Physical oceanography

Oceanographic Literature Review (1989) 36 (1) The citations are those received in the editorial office during the period 1-31 October, 1988. Most are accompanied by a short annotation or abstract and, when obtainable, by the first author's address. The citations are classified under six main headings and about 130 sub-headings (see the table of contents). Subject and author indexes are published for the first three quarters of the year with an annual cumulation. See the preface for additional explanatory material.

A. PHYSICAL OCEANOGRAPHY AI0. Apparatus and methods 89:0001 La Violette, P.E. and R.J. Holyer, 1988. Noise and temperature gradients in multichannel sea surface temperature imagery of the ocean. Remote Sens. Environ., 25(2):231-241. A number of effects resulting from routine use of a multispectral algorithm to correct for atmospheric effects in N O A A A V H R R data used to produce multichannel SST (MCSST) imagery are discussed here. A model is presented to support the hypothesis that enhanced channel 4 and 5 noise can account for the observed noise increase, and documentation of diminished SST gradients in MCSST imagery as compared to unprocessed channel 4 and 5 is presented and discussed. NORDA, NSTL, Bay St. Louis, MS 39522, USA. (emm)

89:0002 Naidu, P.S. and Y.V. Reddy, 1988. Modeling of the sea surface for daylight imagery studies. IEEE J1 ocean. Engng, 13(2):81-83. Plastic-coated paper possesses reflectivity characteristics quite similar to those of the surface of water. Such a paper model is suitably illuminated and photographed, yielding physically simulated daylight imagery of the sea surface under controlled conditions. An example of a simulated surface model is described. Dept. of Elec. Communication Engng, Indian Inst. of Sci., Bangalore 560 012, India.

89:0003 Ogishima, Takashi et al., 1987. Hydrographic conditions of the southeast sea off Hokimido ob~rved by satellite infrared images. Analysis of the data obtained by ship and APT [automatic picture

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transmission] during October 1984. I. Bull. Hokkaido reg. Fish. Res. Lab., 51:51-60. (In Japanese, English abstract.) 89:0004 Sanderson, B.G., B.K. Pal and Allan Goulding, 1988. Calculations of unbiased estimates of the magnitude of residual velocities from a small number of drogue trajectories. J. geophys. Res., 93(C7):8161-8162.

The linear regression method of Okubo and Ebbesmeyer (1976) has commonly been used to compute velocity gradients and residual motion; however, they did not properly address the question of how estimates of velocity gradients and residual velocities are biased by using a cluster consisting of a small number of drogues. This problem is addressed here. Dept. of Phys., Memorial Univ., St. John's, NF AIB 3X7, Canada. 89:0005 Watson, A.J. and J.R. Ledwell, 1988. Purposefully released tracers. Phil. Trans. R. Soc., (A)325(1583): 189-200.

Technology and experimental methods in the open ocean with perfluorinated tracers have now advanced to the state where direct-tracer experiments are feasible. The design of open-ocean experiments is discussed. Consideration of the problem of sampling a streaky distribution leads to the conclusion that the period between release and sampling should be several times the eddy-rotation time. Although any number of tracers could be used for such experiments, sulphur hexafluoride seems to have unique advantages over other candidates. Perfluorinated tracers also are well suited to coastal studies and could be used to measure dispersion and air-sea exchange properties. Mar. Biol. Assoc., The Lab., Citadel Hill, Plymouth PLI 2PB, UK. 89:0006 Wingham, D.J., 1988. Onboard correction of mispointing errors in satellite altimeter returns. IEEE Jl ocean. Engng, 13(2):77-81.

This paper is concerned with determining whether useful onboard corrections to satellite altimeter measurements for errors in antenna mispointing can be made. It is shown that with a loop-time response time of about a minute, the bias in altimeter measurements may be removed, but at a cost of decreasing considerably the signal-to-noise ratio (SNR) of the backscattering coefficient. Dept. of Electronic and Elec. Engng, Univ. Coll., London WC1E 7JE, UK.

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89:0007 Wunsch, Carl, 1988. Transient tracers as a problem in control theory. J. geophys. Res., 93(C7):80998110.

The problem of interpreting transient tracer surveys in the ocean is formally identified as corresponding to placing a 'terminal constraint' on a 'distributed system boundary control problem.' The mathematics available in control theory can then be brought to bear on the tracer data. To use a transient tracer to invert for flow and mixing rates involves a two-step process: start with an initial model, found independently, and determine if acceptable boundary conditions drive the model to reproduce the interior transient tracer at the observation times. If the model succeeds in that reproduction, one stops; the model is adequate and need not be changed. Only if this test fails does one obtain constraints on the fluid flow and mixing, which can be invoked in parameter estimation techniques of control theory. Terminal constraint observations can also be used to estimate the tracer concentrations at earlier times using a smoothing filter. Center for Meteorol. and Physical Oceanogr., MIT, Cambridge, MA 02139, USA.

A40. Area studies, surveys 89:0008 Annigeri, G.G., 1980. Further studies on the hydrography of the inshore waters off Karwar [ludial. J. mar. biol. Ass. India, 22(1-2):77-84. Karwar Res. Centre of CMFRI, Karwar, India. 89:0009 Kono, Tokihiro and Naofumi lnoue, 1987. Variation characteristics of surface temperature at coastal hydrographic stations around Hokkaido. Bull. Hokkaido reg. Fish. Res. Lab., 51:61-74. (In Japanese, English abstract.)

Oceanographic and meteorological observations made from 1971 to 1984 were used to investigate seasonal and secular changes of SST; these changes can be classified into Japan Sea, Tugaru Strait, Pacific Ocean, Nemuro Strait, and Okhotsk Sea types according to pattern and variance of annual variation. Seasonal changes of water temperature propagate downward of the current off each station at a speed nearly that of the current speed. At many stations, temperature anomaly changes with 6 yr periods, and coastal temperatures change in the same manner as the offshore fixed points of each area.

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Noble, A., 1980. [hydrographyl Kanara coast 22(1-2):70-76.

A. Physical Oceanography

89:0010 A study on the nearshere water of the Karwar Bay in the North [India]. J. mar. biol. Ass. India, CMFRI, Cochin-682 018, India.

AS0. General hydrography (distribution of common oceanic properties) 89:0011 Luo, Shusen, 1987. SST characteristics over regions of the global ocean currents. Tropic Oceanol., 6(3):78-86. (In Chinese, English abstract.)

Statistical and climatic methods were used to analyze monthly SST data from regions of major ocean currents. A quasi-triennial oscillatory phenomenon was found over all regions of the Kuroshio Warm Current, and in nine other current regions. During El Nifio years SSTs decreased in the west and east Australian and Mexican current areas, while the opposite occurred in other regions; these phenomena were reversed in years of cold SSTs. SST changes near the North Pacific Equatorial Countercurrent occur 1 mo before similar changes in the South Pacific Equatorial Warm Current region. State Meteorol. Admin., People's Republic of China. 89:0012 Packard, T.T. et al., 1988. Formation of the Alboran oxygen minimum zone. Deep-Sea Res., 35(7A): 1111-1118.

The enhanced oxygen minimum in the western Alboran Sea is the result of a chain of processes starting with nutrient injection into the inflowing Atlantic water at the Strait of Gibraltar. These nutrients originate in the outflowing Levantine Intermediate Water, outflowing Mediterranean Deep Water, and inflowing North Atlantic Central Water. They are injected into the inflowing Atlantic surface water by strong mixing at the eastern end of the strait. They move with Atlantic surface waters along the Spanish coast, mix with nutrients upwelling in the northwestern Alboran Sea and stimulate phytoplankton productivity. Sedimentation in the Alboran gyre convergence zone helps to deliver the resultant organic matter to the Levantine Intermediate Water where bacteria metabolize it to CO 2 at the expense of the existing oxygen. This mechanism develops the most intense oxygen minimum zone in the Mediterranean Sea. Bigelow Lab. for Ocean Sci., McKown Point, W. Boothbay Harbor, ME 04575, USA.

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A80. Circulation 89:0013 Bigg, G.R. and P.D. Killworth, 1988. Conservative tracers and the ocean circulation. Phil. Trans. R. Soc., (A)325(1583): 177-187.

