and growing, it needs the experience and credibility of someone like Gabe. He provided that and more.
During his eight-year stay here, Gabe published over 20 papers and book chapters. Just a sampling of the titles shows his eclectic interests:
``Ocean currents over the continental shelf,''
``Momentum flux in breaking waves,''
``Retroflection and leakage in the North Brazil Current,''
``Wavelets and air-sea transfer,'' and
``Vortex pair model of Langmuir Circulation.''
I won't even list Gabe's research funding except to say that he received over 1.5M during his stay at ODU.
While Gabe wasn't much for following institutional issues, he did serve on a university committee to review the use of research overhead funds. Never shy about his thoughts, Gabe was quoted saying, ``University attitude towards allocation and spending of research overhead was larcinous.'' Fortunately, the present administration has significantly changed the way overhead is distributed.
I think what most of us learned from Gabe was to stay focused. As you go through your career, from young researcher and teacher, to the stage where administration tempts you, and finally to the stage where you want to finish research started long ago and teach those last graduate students what the years have told you they need to know -- stay focused.
I speak for all those at ODU when I say we will miss Gabe, but we look forward to seeing what Gabe focuses on next.
Larry P. Atkinson
Director, Center for Coastal Physical Oceanography
The real world intruded when Russian troops started laying siege to Budapest. We escaped on one of the last trains out before they encircled the city. The spring of 1945 was beautiful. With two other young fellows, we criss-crossed the Bavarian and Austrian Alps, hitchhiking on army trucks and banging on the drivers' cabins when airplanes came into sight, so that the drivers could jam on their brakes and duck in a roadside ditch. Overnight accommodation was not luxurious. I remember sleeping on a narrow table, belted to another fellow back to back, so we would not fall off. When the war ended, my companions and I were in Innsbruck with one pair of pants between the three of us. When one of us went out, two had to stay home.
The Technische Hochschule in Munich reopened in early 1946, and I enrolled in my second year in mechanical engineering. Student years are always great. Jitterbug was popular, but food supplies were erratic. Once I lived on cheese for a week. I also went ``hamstern'' in the Swabian countryside for apples (go house to house and offer to buy) to stock up for the winter.
We emigrated to Australia in 1949, sailing from Naples to Sydney. On the Red Sea, the dining room temperature was 138 degrees. We celebrated reaching the Indian Ocean rather too well--that was the only time I ever got seasick. After a few interesting jobs in the migrant camp (PA announcer, interpreter for the camp director, kitchen supervisor) and engineering jobs outside, I got involved in air pollution research. One memorable duty was to sample flue gases from a chimney platform 150 feet above rooftop (and I always hated heights). One of my assistants just sat with his back against the stack, petrified. In compensation, though rather later, the University of New South Wales gave me a Ph.D. for a thesis entitled ``Dispersal of dust from industrial stacks.'' My first paper, on the same topic, appeared in the Australian Journal of Physics in 1955, and it made me walk on air.
Soon after taking a post at the University of Windsor, Ontario, a colleague from Toronto visited me (Ted Munn, much later, until recently, the editor of Boundary Layer Meteorology). Ted told me about a great field project on the shores of Lake Huron where the government was about to build a large nuclear power station. Ted was carrying out atmospheric dispersal studies at the site. Upon my envious congratulations, he suggested that I do similar studies of effluent dispersal in the Lake, so I started my association with the University of Toronto on limnological research and later to evolve into work on coastal physical oceanography.
The 1960s were my ``Sturm und Drang'' period. In 1963, I became department chairman in mechanical engineering at the University of Waterloo, ran a research station on Lake Huron for the University of Toronto, and acquired seven Ph.D. students. Waterloo operates year-round, and one of the three semesters is ``off'' for faculty. I spent these at the Travelers Research Center in Hartford, CT, on air pollution work, or at the University of Wisconsin, Madison, on lake dynamics studies. The Canadian Meteorological Society awarded me their President's Prize in 1970; the American Meteorological Society their Editor's Award in 1975; the International Association for Great Lakes Research their Chandler-Misener Award in 1977; and the Bedford Institute of Oceanography's A. G. Huntsman Award in 1991.