Inclusion of chemical tracers in inverse schemes for calculating the ocean circulation leads to a better determined system of constraints to the flow and may result in increased knowledge about mixing processes as well as current systems. A conservative combination of nitrates or phosphates and oxygen uses standard observed quantities; however, although these tracers do add information to more conventional inverse schemes, the present sampling strategy is inadequate for determining the ocean circulation quantitatively due to oceanic variability and the limited spatial coverage of present hydrographic surveys. School of Environ. Sci., Univ. of East Anglia, Norwich NR4 7TJ, UK. 89:0014 Csanady, G.T. and P. Hamilton, 1988. Circulation of slope water. Continent. ShelfRes., 8(5-7):565-624. Results of the recently conducted Mid-Atlantic Slope and Rise (MASAR) experiment conducted on the upper 'Slope Sea,' have been used in combination with previous evidence to formulate a new empirical schema for slope water circulation. Key characteristics include (1) inflow of Coastal Labrador Sea Water across the Grand Banks at 4 x 106 m 3 s i, isopycnal advection from the Gulf Stream thermocline at 6 x 106 m 3 s-~, and total draining eastward; (2) a closed cyclonic gyre in the western Slope Sea carrying ~ 3 x 106 m 3 s ~ southward; and (3) seasonal formation of a pycnostad by convective overturn with a 6-mo flushing time. Dept. of Oceanogr., Old Dominion Univ., Hampton Blvd., Norfolk, VA 23508, USA. 89:0015 Fennel, Wolfgang, 1988. Analytical theory of the steady state coastal ocean and equatorial ocean. J. phys. Oceanogr., 18(6):834-850. 'Two linear stratified models--a coastal ocean on the f-plane and an unbounded equatorial t - p l a n e - with Rayleigh friction and Newtonian cooling are examined.' The problems are analytically tractable, admitting a general solution via Green's function techniques and produced in practice as expansions of vertical modes. Given various idealizations, the expression of solutions as elementary functions is shown to be possible, and the simplified solutions reproduce many of the observed features of the coastal and equatorial current systems. Akad. der

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Wissenchaften, Inst. fur Meeresk., D D R 2530 Rostock Warnemunde, Postfach. 38, DRG. (emm) 89:0016 Hu, Dunxin, 1987. A strategy for studying sheff circulation in China seas: interannnai variability of shelf circulation. Chinese J. Oceanol. Limnol., 5(4):283-288. The routine hydrographical section data on the continental shelf of China seas, accumulated since 1975, can be used to examine the interannual variability of the shelf circulation. An example is given to show there is interannual variability of shelf circulation in the East China Sea and an hypothesis is proposed to describe its origin and its strong correlation with El Nifto events. Inst. of Oceanol., Acad. Sinica, Qingdao, People's Republic of China. 89:0017 Jenkins, W.J., 1988. The use of anthropogenic tritium and helium-3 to study subtropical gyre ventilation and circulation. Phil. Trans. R. Soc., (A)325(1583):43-61. Tritium and 3He data from the Transient Tracers in the Ocean expedition and two other cruises in the subtropical North Atlantic provide a clear picture of gyre circulation, bilayer transport and exchange processes on seasonal to decade timescales, which are important in the context of oceanic CO 2 uptake. Analyses of a two-year time series of 3He measurements made off Bermuda and the implications for vertical transport processes are also discussed. Dept. of Chem., WHOI, Woods Hole, MA 02543, USA. 89:0018 Jensen, T.G., 1986. Barotropic models of the winddriven large scale ocean circulation. Rept Inst. fys. Oceanogr. Kobenhavns Univ., 48:112pp. After giving a brief history of ocean circulation modelling; a large-scale, rigid lid, barotropic model with flat and variable topography is presented. The model is developed using the multigrid method of Jensen (1986), 'which is particularly useful for elliptic boundary value problems when irregular boundaries are given.' The model is generalized to spherical coordinates, nonlinear physics and the presence of islands. It is shown that anomalous circulations develop quickly and forcefully. Florida State Univ., Mesoscale Air-Sea Interaction Group, Tallahassee, FL 32306-3041, USA. (fcs) 89:0019 Kelly, K.A. and D.C. Chapman, 1988. The response of stratified shelf and slope waters to steady

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offshore forcing. J. phys. Oceanogr., 18(6):906925. The most important factor governing the penetration of energy across the slope is the vertical structure of the imposed forcing: a surface-intensified pressure perturbation can penetrate easily onto the upper slope. Increasing the stratification also increases the energy penetration but not as effectively. Diffusion is relatively unimportant. The velocity field over the shelf is depth-independent regardless of the stratification or the location or vertical structure of the forcing function, and relatively little energy penetrates shoreward of the shelf break. WHOI, Woods Hole, MA 02543, USA. 89:0020 Manzella, G.M.R., G.P. Gasparini and Mario Astraldi, 1988. Water exchange between the eastern and western Med|terranean through the Strait of Sicily. Deep-Sea Res., 35(6A):10211035. Water exchange was examined using data gathered during November 1985 to June 1986. The main surface circulation patterns consisted of meanders and haline fronts south of Sicily. Both surface Atlantic Water and Levantine Intermediate Water formed detached parcels during summer, while during winter they spread approximately from the African to the Sic:'lian shelves. A seasonality in the salinity of the Atlantic Water as well as in the transport of both Atlantic and Levantine waters was observed. Computed summer fluxes were of the same order as those found in the literature; those in winter were nearly twice as great. The summer efflux consisted of less dense water than suggested in previous works. Inside the Strait of Sicily, Levantine Water characteristics showed no seasonal variability, a fact that can be explained by a continuous input of Levantine Water with consistent properties. Ist. per 1o Studio della Dinamica delle Grandi Masse, CNR Stazione Oceanogr., La Spezia, Italy. 89:0021 Roether, W. and G. Fuchs, 1988. Water mass transport and ventilation in the northeast Atlantic derived from tracer data. Phil. Trans. R. Soc., (A)325(1583):63-69. A large 3He and tritium data base collected in the northeast Atlantic since 1977 allows construction of extensive tracer distributions on isopycnal surfaces in the main thermocline. A distinct southward increase in tritium-3He age is observed that depicts the outcrop boundaries and allows quantification of the interior transport. This transport is directed toward the south. Univ. of Bremen, FB-I, 2800 Bremen, FRG.

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A. PhysicalOceanography

89:0022 Stramma, Lothar and Gerold Siedler, 1988. Seasonal changes in the North Atlantic subtropical gyre. J. geophys. Res., 93(C7):8111-8118. A study of the gyre structure in the area east of 35°W between 8 ° and 41°N is presented. The geostrophic flow field indicates seasonal variations in shape but no significant changes in the magnitude of volume transports. The eastern part of the gyre has a larger E - W and smaller N - S extension in summer; the center shifts about 2 ° to the south from winter to summer. Inst. fur Meeresk., Univ. Kiel, Dusternbrooker Weg 20, D-2300 Kiel 1, FRG. 89:0023 Wunsch, C., 1988. Eclectic modelling of the North Atlantic. II. Transient tracers and the ventilation of the eastern basin thermocline. Phil. Trans. R. Soc., (A)325(1583):201-236. Renewal rates of thermocline waters are estimated by combining linear quasi-geostrophic dynamics with steady and transient tracers into a unified eclectic, reservoir model. The 2-D model is rejected because it generates oxygen-utilization rates (OUR) that are, by conventional biological wisdom, too high. The 3-D model shows that the OUR is indeterminate, with possible ranges from zero to unacceptably high values. The problem of using transient tracers is mathematically equivalent to that of distributed-system boundary-control theory, the open-ocean boundary conditions playing the role of the unknown control variables. Some speculation is made about conditions under which transient tracers might play a more definitive role. Dept. of Earth, Atmos., and Planetary Sci., MIT, Cambridge, MA 02139, USA.

A90. Currents 89:0024 Aikman, Frank III, H.W. Ou and R.W. Houghton, 1988. Current variability across the New England continental shelf-break and slope. Continent. Shelf Res., 8(5-7):625-651. This year-long current study made south of Cape Cod revealed a mean westward alongshore flow across the moored current meter array. Variability in kinetic energy spectra across the shelf-break and slope, as well as seasonally and with depth, is described. The spectra tend toward red with a strong indication of increased Rossby wave activity. The observed current appears to respond more strongly to alongshore winds in winter and cross-shore winds in summer, although considerable coherence in the

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synoptic band between the cross-shore component of wind stress and currents is observed throughout the year. Lab. d'Oceanogr. Dynamique et de Climatol., Univ. Paris VI, 4 pl. Jussieu, 75005 Paris, France. (emm) 89:0025 Bane, J.M. Jr. et al., 1988. Gulf Stream remote forcing of sheifbreak currents in the Mid-Atlantic Bight. Geophys. Res. Letts, 15(5):405-407. The 'Slope Sea' is the narrow band of ocean between the Gulf Stream and the continental shelf edge in the Mid-Atlantic Bight, composed primarily of slopewater; a closed cyclonic gyre circulates within the upper few hundred meters of its western end. A two-year time series of current measurements has shown that the southwestward flowing shelfbreak currents along the shoreward flank of the gyre are directly related to the position of the Gulf Stream, which is typically 150-300 km seaward of the shelfbreak. The mean monthly shelfbreak currents are strongest, toward the southwest at ~30--40 cm s i, when the stream is within 150 km of the shelf edge, but are close to zero when the stream is ~ 3 0 0 km away. Mar. Sci. Prog., Univ. of North Carolina, Chapel Hill, NC 27599-3300, USA. 89:0026 Butman, Bradford, 1988. Downslope Eulerian mean flow associated with high-frequency current fluctuations observed on the outer continental shelf and upper slope along the northeastern United States continental margin: implications for sediment transport. Continent. Shelf Res., 8(57):811-840.

Eulerian current measurements 5-7 m above bottom show a net downslope flow of 1-5 cm s-~. Although the scalar current speed decreases with water depth and toward the bottom, fluctuations in the crossisobath flow were stronger and increasingly asymmetric near the bottom. Maximum downslope flow exceeded maximum upslope flow by a factor of two to three. Flow characteristics may be caused by differential vertical mixing in the bottom boundary layer where a stratified fluid flows upslope (unstable) and downslope (stable). The asymmetry in current strength clearly favors net downslope transport of sediments that move as bedload. USGS, Woods Hole, MA 02543, USA. 89:0027 Chew, Frank (comment), E.R. Levine, D.N. Connors, P.C. Cornillon and H.T. Rossby (reply), 1988. [Discussion ofl: 'Gulf Stream kinematics along an isopycnal float trajectory.' J. phys. Oceanogr., 18(6):932-935.

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89:0028 Csanady, G.T., J.H. Churchill and Bradford Butman, 1988. Near-bottom currents over the continental slope in the Mid-Atlantic Bight. Continent. Shelf Res., 8(5-7):653-671. Near-bottom currents faster than 0.2 m/s occur frequently over the outer continental shelf of the Mid-Atlantic Bight but very rarely between bottom depths of 500 m and 2 km over the slope. Fast near-bottom currents which do occur over the slope are invariably associated with topographic waves, although it is often superimposed inertial oscillations which increase current speed above the 0.2 m/s level. Topographic waves appear irregularly and vary both along isobaths and in time, presumably a consequence of random generation by Gulf Stream instability. WHOI, Woods Hole, MA 02543, USA.

89:0029 Eidsvik, K.J., 1988. Wind-wave generation of ocean current: on model identification. IEEE Jl ocean. Engng, 13(2):43-49. Stochastic models based upon inertial fluctuations forced by Stokes drift and wind stress may give apparently accurate predictions of surface current. An estimation model capable of following largescale model errors is necessary for reasonably accurate parameter estimates. Still the inertial oscillation damping is easily overestimated. The Stokes drift effect appears to be smaller than the wind stress effect; the latter appears to be uncertain. Norwegian Hydrotech. Lab., N-7034 TrondheimNTH, Norway.

89:0030 Fahrbach, Eberhard and Gerd Wegner, 1987. Observations of persistent pattern in the temperature field related to the North Atlantic Current. Dt. hydrogr. Z., 40(4):141-155. Nine XBT sections are used to study persistence in the general pattern of the North Atlantic Current. A large meander between the Newfoundland Continental Slope and western flank of the Mid-Atlantic Ridge is found in all sections crossing this area. The current seems to follow the topography to the south on the western flank, and to the north on the eastern flank. The 200-kin length scales of mesoscale fluctuations do not vary significantly in different sections, and on the eastern flank of the ridge, appear to consist of meanders which can separate and form closed rings. Although the horizontal gradients vary, the large scale temperature pattern is locally persistent.

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89:0031 Grtlndlingh, M.L., 1988. Review of cyclonic eddies of the Mozambique Ridge Current. S. Afr. J. mar. Sci., 6:193-206. Since 1975, several projects of the NRIO have been aimed at studying eddies in the southwestern Indian Ocean, specifically focused on the cyclonic deep-sea eddies of the region. The results eventually led to discovery of the Mozambique Ridge Current, which was considered responsible for the eddies observed in the vicinity of the Mozambique Ridge. Nine eddies of this current had been located by 1983. The paper summarizes the main characteristics of these eddies and uses as an example an eddy observed and surveyed in April 1983. NRIO, P.O. Box 320, Stellenbosch 7600, South Africa.

IO:0032 Hishida, Masataka, 1987. On southern movement and seasonal variation of Tsugarn Warm Current. Rept hydrogr. Res., Tokyo, 22:1-22. (In Japanese, English abstract.) Seasonal variations in the southward current velocity of the Tsugaru Warm Current and the size of eastward expanding gyres are described here. Classification of expanding gyres into four types on the basis of G E K data is shown equivalent to a classification in terms of monthly 100 m temperature maps and southward current velocity. Maritime Safety Agency, Tokyo, Japan. (emm)

89:0033 Hsueh, Y., 1987. A wind-drlven Yellow Sea warm current? Chinese J. Oceanol. Limnol., 5(4):289298. Observations of current velocity, pressure, and temperature in the eastern Yellow Sea, and geostrophic winds calculated from surface pressure distributions, are analyzed to study the synoptic band response of the Yellow Sea to wintertime winds. Currents along shallow coastal waters are mostly downwind to the south. Along the northern coast the current is persistently northward. In the Yellow Sea trough, strong upwind flows follow closely surges in the north wind. These events are driven by a longitudinal pressure gradient associated with the sea-level set-up along the west coast of South Korea under a prevailing north wind. Dept. of Oceanogr., Florida State Univ., Tallahassee, FL 32306, USA.

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A. PhysicalOceanography

89:0034 Kang, Y.Q., 1988. On the formation of the East Korean Warm Current. Ocean Res., KORDI, 10(1):!-6.

Steady circulation in the East Sea (Japan Sea) driven by inflow through the Korea Strait is studied using a two-layer reduced gravity model on a fl-plane. The East Korean Warm Current, a branch of the Tsushima Current, is a western boundary current associated with the planetary fl-effect and friction. The characteristic width of the EKWC is given by the ratio between the friction coefficient and the planetary /3-effect. Dept. of Oceanogr., Natl. Fish. Univ. of Pusan, Korea. 89:0035 Katoh, Osamu, 1988. Measurement of residual current using the Doppler sonar. Bull. Seikai reg. Fish. Res. Lab., 66:59-67. (In Japanese, English abstract.) Seikai Reg. Fish. Res. Lab., Shimonoseki Branch, Higashi-yamato-machi, Shimonoseki 750, Japan. 89:0036 Lutjeharms, J.R.E. and H.R. Valentine, 1988. On mesuscale ocean eddies at the Agulhas Plateau. S. Afr. J. Sci., 84(3):194-200.

The formation of intense eddies at oceanic fronts may be an important contributory mechanism to meridional heat flow in the ocean. Examples are given of eddies observed at the Sub-Tropical Convergence south of Africa, one of the most intense fronts in the World Ocean. Particular attention is given to eddies formed at the Agulhas Plateau. These particular eddies may make a significant contribution to the nature of the South West Indian Ocean gyre. NRIO, CSIR, P.O. Box 320, Stellenbosch 7600, South Africa. 89:0037 Ma, Jirui, 1987. Rotary spectral estimation and its applied examples for ocean current vector time series. Acta oceanol, sin. (English version), 6(4):510-518.

The mathematical background of the rotary spectral estimation of the ocean current vector and the related rotary variates are described briefly. Some achievements in the confidence intervals of the rotary spectral estimator of the vector are summarized. On this basis, the expectation and variance expressions for the autospectral estimator of the rotary spectrum of vector are derived by resorting to some hypotheses and results of the scalar spectral estimator, and its confidence interval is given. Some

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computation examples for the rotary spectral estimator of vector are furnished. Inst. of Mar. Sci. and Tech. Info., State Oceanic Admin., Tianjin, People's Republic of China. 89:0038 Mosetti, R.A., 1988. Reconstruction of the vertical structure of time-dependent flow from currentmeter data by means of the observer technique. IEEE Jl ocean. Engng, 13(2):50-54.

In the framework of control system theory, some mathematical properties of the partial differential equation that describes the time evolution of the horizontal current as a function of depth enable an observer equation to be defined. This observer equation can be used to reconstruct the vertical current profiles at a given location from the data of current meters moored at fixed depths. Osservatorio Geofisico Sperimentale, 34016 Trieste, Italy. 89:0039 Naganuma, K~suke, 1987. Some areas of fluctuations of the seasonal water temperature in the Tsushima Warm Current region in the Japan Sea. Bull. Japan Sea reg. Fish. Res. Lab., 37:1-11. (In Japanese, English abstract.)

Harmonic analysis of local seasonal fluctuations in water temperatures of the Tsushima Warm Current (surface, 50, 100, and 200 m depths) reveals a complex pattern of amplitudes and phases. Significantly high amplitudes occur only at a period of one year in shallow layers. Phases at both one and half-year periods depend on both the depth and local temperature. Japan Sea Reg. Fish. Res. Lab., Suido-cho, Niigata 951, Japan. (emm) 89:0040 Pedlosky, Joseph, 1988. Entrainment and the termination of the Equatorial Undercurrent. J. phys. Oceanogr., 18(6):880-886.

An ideal fluid model of the Equatorial Undercurrent is modified by the addition of a specified, crossisopycnal entrainment of fluid into the upper mixed layer. Limited to a narrow region straddling the Equator, this entrainment modifies the Bernoulli function value along the Equator. For cases in which the Bernoulli function is rendered constant along the eastern boundary, the transport in the undercurrent is transferred to the upper mixed layer where it exits poleward. Gradual bleeding by entrainment rather than inertial collision may be responsible for the eastern termination of the undercurrent. Dept. of Phys. Oceanogr., WHOI, Woods Hole, MA 02543, USA.

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89:0041 Saunders, P.M., 1988. Bottom currents near a small hill on the Madeira Abyssal Plain. J. phys. Oceanogr., 18(6):868-879.