All was not rosy, however. My first marriage blew up in 1965, and it was followed by a distressing period and a bitter divorce. To my great good fortune, this did not last long. A then recently widowed lady neighbor just happened to be the woman heaven intended for me. Joyce has been my love and inspiration for almost thirty years now. She soon helped me over my troubles, a task not made easier by frequent changes of venue. When we moved to Madison for an ``off'' semester in 1966, I just happened to be in Japan attending a conference (together with A. D. Kirwan, Jr., as a photograph testifies). Officials at the airport at Tokyo made difficulties about returning to the U.S. with my H1 visa; I almost got stuck there with 30 in my pocket. The Toyko officials relented in the end and kindly rebooked me to Toronto. When I got to Madison in the middle of the night, I had to call a colleague to find out where we lived.
Joyce also came with three lovely daughters, Pat, Connie, and Susan, with whom we now form a harmonious family, including sons-in-law, my son Andrew, his lady, and grandchildren. On top of this, one role Joyce has always enjoyed was to play surrogate mother to graduate students. For my seven students in Waterloo, we gave a ``seven son's party.'' Each was awarded a separate diploma. To name a few, one became Doctor of Safety, remembering that he just missed blowing up the lab with his oil smoke windtunnel studies. Another was honored for his ``brilliant blackboard technique,'' conducting his thesis defense with liberal blackboard use in complete darkness.
The last two ``off'' semesters (these could be saved up and pushed together) I spent at Woods Hole as a guest investigator in 1972-73. We made wonderful friends there and were fortunate enough to be able to return on a permanent basis after a final semester in Waterloo. With a retired English professor couple, we debated sundry subjects holy and profane. In our gourmet club, we explored dishes of the world. I would not recommend Danish beer soup (tastes like wet bread), ginseng root (effective emetic), or retsina wine (wine and turpentine). We had a vizsla, ``Scrooge'' (Hungarian hunting dog, like my grandfather had, who could easily have got a Ph.D. at one of the lesser institutions); a horse for Susan in her teen years, ``Cricket;'' and built a dance hall in the basement for ourselves, keen ballroom dancers.
A nice interlude in our life was Pasadena in 1982, when CalTech honored me with a Sherman Fairchild Distinguished Fellowship. California poppies, date palms, and Palm Spring weekends were wonderful. In Norman Brooks' Environmental Engineering Science Group, where my office was, I learned such tidbits as that the pH of dew in the local park was 2.0. We were also delighted to find a ballroom dance studio in Los Angeles with the most accomplished dance teachers anywhere, people we later saw on TV. The lessons we took there remain among our fondest memories.
So far I have not said anything about our cottage, a thing of beauty on the shores of Lake Huron, which is indeed a joy for ever. We built it in 1966, just south of the site of the field studies I mentioned. This is a family seat to which we have returned every single summer for family gatherings, barbecues, and uncrowded golf courses. I have a second-story office over the boathouse, which overlooks the lake.
In 1987, William Dunstan, then chairman of the Department of Oceanography at Old Dominion University, was kind enough to hire me for a Slover chair. Joyce and I bought a house in Virginia Beach, VA and promptly decided we did not like the house's looks, so we had it remodeled while living there. This was as messy a project as Joyce ever had the pleasure of enduring with me. We have one photo of the house wrapped in plastic to keep out the rain, which came copiously that winter. Landscaping the grounds, one of my enduring hobbies, was great fun.
The Cape has now claimed us again. We built our dream house in Sandwich and will be leaving you good friends presently. I am happy to have taken part in the effort to launch CCPO, and I have very much enjoyed having a group of graduate students again, decades after the Waterloo years. Thanks for the memory.