Near-bottom currents were measured at three sites below 5000 m in the Great Meteor East study area: the top of an abyssal hill, its flank, and an abyssal plain about 30 km away. Results indicate a clockwise vortex trapped over the hill and imply a more important role for time-dependent variations in the large-scale density field than previously thought. Estimates of horizontal diffusivities are obtained from an analysis of current variances on the plain. Estimates of abyssal vertical velocities on the hill and its flanks seem to reflect local bottom slope effects. Inst. of Oceanogr. Sci., Brook Rd., Wormley, Godalming, Surrey GU8 5UB, UK. (emm) 89:0042 Su, Jilan and Wei Wang, 1987. On the sources of the Taiwan Warm Current from the South China Sea. Chinese J. Oceanol. Limnol., 5(4):299-308.

Historical hydrographic data across several sections in the South China Sea and Taiwan Strait have been reconsidered. The year-around existence of the South China Sea Warm Current (SCSWC) along the shelf break off the Guangdong coast and the seemingly yearTaround southwestward current to the east of SCSWC are both evident in the data, which also showed that the northward current in the Taiwan Strait is an extension of SCSWC. A barotropic numerical model is employed to explain some of the observed features. Second Inst. of Oceanogr., SOA, Hangzhou, People's Republic of China. 89:0043 Sun, Daoyuan and Yongting Dong, 1988. A study of numerical model equations of circulations in East China Sea. Acta oceanol, sin. (English version), 7(1): 148-157.

This paper addresses the governing equations for a circulation model for the East China Sea introduced (1980) and defended (1985) by Xi et al. The authors' assertion that these equations were incorrectly formulated is considered in detail. Inst. of Oceanol., Acad. Sinica, Qingdao, People's Republic of China. (emm) 89:0044 Suryanarayana, Ayyagari, G.V. Reddy and Thadathil Pankajakshan et al., 1987. Watermass structure and current system in the equatorial western Indian Ocean during August, 1985. Dr. hydrogr. Z., 40(4): 181-190.

Watermass structure and geostrophic currents in the upper 500 m of the water column were studied in two

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meridional sections between 4°N and 6°S. Westerly flows near the Equator, easterly flows on either side of the Equator, and surface waters from the Arabian and Red seas, and Pacific low salinity water were noticed along the two sections. 89:0045 Webster, lan and Savithri Narayanan, 1988. Lowfrequency current variability on the Labrador Shelf. J. geophys. Res., 93(C7):8163-8173.

To describe the measurements in three frequency bands, a numerical circulation model was developed for the shelf, driven by alongshore and onshore wind stresses and by flow through Hudson Strait. The latter flow is taken to arise from the atmospheric pressure variations over Hudson Bay and from the along-static wind stress over Hudson Strait. The model is quite successful in describing the circulation in the center frequency band (0.18-0.36 cpd), suggesting forcing within this band primarily due to alongshore wind stress and flow through Hudson Strait. The mode I shelf wave dominates the velocity field over the upper shelf, whereas mode 2 dominates flow near the shelf break. Div. of Environ. Mech., CSIRO, GPO Box 821, Canberra, ACT 2601, Australia.

AllO. Water masses and fronts 89:0046 Cember, R.P., 1988. On the sources, formation, and circulation of Red Sea Deep Water. J. geophys. Res., 93(C7):8175-8191.

Existing literature and GEOSECS data are supplemented by new data on the nuclear era history of t4C/~2C ratio in extreme northern Red Sea waters in a qualitative analysis of renewal and internal circulation of Red Sea Deep Water. Two modes of deep water formation (convective and isopycnal) are identified and a simple box model is used to estimate deep water formation rates via both modes as well as oxygen consumption with depth and 3He fluxes in the water column. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. (emm) 89:11047 Houghton, R.W., F. Aikman III and H.W. Ou, 1988. Shelf-slope frontal structure and cross-shelf exchange at the New England shelf-break. Continent. Shelf Res., 8(5-7):687-710.

During the winter frontal motion is associated primarily with wind-driven Ekman forcing across the shelf-break. The foot of the front undergoes 10-20 km cross-shelf excursions which are not correlated

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with current fluctuations over the slope. The crossshelf eddy flux of heat has a large variance but zero mean. During the summer frontal displacements and wind stress diminish. As the seasonal thermocline develops shelf and slope regions become connected by isopycnal surfaces. This appears to facilitate diffusive exchange of shelf and slope water and the formation of submesoscale eddies at the frontal boundary. As the thermocline deepens there appears to be an increase in the eddy flux of heat across the front from the slope to the deep shelf water. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA.

Movements of the Antarctic Intermediate Waters (AIW) associated with the Angola and Agulhas current systems around South Africa are inferred from a study of the T/S characteristics of area waters using data from the South African Data Centre for Oceanography. Key results include regional mean depths of the AIW core, transport characteristics, and the observed en route freshening of AIW waters in both systems. No statistically significant seasonal differences could be resolved. Sea Fish. Res. Inst., Private Bag X2, Rogge Bay 8012, Cape Town, South Africa. (emm)

89:0048 Ou, H.W., F. Aikman III and R.W. Houghton, 1988. Complex empirical orthogonal function analysis of thermistor chain data near a shelf-slope front. Continent. Shelf Res., 8(5-7):711-728.

89:0052 Wolanski, Eric and W.M. Hamner, 1988. Topographically controlled fronts in the ocean and their biological influence. Science, 241(4862): 177-181.

The analysis is carried out for both the winter and summer period over five frequency bands, designated as low frequency, synoptic, diurnal, inertial and semidiurnal. Statistically significant modes are isolated and subjected to physical interpretations. More notable results include the suggestion of baroclinic instability for the low-frequency signal and the generation of standing frontal waves at semidiurnal frequency during the winter period. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA.

Headlands, islands, and reefs generate complex three-dimensional secondary flows that result in physical and biological fronts. Mixing and diffusion processes near these reefs and headlands are quite different from these processes in the open sea, and classical advection-diffusion models developed for the open sea are not valid near shore. Topographically generated fronts affect the sediment distribution, and they aggregate water-borne eggs, larvae, and plankton. This aggregation influences the distribution and density of benthic assemblages and of pelagic secondary and tertiary predators. ©1988 by AAAS. Australian Inst. of Mar. Sci., P.M.B. No. 3, Townsville, M.C., Qld., 4810 Australia.

89:0049 Piepgras, D.J. and S.B. Jacobsen, 1988. The isotopic composition of neodymium in the North Pacific. Geochim. cosmochim. Acta, 52(6): 1373-1381. St. Croix Valley Nat. Gas Co., River Falls, WI 54022, USA. 89:0050 Quadfasel, Detlef, Bert Rudels and Katharina Kurz, 1988. Outflow of dense water from a Svalbard fjord into the Fram Strait. Deep-Sea Res., 35(7A): 1143-1150.

A plume of dense bottom water from Storfjorden in Svalbard spreads northward along the eastern side of Fram Strait. During its descent to depths >2000 m the plume entrains some 500% of surface and intermediate waters. Based on observations from 1986 it appears to contribute about 5-10% to the annual deep water production of the polar basins. Inst. fur Meeresk. der Univ. Hamburg, 2000 Hamburg 54, FRG. 89:0051 Shannon, L.V. and D. Hunter, 1988. Notes on Antarctic Intermediate Water around southern Africa. S. Aft. J. mar. Sci., 6:107-117.

A120. Convergences, divergences, upwelling 89:0053 Jing, Zhenhua et al., 1987. Coastal upwelling and coastal jets in continuously stratified seas. Chinese J. Oceanol. Limnol., 5(4):318-332. Results are presented here for two nonlinear numerical models designed to study mechanisms of coastal upwelling and coastal jets in continuously stratified seas. The first model uses a closed sea with constant bottom, no sea-surface elevation, and constant wind stress, while the second incorporates flat or inclined bottoms, constant or negative wind stress curls, and sea-surface elevations into a semi-infinite basin. In both cases the mathematical analysis rests on the precalculation of the horizontal pressure gradient via a special treatment. Shandong Coll. of Oceanol., Qingdao, People's Republic of China. (emm)

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A. Physical Oceanography

89:0054 Jury, M.R., 1988. A climatological mechanism for wind-driven upwelling near Walker Bay and Danger Point, South Africa. S. Afr. J. mar. Sci., 6:175-181. Dept. of Oceanogr., Univ. of Cape Town, Rondebosch 7700, South Africa.

AI50. Tides and sea level 89:0055 Ekman, Martin, 1988. The world's longest continued series of sea level observations. Pure appl. Geophys., 127(1):73-77.

Sea level data from Stockholm, with the initial year 1774, have been recalculated using old information hitherto not taken into account. Since the resultant series of annual mean sea levels is the longest continued one in the world, and of very good reliability, it is published here. Some results on eustatic changes of sea level, due to changes of climate, are also given. Natl. Land Survey, Div. of Geodetic Res., S-801 82 Gavle, Sweden. 89:0056 Hutchings, J.W. and J.W. Gellen, 1988. The lunar barometric tide in the tropical southwest Pacific. Beitr. Phys. Atmos., 61(2):114-122.

Using the Bartels method and synoptic records (20-30 yr) the average annual lunar barometric tide was determined for sixteen stations in an extensive area of the SW Pacific. Highest amplitude values, >90/~b, are found in the Fiji-Samoa area. Northwest of this area amplitudes are around 75-80 #b and show only a small latitudinal variation. But to the east and northeast, amplitudes decrease rapidly ( ~ 5 0 / ~ b by longitude 155°W). High phase values, > 9 0 °, are found in the far northwestern part of the region, but these decrease markedly toward the southeast (as low as 50 ° near the southern Cook Islands). Comparisons with oceanic tidal data indicate the eastward decrease of lunar tidal amplitude is closely related to the central Pacific oceanic amphidromal system. Karori, Wellington 5, New Zealand. 89:0057 Li, Shuhua and Bo Chen, 1987. A numerical study of the tide and tidal current in Beibu Gulf [South China Sea]. Acta oceanol, sin. (English version), 6(4):519-530. Guangxi Inst. of Oceanol., Beihai, People's Republic of China.

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89:0058 Ou, H.W. and L.R.M. Maas, 1988. Tides near a shelf-slope front. Continent. Shelf Res., 8(57):729-736.

Because of the presence of super-inertial eigenmodes in such a front, the semidiurnal tide is preferentially amplified (relative to the diurnal tide) by generation of the baroclinic tide. Over the Mid-Atlantic Bight where stratification is typically weak, the baroclinic tide only slightly modifies the barotropic tide, nevertheless causing a surface (bottom) intensification of the cross-shelf flow at the diurnal (semidiurnal) frequency. Results compare favorably with observations; implications for tidal mixing in the frontal zone are discussed. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA.

AI60. Waves, oscillations 89:0059 Bryant, P.J., 1988. Cyclic recurrence in nonlinear unidirectional ocean waves. J. Fluid Mech., 192:329-337.

A fully nonlinear model addresses periodic gravity wave groups in deep water, in which the shape of the group envelopes changes cyclically, to describe the slow-time evolution of wave groups and to generalize the cyclic recurrence that can occur during the sideband modulation of Stokes waves and Schr0dinger wave groups. The weak nonlinear interactions concentrate the wave energy at the center of each group at regular intervals, causing waves of greater height locally in space and time; this is suggested as one mechanism for open ocean local wave breaking. The cyclically recurring wave groups may be interpreted as the limit-cycle stage in a progression from uniform wave groups to chaos on the forced, damped, ocean surface. Math. Dept., Univ. of Canterbury, Christchurch, New Zealand. 89:0060 Chen, Junchang and Guoan Li, 1987. Application of the apparent wave spectra of a numerical simulated wave surface in a computation for wave elements in shallow water. Tropic Oceanol., 6(3):57-62. (In Chinese, English abstract.) South China Sea Inst. of Oceanol., Acad. Sinica, People's Republic of China. 89:0061 Csanady, G.T., 1988. Radiation of topographic waves from Gulf Stream meanders. Continent. Shelf Res., 8(5-7):673-686.

In a two-layer model of the Gulf Stream and underlying cold water mass, meander formation and

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pinch-off generates substantial pressure torque on the interface. This transfers vorticity to the lower layer and acts, over a sloping sea floor, as a source term for topographic waves. Source intensity is proportional to the Jacobian of surface pressure and interface elevation. Individual meander pinch-off events radiate topographic waves with characteristics very much as observed. The radiation field is quite unlike a plain monochromatic wave: the perceived frequency of oscillations varies in proportion to distance from the source. Old Dominion Univ., Norfolk, VA 23529, USA. 89:0062

Dalrymple, R.A. and J.T. Kirby, 1988. Models for very wide-angle water waves and wave diffraction.

J. Fluid Mech., 192:33-50. For a bathymetry consisting of parallel bottom contours, wide-angle parabolic models are developed to describe the diffraction of linear water waves. The validity of conventional forms of the parabolic model is extended for wave angles up to 70 ° from the assumed wave direction, Through the use of Fourier decomposition, wave models valid to 90" are developed for three different lateral boundary conditions. Examples are shown for oblique waves through a gap, directional seas past a breakwater, a plane wave with varying crest amplitude, and finally for the diffraction of waves into a channel. Dept. of Civ. Engng, Univ. of Delaware, Newark, DE 19716, USA. 89:0063

Golin'ko, V.I., 1987. Coastal run-up of a tsunami propagating in a hay. Izv. Atmos. Ocean Phys. (a translation of Fiz. Atmos. Okeana), 23(6):486491. Gor'kiy Polytechnical Inst., USSR. 89:0064

Guedes Soares, C., 1988. Comments on 'Parameters of J O N S W A P spectral model for surface gravity waves. II. Predictability from real data,' [by S. Aranuvachapun, Ocean Engng 14(2), 101-115

(1987)1. Ocean Engng, 15(3):289-290. Shipbuilding Engng Prog., Tech. Univ. of Lisbon, 1096 Lisbon, Portugal. 89:0065 Gutshabash, Ye.S. and O.Yu. Smirnov, 1987. Numerical estimates of the rate of nonlinear energy transfer in wind wave spectra. Izv. Atmos. Ocean

Phys. (a translation of Fiz. Atmos. Okeana), 23(6):479-485. An algorithm is suggested for calculating the rate of nonlinear transfer of energy in a wind wave spectrum which is valid for sufficiently narrow angular

11

distributions, and numerical results are shown. An interpretation of the calculations is given, and the range of applicability for the method is indicated. State Oceanogr. Inst., Leningrad Branch, USSR. 89:0066

Hogan. S.J., Idith Gruman and M. Stiassnie, 1988. On the changes in phase speed of one train of water waves in the presence of another. J. Fluid

Mech., 192:97-114. It is shown that the change in phase speed of each wavetrain is directly proportional to the square of the amplitude of the other. In the case of gravitycapillary waves, the correct form of the Zakharov kernel is used to find the expressions for the changes in phase speed and results are checked using a perturbation method; agreement to 6 significant digits is obtained. Full numerical results in the form of polar diagrams over a wide range of wavelengths, away from conditions of triad resonance, are provided. Math. Inst., Univ. of Oxford, St. Giles, Oxford, OX! 3LB, UK. 89:0067

Hwang, C.-H. and F.L.W. Tang, 1988. Wave transmission by overtopping due to random waves.

Ocean Engng, 15(3):261-270. Experimental studies of wave transmission by overtopping for a smooth impermeable breakwater with 1:1.5 slope under both regular and random waves were conducted. A resulting relationship between the transmission coefficient and a breakwater height above mean water level normalized with the height of wave run-up is reported. The transmitted significant wave period by overtopping of random waves may be much longer than those of the incoming wave, especially prominent when the breakwater height to water depth ratio is greater than 0.23 and the incoming wave period is longer than 8 sec. Inst. of Harbor and Mar. Tech., WuChi, Taichung District, Taiwan.

89:0068

Jansons, K.M. and E.R. Johnson, 1988. Topographic Rossby waves above a random array of seamountains. J. Fluid Mech., 191:373-388.

Nonlinear modifications of a normal mode solution of the topographic wave equation for a single mountain by neighboring features is considered here. A large-separation approximation is obtained in the case of a pair of circular mountains and extended to the effects of an infinite set of randomly distributed neighbors. The notion of an effective topography is introduced to describe the structure of the resulting

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ensemble-averaged stream function. Dept. of Math., Univ. Coll., Gower St., London WCIE, 6BT, UK. (emm) 89:0069 Jiang, Decai and Anle Ye, 1988. The application of wave refraction-diffraction model with friction. Acta oceanol, sin. (English version), 7(1):17-26.

OLR(1989)36(I)

can be determined by using the Hilbert Transformation. Error characteristics in the Hilbert Transformation of the field wave record are investigated for a simple wave component. Errors can be reduced by increasing the convolution limit and reducing the sampling interval. Ocean Environ. Engng Lab., KORDI, Seoul, Korea.

A refraction-diffraction model with friction is used to compute wave characteristics in a region near a certain port. Compared with the results from a refraction model, and with data from a 1985 typhoon, the characteristics derived are reasonable, and the results are in good agreement with observations, suggesting that the model is effective for computing coastal wave characteristics over complicated bottom topography. Shandong Coll. of Oceanol., Qingdao, People's Republic of China.

89:0073 Li, Manqiu, Qinggui Cai and Guoan Li, 1987. Distribution of heights and periods of waves during typhoon in the sea area near Hong Kong. Tropic Oceanol., 6(3):48-56. (In Chinese, English abstract.) South China Sea Inst. of Oceanol., Acad. Sinica, People's Republic of China.

89:0070 Keller, J.B., 1988. Resonantly interacting water waves. J. Fluid Mech., 191:529-534.

The time series of shoreline variations (run-up variations) due to random waves have been measured on uniform sloping beaches with slopes ranging from 1/5 to 1/30 and the energy spectra of the variations (run-up spectra) have been examined. The main characteristics of run-up spectra obtained are: (1) a phenomenon of energy saturation is seen in a high frequency region: and (2) the spectral energy densities are independent of offshore incident wave energy. Only in a low frequency region, the energy densities increase with increasing incident wave energy. Dept. of Civ. Engng, Kyoto Univ, Kyoto 606, Japan.