As a result of this project, David became a full-time student in the fall of 1991 in the Department of Oceanography with Dr. Klinck as his primary advisor. David's current research interests are the study of the water mass distribution and regional circulation west of the Antarctic Peninsula. This research is part of the Long-Term Ecological Research (LTER) program and includes the synthesis of multi-seasonal hydrographic data along with the development of a numerical circulation model. The field portion of the project offered David an opportunity to spend two months in the Antarctic. David is adapting the general circulation Princeton Ocean Model (POM) for use in the region. The numerical model will then be used to examine fundamental circulation and water mass interactions. This circulation has implications towards nutrient distribution and the biology for the shelf. After graduation, David intends to remain in research.
A. D. KIRWAN, JR., "Quantiative Utilization of Lagrangian Data in Numerical Models," $35,285, ONR.
G. H. WHELESS, ``Modeling Inlet Processes and Alongshore Transport: Relationships to Biological Recruitment,'' $85,116, VGMSC.
G. H. WHELESS and J. M. KLINCK, ``The Role of External Forcing and Tidal Effects on the Behavior of a Buoyant Estuarine Plume,'' $55,000, NSF.
Ph.D.: G. V. R. K. VITTAL, dissertation title, "Thermocline Circulation Driven at Surface Outcrops of Isopycnal Surfaces," May 1995, Advisor: G. T. Csanady.
L. A. CODISPOTI, ``Platform Needs vs. Research Priorities for Chemical Oceanographic Studies of the Arctic,'' invited talk for the Committee on the Arctic Research Vessel, National Research Council, NRC Beckman Center, Irvine, CA, March 28, 1995.
M. M. DEKSHENIEKS, E. E. Hofmann, J. M. Klinck, and E. N. Powell, Rutgers University, ``Spatial Patterns of Oyster Distribution: A Modeling Study,'' Marine Benthic Ecology Meeting, Rutgers University, New Brunswick, NJ, March 17-19, 1995.
E. E. HOFMANN, ``A Review of Predictive Modeling for Coastal Marine Ecosystems,'' Florida State University, Department of Oceanography Seminar Series, April 14, 1995.
E. E. HOFMANN, ``Modeling for Estuarine Synthesis,'' SCOPE Workshop on Estuarine Synthesis, Beckman Center, Irvine, CA, February 23-25, 1995.
E. E. HOFMANN, E. N. Powell, Rutgers University, and J. M. Klinck, ``Modeling Diseased Oyster Populations,'' Marine Benthic Ecology Meeting, Rutgers University, New Brunswick, NJ, March 17-19, 1995.
E. E. HOFMANN, "A Review of Predictive Modeling for Coastal Marine Ecosystems," Ocean Science Seminar, NOAA/National Ocean Service, Silver Spring, MD, May 10, 1995.
A. D. KIRWAN, JR., ``Critical Points, an Element in the Intersection of Dynamical Systems and Oceanography,'' workshop on Dynamical Systems and Oceanography, CalTech, Pasadena, CA, April 29, 1995.
S. B. Hooker, NASA/Goddard Space Flight Center, Greenbelt, MD, A. D. KIRWAN, JR., B. L. Lipphardt, Jr. and J. Brown, RSMAS, University of Miami, ``Observations of Multipole Vortex Systems from the South Atlantic,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
S. B. Hooker, NASA/Goddard Space Flight Center, Greenbelt, MD, A. D. KIRWAN, JR. and R. P. Mied and G. J. Lindemann, both of the Naval Research Laboratory, Washington, DC, ``Nonlinear Dynamics of Oceanic Dipoles,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
L. M. Ivanov, Ukrainian Academy of Sciences, Sevastopol, Ukraine and A. D. KIRWAN, JR., ``Prediction in Hydrodynamics as a Classical Probabilistic Problem: The First Passage of the Boundary,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
L. M. Ivanov, Ukrainian Academy of Sciences, Sevastopol, Ukraine and A. D. KIRWAN, JR., ``Spectral Representation of the Thermohydrodynamical Characteristics in Complex Geophysical Flows,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
L. M. Ivanov, Ukrainian Academy of Sciences, Sevastopol, Ukraine, A. D. KIRWAN, JR., and T. M. Margolina, Ukrainian Academy of Sciences, Sevastopol, Ukraine, ``On Spectral Reconstruction of the Scalar Fields in Physical Oceanography,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
J. J. Holdzkom II and A. D. KIRWAN, JR., ``Nonlinear Behavior of a Warm Core Ring,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
R. P. Mied, C. Y. Shen, and G. J. Lindemann, all of the Naval Research Laboratory, Washington, DC, and A. D. KIRWAN, JR., ``Secondary Circulations Within Internal Bores,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
A. D. KIRWAN, JR. and B. L. Lipphardt, Jr., ``Geometric Aspects of Rotating Multipole Vortices,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
J. M. KLINCK, E. N. Powell, Rutgers University, and E. E. Hofmann, ``A Hydrodynamic-Oyster Population Model for Galveston Bay, Texas,'' Marine Benthic Ecology Meeting, Rutgers University, New Brunswick, NJ, March 17-19, 1995.