Coupled nonlinear equations are derived for the amplitudes of two small-amplitude resonantly interacting gravity waves in water of non-uniform depth. Such resonance is possible only for wavelengths long compared to the depth. The same equations are obtained from the exact Euler equations, from the nonlinear shallow water theory, and from the Boussinesq equations. Dept. of Math. and Mech. Engng, Stanford Univ., Stanford, CA 94305, USA.

89:0074 Mase, H., 1988. Spectral characteristics of random wave ran-up. Coast. Engng, Amst., 12(2): 175-189.

89:0071 Kishida, Norifumi and R.J. Sobey, 1988. Stokes theory for waves on linear shear current. J. Engng Mech., Am. Soc. cir. Engrs, 114(8):1317-1333.

89:0075 Naciri, Mamoun and C.C. Mei, 1988. Bragg scattedng of water waves by a doubly periodic seabed. J. Fluid Mech., 192:51-74.

Using the Stokes first definition, comparative predictions are presented for wave number, crest elevation, horizontal velocity, horizontal acceleration, dynamic pressure, mean energy level, and the Stokes drift. Predictions of parameter dependence on dimensionless wave height, dimensionless water depth, dimensionless mean current, and dimensionless vorticity indicate that vorticity at realistic levels is unimportant and that height, depth, and current remain the dominant influences. PentaOcean Constr. Co, Ltd., Tokyo, 112 Japan.

We extend the recent work on Bragg scattering of water waves by I-D parallel bars of sinusoidal profile to 2-D doubly sinusoidal bed waves. The resonance condition governing the phase matching between the incident, scattered and bed waves is much more complicated; for one normally incident wave there can be two reflected waves forming a standing wave in the transverse direction. Solutions for a wide strip of bed waves are discussed. 2-D array of hemispheroids are given, and possible application to the design of submerged breakwaters is suggested. Dept. of Civ. Engng, MIT, Cambridge, MA 02139, USA.

89:0072 Lee, D.-Y., 1988. Errors in the Hilbert Transformation of the finite and discrete wave record. Ocean Res., KORDI, 10(1):131-133. The wave envelope function introduced by Rice (1944) is uniquely defined for a given wave record. It

89:0076 Nishitani, Tatsuo, 1987. Note on wave front set of solutions to non-effectively hyperbolic operators. J. Math. Kyoto Univ., 27(4):657-662.

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89:0077 Panchang, V.G., B. Cushman-Roisin and B.R. Pearce, 1988. Combined refraction-diffraction of short-waves in large coastal regions. Coast. Engng, Amst., 12(2):133-156. A method for solving the combined refractiondiffraction equation in large domains is direct, and eliminates the computer storage problems associated with large matrices obtained in standard methods. This efficiency is obtained at the cost of resolution of the shorter wave components in a direction normal to the incident wave direction. As such, the method is limited by the paraxial approximation encountered in the parabolic equation method of solving the ocean-wave refraction-diffraction problem. But it is possible to accommodate reflecting structures such as seawalls along the downwave boundary of the domain; computational convenience allows application to large coastal regions. Dept. of Civ. Engng, Univ. of Maine, Orono, ME, USA. 89:0078 Satake, Kenji and Kunihiko Shimazaki, 1987. Computation of tsunami waveforms by a superposition of normal modes. J. Phys. Earth, 35(5):409-414. Computation of tsunami waveforms for actual topography is usually made by a time-stepping finite-difference method which needs a long computation time and must be repeated for different initial conditions. We propose here an alternative computation method by a superposition of normal modes. Although the eigenvalue problem to obtain the normal mode solutions needs more memories, once we get the solution, the waveforms can be computed by merely summing up the normal modes with weights determined by the initial condition. Results show that the new method is useful for a completely or almost closed basin including the tsunami source. Dept. of Appl. Phys., Tokyo Inst. of Tech., Tokyo, Japan. 89:0079 Satake, Kenji and Kunihiko Shimazaki, 1988. Free oscillation of the Japan Sea excited by earthquakes. I. Observation and wave-theoretical approach. Geophys. J., 93(3):451-456. Dept. of Appl. Phys., Tokyo Inst. of Tech., Ookayama, Meguro-ku, Tokyo 152, Japan. 89:0080 Satake, Kenji and Kunihiko Shimazaki, 1988. Free oscillation of the Japan Sea excited by earthquakes. II. Modal approach and synthetic tsunamis. Geophys. J., 93(3):457-463. Dept. of Appl. Phys., Tokyo Inst. of Tech., Ookayama, Meguro-ku, Tokyo 152, Japan.

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89:0081 Sun, Fu, 1987. On the joint distribution of the periods and heights of sea waves. Acta oceanol, sin. (English version), 6(4):503-509. Based on the ray theory of waves and the linear model of sea waves, a joint distribution of periods and heights is derived. The theoretical expression has the same merits as those of Longuet-Higgins, but the wave height still exhibits a Rayleigh distribution. Shandong Coll. of Oceanol., Qingdao, People's Republic of China. 89:0082 Weidman, P.D. and R. Zakhem, 1988. Cylindrical solitary waves. J. Fluid Mech., 191:557-573. Dept. of Mech. Engng, Univ. of Colorado, Boulder, CO 80309, USA. 89:0083 Wen, Shengchang et al., 1988. Theoretical wind wave frequency spectra in deep water. I. Form of spectrum. Acta oceanol, sin. (English version), 7(1): 1-16. Theoretical wind-wave spectra have been derived by (1) expressing the spectrum in a series composed of exponential terms, (2) assuming that the spectrum satisfies a high order linear differential equation, (3) introducing proper parameters in the spectrum, and (4) making use of some known characteristics of the wind-wave spectrum such as the law governing the equilibrium range. A simplified spectrum is given for practical use. Inst. of Phys. Oceanogr., Shandong Coll. of Oceanogr., Qingdao, People's Republic of China. 89:0084 Zufiria, J.A., 1988. Oscillatory spatially periodic weakly nonlinear gravity waves on deep water. J. Fluid Mech., 191:341-372. A weakly nonlinear Hamiltonian model is derived from the exact water wave equations to study the time evolution of spatially periodic wavetrains. The model assumes that the spatial spectrum of the wavetrain is formed by only three free waves, i.e. a carrier and two side bands. It is found that not only the permanent form travelling waves and their stability are important in describing the time evolution of the waves, but also a new kind of family of solutions which has two basic frequencies plays a crucial role in the dynamics of the waves. Three is the minimum number of free waves necessary to display chaotic behaviour. Applied Math., Calif. Inst. of Tech., Pasadena, CA 91125, USA.

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AI70. Wind-wave interactions

AIS0. Internal waves and tides

89:0085 Kahma, K.K. and M.A. Donelan, 1988. A laboratory study of the minimum wind speed for wind wave generation. J. Fluid Mech., 192:339-364.

89:0089 Agnon, Yehuda and C,C. Mei, 1988. Excitatiun of long internal waves by groups of short surface waves incident on a barrier. J. Fluid Mech., 192:17-31.

Wave growth at very low wind speeds was higher than predicted by the viscous shear-flow instability theory. Assuming that growth is exponential, the inception wind speed at which the growth rate becomes positive occurred at friction velocity ~ 2 cm/s, somewhat lower than the 4-5 cm/s predicted by theory. However, observed growth rates were close to the theory at higher wind speeds when the waves were higher than 1 ram. The effect of temperature on the wind speed at which the waves become readily visible is appreciable. Estimates show that the Phillips resonance mechanism might be sufficiently effective to generate the observed growth at very low wind speeds. Inst. of Mar. Res., P.O. Box 33, SF-00931, Helsinki, Finland. 89:0086 Kumar, Raj, Abhijit Sarkar and V.D. Gupta, 1988. Wind-wave relationship in the Bay of Bengal and Arabian Sea using Seasat data. Mahasagar, 21(1):1-5.

Results show that the correlation coefficient between the sum of scatterometer-derived wind-generated wave height and average climatic swell, and the altimeter-derived total wave height values is 0.8. The derived wave height values over the Arabian Sea are reasonable, indicating the possibility of preparing wave height maps using scatterometer data over large swath areas. Meteorol. and Oceanogr. Div., Space Applications Centre, Ahmedabad 380 053, India. 89:0087 Merzi, N. and W.H. Graf, 1988. Wind stress over water waves: field experiments on Lake of Geneva. Met. atmos. Phys., 39(1):14-24.

Vertical distribution of wind stress over Lake of Geneva was calculated from fixed platform data (100 m from shoreline at 3 m depth) based on the assumption that that total stress is constant in height and comprised additively of wave-supporting and turbulent stresses. Lab. d'Hydraulique, Ecole P01ytech. Fed., Lausanne, Switzerland. (emm) 89:0088 Wu, Yongcheng, Yimou Wang and Lei Li, 1987. The spectrum characteristics of Bohai Bay wind waves under the influence of cold waves. Chinese J. Oceanol. Limnol, 5(4):370-378. Inst. of Oceanol., Acad. Sinica, Qingdao, People's Republic of China.