J. M. KLINCK, ``Cross Shelf Transport Driven by Flow Over Submarine Canyons,'' 20th General Assembly of the European Geophysical Society, Hamburg, Germany, April 3-7, 1995.
M. KOBAYASHI, Visiting Faculty Member of CCPO and Professor of Yokohama College of Commerce, Yokahama, Kanagawa, Japan, E. E. Hofmann, E. N. Powell, Rutgers University, and J. M. Klinck, ``Modeling Population Dynamics of the Japanese Oyster,'' Marine Benthic Ecology Meeting, Rutgers University, New Brunswick, NJ, March 17-19, 1995.
M. KOBAYASHI, Visiting Faculty Member of CCPO and Professor of Yokohama College of Commerce, Yokohama, Kanagawa, Japan, E. E. Hofmann, E. Powell, Rutgers University, J. M. Klinck, and K. Kusaka, Okayama Prefectural Institute of Fisheries, Ushimado, Oku-gun, Okayama, Japan, ``Modeling Studies of Japanese Oyster (Crassostrea gigas) Population Dynamics at a Mariculature Site. I: Parameterization of Biological Processes for Hinase Water Populations,'' Japanese Society of Fisheries Science, Tokyo University of Fisheries, Tokyo, Japan, April 2-4, 1995.
M. KOBAYASHI, Visiting Faculty Member of CCPO and Professor of Yokohama College of Commerce, Yokohama, Kanagawa, Japan, E. E. Hofmann, E. Powell, Rutgers University, J. M. Klinck, and K. Kusaka, Okayama Prefectural Institute of Fisheries, Ushimado, Oku-gun, Okayama, Japan, ``Modeling Studies of Japanese Oyster (Crassostrea gigas) Population Dynamics at a Mariculature Site. II: Application of a Time-Dependent Model,'' Japanese Society of Fisheries Science, Tokyo University of Fisheries, Tokyo, Japan, April 2-4, 1995.
J. L. MILLER, ``Overview of General Circulation in the Western Atlantic,'' 1996 International Oceanographic Commission Baseline Survey planning group, Center for Coastal Physical Oceanography, Norfolk, VA, February 18-19, 1995.
J. L. MILLER, "A Mechanism for Inter-Estuary Coastal Exhcnage," 1995 Spring AGU Meeting, Baltimore, MD, June 1, 1995.
E. N. Powell, Rutgers University, E. E. Hofmann, J. M. Klinck, and M. M. DEKSHENIEKS, ``The Fate of Galveston Bay Oyster Populations in the First 50 Years of the 21st Century Under the Texas Water Plan,'' Second Annual Marine and Estuarine Shallow Water Science and Management Conference, Atlantic City, NJ, April 5, 1995.
E. A. SMITH, ``Estimating Sea Surface Temperature from Thermal-Infrared Data from the Advanced Very High Resolution Radiometer,'' invited lecture at the U.S. Naval Academy, Annapolis, MD, March 15, 1995.