The effects of diffraction by a long barrier on second-order long waves forced by sinusoidally modulated short incident waves are examined for a two-layered model ocean. When the group velocity of the short waves lies between the phase velocities of the longest baroclinic and barotropic modes, long internal waves of frequency equal to twice the modulational frequency of the short waves radiate away from the edge ray which divides the geometrical shadow and the illuminated region. The baroclinic wave in particular can penetrate the shadow when the internal long wave is not resonated by short surface waves. Dept. of Math., MIT, Cambridge, MA 02139, USA. 89:0090 Brown, Adrian and J.C. Scott, 1987. Observation of ocean internal waves using echosounders. A coust. Letts, 11(6):108-114. Four downward-looking echosounding sonars o different frequencies were operated simultaneousl 3 in the Rockall Trough, supported by CTD measurements. Results indicate the presence of largeamplitude internal wave packets in the weakly stratified upper ocean; the echosounder data followed these waves precisely. The backscatter depended very strongly on frequency, although it was not possible to discriminate quantitatively between the mechanisms proposed for this phenomenon. Admiralty Res. Establishment, Southwell, Portland, Dorset DT5 2JS, UK. 89:0091 Fan, Zhisong, 1988. The effect of horizontal Coriolis force on internal wave-mean flow interaction. Aeta oceanol, sin. (English version), 7(1):2%42.

MUller's theory (1974, 1976) is revised to include the horizontal component of the Coriolis force in the equations of motion and to consider the role of internal waves at near-inertial frequencies. The appearance of cross diffusion of momentum as a result prevents the absolute separability of vertical and horizontal shear of the mean flow. The use of a revised approximation of effective wave stress (after Ruddick and Joyce 1979) to test the theory shows that low, near-inertial frequency, internal waves play an important role in the effective wave stress. Shandong Coll. of Oceanol., Qingdao, People's Republic of China. (emm)

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89:0092 Fang, Xinhua and Yuzhu You, 1987. The vertical characteristics of internal waves in shallow region of the East China Sea analysed from CTD data. Acta oceanol, sin. (English version), 6(4):493-502. Inst. of Phys. Oceanogr., Shandong Coll. of Oceanol., Qingdao, People's Republic of China. 89:0093 Flagg, C.N., !988. Internal waves and mixing along the New England shelf-slope front. Continent. Shelf Res., 8(5-7):737-756.

Analysis of a 48-day early spring data set consisting of mid-depth and near-bottom current measurements suggests that internal waves play a major role in near-bottom mixing processes in the frontal zone. The spectra reveal a low vertical mode internal wave field propagating normal to isobaths onto the shelf. Primary energy loss occurs in the onshore direction and is of sufficient magnitude to produce (via frictional dissipation) a bottom mixed layer capable of facilitating a sizeable cross-frontal exchange of slope and shelf waters. Dept. of Appl. Sci., Oceanogr. Sci. Div., Brookhaven Natl. Lab., Upton, NY 11973, USA. (emm) 89:0094 Grimshaw, R., 1988. Resonant wave interactions in a stratified shear flow. J. Fluid Mech, 190:357-374.

Resonant interactions between triads of internal gravity waves propagating in a shear flow are considered for the case when the stratification and the background shear flow vary slowly with respect to typical wavelengths. If the medium is only weakly inhomogeneous, then there is a strong resonance and to leading order the resonance conditions are satisfied globally. However, if the medium is strongly inhomogeneous, there is a weak resonance and the resonance conditions can only be satisfied locally on certain space-time resonance surfaces. The equations governing the wave amplitudes in this case are derived, and applied to a study of the hierarchy of wave interactions which can occur near a critical level. School of Math., Univ. of New South Wales, P.O. Box 1, Kensington, NSW 2033, Australia. 89:0095 Shaw, P.-T. and G.T. Csanady, 1988. Topographic waves over the continental slope. J. phys. Oceanogr., 18(6):813-822.

Current meter data taken over the continental slope and upper rise in three cross-isobath sections have been examined for energy distribution, coherence, and phase propagation of topographic waves. A peak at 15 days is present in the energy preserving

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spectrum of the near-bottom currents. Phase propagation is offshore, with little energy in reflected waves. These results are consistent with earlier findings. Onshore energy flux associated with topographic waves is deflected by the continental slope, and wave energy propagates along isobaths on the lower slope and upper rise. The waves are probably generated by meanders in the Gulf Stream. Dept. of Mar., Earth and Atmos. Sci., North Carolina State Univ., Box 8208, Raleigh, NC 27695-8208, USA. 89:0096 Wallace, B.C. and D.L. Wilkinson, 1988. Run-up of internal waves on a gentle slope in a two-layered system. J. Fluid Mech., 191:419-442.

This paper describes the dissipative phase of internal-wave run-up on uniform slopes of 0.030 and 0.054 tad as observed in a series of laboratory experiments. As each wave in the periodic train propagated onto the slope, it steepened and developed into a solitary-like wave before finally overturning. Surrounding fluid was engulfed into the wave as it overturned and the resulting gravitational instability produced considerable turbulence and mixing. The broken wave took the form of a discrete bolus of dense fluid which propagated for some distance up the slope. Bulk parameters which characterize the nature of the bolus were defined and the dependence of these on the incident wave parameters and their behaviour during the run-up phase were examined. Water Res. Lab., Univ. of New South Wales, Manly Vale, NSW, Australia.

A210. Ice 89:0097 McLaren, A.S., 1988. Analysis of the under-ice topography in the Arctic Basin as recorded by the USS Nautilus during August 1958. Arctic, 41(2): 117-126.

Under-ice thickness distribution profiles from nearly continuous acoustic recordings are analyzed statistically, and ice compositions and geographic areas with distinct under-ice characteristics are identified. Results showed that mean under-ice draft was 3.68 m across the Arctic Basin; under-ice topography increases in severity from the Canadian to the Eurasian side of the basin (most severe over the Arctic Mid-Ocean Ridge); the most moderate topography and greatest number of polynyas and leads were in the Canada Basin, and an overall Arctic Basin mean of 2.6% open water/new ice existed. CIRES, Univ. of Colorado, Boulder, CO 80309, USA. (lit)

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A240. Optical properties 89:0098 Gordon, H.R., 1988. Influence of vertical stratification on the distribution of irradiance at the sea surface from a point source in the ocean. Appl. Opt., 27(13):2643-2645. Phys. Dept., Univ. of Miami, Coral Gables, FL 33124, USA. 89:0099 Liu, Wenyao et al., 1987. Measurement of the surface emissivity of turbid waters. Chinese J. Oceanol, Limnol., 5(4):363-369. For interpreting thermal IR imagery of the ocean surface, the emissivity of the sea surface is usually assumed to be constant, but emissivity varies with roughness of the sea surface, and the concentration and type of suspended particulates; variations caused by suspended sediments introduce significant errors in satellite-derived temperature maps of turbid coastal waters. In the laboratory the thermal IR emissivity of water was measured as the suspended sediment concentration was varied from zero to extremely high values. Results indicated that increasing the sediment concentration decreases spectral emissivity within the 8-14/tm waveband. Tianjin Univ., People's Republic of China.

A260. Acoustics 89:0100 Alexandrou, Dimitri and Christian de Moustier, 1988. Adaptive noise canceling applied to Sea Beam sidelobe interference rejection. IEEE Jl ocean. Engng, 13(2):70-76. Dept. of Elec. Engng, Duke Univ., Durham, NC 27706, USA. 89:0101 Bao, Xiaoqi, Qichang Xu and Techao Wang, 1987. An analysis of acoustical scattering from elastic obstacles by finite and boundary element combination approach. Acta oceanol, sin. (English version), 6(4):622-629. Inst. of Acoustics, Acad. Sinica, Beijing, People's Republic of China. 89:0102 Dacol, D.K. and D.H. Berman, 1988. Sound scattering from a randomly rough fluid-solid interface. J. acoust. Soc. Am., 84(1):292-302. U.S. Naval Res. Lab., Code 5160, Washington, DC 20375-5000, USA. 89:0103 Fawcett, J.A., 1988. Effect of course maneuvers on bearings-only range estimation. I E E E Trans.