E. A. SMITH, "Validation of Pathfinder AVHRR Sea Surface Temperature Estimates, 1995 Spring AGU Meeting, Baltimore, MD, May 29-June 2, 1995.
J. Vazquez of Jet Propulsion Laboratory and E. A. SMITH, "A Comparison of Sea Surface Temperature Data from the NOAA/NASA AVHRR Pathfinder Oceans Prject and Sea Level Data from the Geosat Altimeter in the Gulf Stream," poster presented at 1995 Spring AGU Meeting, Baltimore, MD, May 29-June 2, 1995.
A. VALLE-LEVINSON and K. Lwiza of State University of New York, Stony Brook, NY, "Bathymetric Influences on Hydrographic and Flow Distributions in the Lower Chesapeake Bay," in the colloquium on Processes in Regions of Freshwater Influence, at the 27th International Liege Colloquium on Ocean Hydrodynamics, Liege, Belgium, May 8-12, 1995.
A. VALLE-LEVINSON and Shelly Paraso, "Meteorological Influences on Sea Level and Water Temperature in the Lower Chesapeake Bay: 1992," 1995 Spring AGU Meeting, Baltimore, MD, June 1, 1995.
G. H. WHELESS, "Tidal Exchange Through a Narrow Inlet," 1995 Spring AGU Meeting, Baltimore, MD, June 1, 1995.
K. D. Leaman and P. S. Vertes, both of RSMAS, L. P. ATKINSON, T. N. Lee, RSMAS, and P. Hamilton and E. Waddell, both of Science Applications International Corporation, Raleigh, "Transport, Potential Vorticity, and Current/Temperature Structure Across Northwest Providence and Santaren Channels and the Florida Current off Cay Sal Bank," Journal of Geophysical Research, Vol. 100(C5), 8,561-8,569, May 15, 1995.
T. N. Lee, K. Leaman, and E. Williams, all three of RSMAS, T. Berger, Science Applications International Corporation, Raleigh, and L. P. ATKINSON, "Florida Current Meanders and Gyre Formation in the Southern Straits of Florida," Journal of Geophysical Research, Vol. 100(C5), 8,607-8,260, May 15, 1995.
G. T. CSANADY and J. L. Pelegri, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain, ``Vorticity Balance of Boundary Currents,'' Journal of Marine Research, 53(2), March 1995.
L. M. Lawson, East Tennessee State University, Y. H. SPITZ and E. E. HOFMANN, and R. B. Long, "A Data Assimilation Technique Applied to a Predator-Prey Model, Bulletin of Mathematical Biology, 57(4), 593-617, 1995.
J. L. MILLER and T. N. Lee, Rosenstiel School of Marine and Atmospheric Science, ``Gulf Stream Meanders in the South Atlantic Bight, 1. Scaling and Energetics,'' Journal of Geophysical Research, 100(C4), 6,687-6,704, April 15, 1995.
J. L. MILLER and T. N. Lee, Rosenstiel School of Marine and Atmospheric Science, ``Gulf Stream Meanders in the South Atlantic Bight, 2. Momentum Balances,'' Journal of Geophysical Research, 100(C4), 6,705-6,723, April 15, 1995.
J. W. Murray, University of Washington, L. A. CODISPOTI, and G. E. Friederich, Monterey Bay Aquarium Research Institute, "Oxidation-Reduction Environments: The Suboxic Zone in the Black Sea," ACS Advances in Chemistry Series No.\ 244, Aquatic Chemistry: Interfacial and Interspecies Processes, eds: C. P. Huang, C. R. O'Melia, and J. J. Morgan, 157-176, 1995.
G. H. WHELESS and J. M. KLINCK, ``The Evolution of Density Driven Circulation Over Sloping Bottom Topography,'' Journal of Physical Oceanography, 25(5), 888-901, May 1995.
Editor ........................Carole E. Blett Technical Editor ..............Julie R. Morgan Design Editor .................Carole E. Blett Distribution Manager ..........Beverly Scott