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Acoust. Speech Signal Process, 36(8):1193-1199. Ocean Acoustics, Defence Res. Establishment Pacific, FMO Victoria, BC V0S 1B0, Canada. 89:0104 Pace, N.G. and H. Gao, 1988. Swathe seabed classification. I E E E Jl ocean. Engng, 13(2):83-90. The degree to which different seabed types may be discriminated using features of the power spectrum of the signals backscattered from the seabed, in a side-scan mode, is evaluated. The statistics derived from the data sample considered suggest that the probability of correctly classifying the six seabed types (sand, mud, clay, gravel, stones, rock) is in excess of 97 percent using the spectral features that are defined. School of Phys., Univ. of Bath, Claverton Down, Bath, UK. 89:0105 Palmer, D.R. et al., 1988. Classical chaos in nonseparable [acoustic] wave propagation problems. Geophys. Res. Letts, 15(6):569-572. Numerical calculations show that acoustic ray paths in a weakly range-dependent deterministic ocean model exhibit chaotic behavior, that is, have an exponentially sensitive dependence on initial conditions. Since the ray equations define a nonautonomous Hamiltonian system with one degree of freedom, these results may be understood in terms of recent advances in classical chaos. The Hamiltonian structure of ray equations in general suggests that chaotic ray trajectories will be present in all types of linear wave motion in geophysics when variables do not separate, as in laterally inhomogeneous media. AOML, NOAA, 4301 Rickenbacker Cswy., Miami, FL 33149, USA. 89:0106 Thorne, P.D., N.G. Pace and Z.K.S. A1-Hamdani, 1988. Laboratory measurements of backscattering from marine sediments. J. acoust. Soc. Am., 84(1):303-309. Measurements of the backscattering coefficient from marine sediments between 10 ° and 90 ° grazing angle were taken, using a side-scan arrangement in a laboratory test tank under well-defined conditions, on three surfaces composed of different mean sediment sizes. Utilizing the statistical descriptions, expressions for the backscattering coefficient are obtained using the Helmholtz-Kirchhoff integral applied to a side-scan configuration, and comparisons are made with the data. For each of the sediment surfaces, moderate agreement is obtained over the measurement region; discrepancies are considered. Proudman Oceanogr. Lab,, Bidston Observ., Birkenhead, Merseyside L43 7RA, UK.

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Physical Oceanography

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89:0107 Voudouri, Evriclea and Ludwik Kurz, 1988. A robust approach to sequential detection. IEEE Trans. Acoust. Speech Signal Process., 36(8): 1200-1210. Dept. of Elec. Engng, Manhattan Coll., New York, NY 10471, USA.

Inst. de Mecanique Statistique de la Turbulence, Marseille, France. (emm)

89:0108 Wilson, G.R., R.A. Koch and P.J. Vidmar, 1988. Matched mode localization. J. acoust. Soc. Am., 84(1):310-320. Applied Res. Lab., Univ. of Texas, Austin, TX 78713-8029, USA.

A formal approach to studying the effect of zonally varying stratification on equatorial wave phenomena, which involves the application of a matching condition to equatorial waves incident on a single zonal discontinuity in a shallow water density field, is developed and extended first to consideration of a general continuously stratified fluid front and then to a series of discrete density intervals. The results demonstrate little substantial change in the energy flux of propagating waves but a nontrivial amplification of equatorial zonal velocity and to a lesser degree a decrease in pressure. Code 671, Goddard Space Flight Center, Greenbelt, MD 20771, USA. (emm)

A290. Physical processes, properties (diffusion, turbulence, etc.) 89:0109 Agenbag, J.3. and L.V. Shannon, 1988. A suggested physical explanation for the existence of a biological boundary at 24°30"S in the Benguela system. S. Afr. J. mar. Sci., 6:119-132. Distributions of shoals, commercial catches and larvae of pelagic fish species in the Benguela ecosystem suggest that a well-defined boundary exists near 24°30"S. Surface distributions of temperature, salinity and chlorophyll revealed no significant longshore gradients that could explain the biological boundary, but the wind data suggest that the rate at which kinetic energy is supplied to the surface layers, and hence the turbulent mixing, decreases substantially north of 24°30"S. Nimbus-7 imagery provides evidence of a complex surface circulation pattern in the same region, which may further increase turbulent mixing. The combined effects of changes in circulation and turbulence/stratification may cause the biological discontinuity. Sea Fish. Res. Inst., Private Bag X2, Rogge Bay 8012, Cape Town, South Africa. 89:0110 Baldy, Serge, 1988. Bubbles in the close vicinity of breaking waves: statistical characteristics of the generation and dispersion mechanism. J. geophys. Res., 93(C7):8329-8248. Variations in the bubble size spectrum with depth and wind speed were measured by laser at and near the interface generated between different breaking wave fields in an experimental facility. Under appropriate conditions, the results are self-consistent and support the distinction between an upper generation zone of maximum bubble concentration and invariant spectral shape, and a lower dispersion zone through which global bubble concentration decreases and slope of the size spectrum increases.

89:0111 Busalacchi, A.J. and M.A. Cane, 1988. The effect of varying stratification on low-frequency equatorial motions. J. phys. Oceanogr., 18(6): 801-812.

89:0112 Chefranov, S.G., 1987. Eddy diffusion of passive impurities. Izv. Atmos. Ocean Phys. (a translation of Fiz. Atmos. Okeana), 23(6):492-493. Inst. of Atmos. Phys., Acad. of Sci., USSR. 89:0113 Garcon, V.C. and J.-F. Minster, 1988. Heat, carbon and water fluxes in a 12-box model of the World Ocean. Tellus, 40B(3):161-177. The 12-box model of the World Ocean proposed by Bolin et al. (1983) does not accommodate heat and salt conservation: whenever equations describing these constraints are added the advection flux between the Antarctic and the Atlantic becomes unrealistically small. When the Atlantic surface ocean box is divided into two domains, one for the South and tropical Atlantic, and one for the temperate North Atlantic, realistic upwelling and downwelling fluxes are obtained, but small fluxes from the Antarctic to the Atlantic remain. Strategies for improving the design of the model are discussed. CNES/GRGS, 18 Ave. Edouard Belin, 31055 Toulouse Cedex, France. 89:0114 H~tkkinen, Sirpa, 1988. A note on chimney formation in ice edge regions. J. geophys. Res., 93(C7): 82"/9-8282. Under upwelling conditions in the marginal ice zone, if a strong surface heat loss is present, formation of a deep convective region is possible resulting from an ever decreasing buoyancy and a rapid deepening of the mixed layer, i.e., a 'chimney.' This chimney does

18

A. Physical Oceanography

not extend to the bottom, but loss of buoyancy would indicate eventual overturning to the bottom in the studied two-layer ocean model where initially a 'fresh' and cold (freezing) mixed layer lies above a stagnant, warm, and saline lower layer. A catalyst for the convection is the ice, which has both a dynamic and thermodynamic interaction with the ocean in the coupled model. The entrainment between the mixed layer and the lower layer consists of both the wind mixing component and the convectively induced entrainment; the latter is necessary in producing the chimney. Univ. Space Res. Assoc., NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. 89:0115 Hogan, S.J., 1988. Note on the bubbles that form at the surface of the highest capillary-gravity waves. Phys. Fluids, 31(8):2366-2368. Graphical evidence is provided that the bubbles that form at the surface of the highest capillary-gravity waves are virtually unaffected by gravity, in agreement with recent work by Longuet-Higgins. The bubble of the highest pure capillary wave is examined in detail. Math. Inst., Univ. of Oxford, 24-29 St. Giles, Oxford OX1 3LB, UK. 89:0116 Hsieh, D.Y., 1988. On dynamics of bubbly liquids. Adv. appl. Mech, 26:63-133. The motion of a liquid containing bubbles, and the behavior of the bubbles (either gaseous or vaporous), are obviously very complex as well as difficult to study. Here, the authors start with 'a rational approach to the general problem, and point out along the way how and where plausible or drastic approximations and assumptions are made.' Covered are the dynamical equations for two-phase fluids, averaging schemes, and the specifics of the equations for bubbly liquids, constitutive relations, governing continuum equations, sound waves in bubbly liquids, finite amplitude wave behavior, and governing physical dynamics such as evaporation and condensation. Div. of Applied Math., Brown Univ., Providence, RI, USA. (fcs) 89:0117 Mourn, J.N., D.R. Caldwell and P.J. Stabeno, 1988. Mixing and intrusions in a rotating cold-core feature off Cape Blanco, Oregon. J. phys. Oceanogr., 18(6):823-833. Detailed vertical profiles of temperature, conductivity, turbulent dissipation, and horizontal currents showed (1) SST changes as large as 2 ° in 1 km (but smaller gradients at depth); (2) a structure in the mean currents resembling that of either a cyclonic

OLR (1989) 36 ( 1)

eddy or a current meander; (3) a current field in geostrophic balance on scales > 10 km; (4) a region of intrusions on the northern side of the eddy; (5) a concentration of turbulence on the eddy edges and in the region of intrusions (the eddy core was turbulence-free); and (6) a substantial change in the surface structure in 24 hours. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA. 89:0118 Nor, Doron, 1988. The fusion of isolated nonlinear eddies. J. phys. Oceanogr., 18(6):887-905. The interaction of two isolated lens-like eddies in an infinitely deep barotropic layer is studied by means of an inviscid nonlinear model. Qualitative arguments are used to deduce the sequence of morphological changes leading to a single fused vortex. Although nonlinearity and three-dimensionality of the problem render a complete analytical treatment impossible, theoretical and experimental analyses of an eddy interaction with a solid cylinder show that the initialization process inferred qualitatively (intrusion and tentacle formation) is inevitable in the general case. Dept. of Oceanogr., Florida State Univ., Tallahassee, FL 32306, USA. (emm) 89:0119 Seabergh, W.C., 1988. Observations on inlet flow patterns derived from numerical and physical modeling studies. Am. Fish. Soc. Syrup., 3:16-25. Due to its responsibility to provide navigable entrance channels through coastal inlets, the U.S. Army Corps of Engineers has conducted numerous site-specific model studies of tidal inlets and has performed generalized research on tidal inlets. This paper presents some insights about flow patterns at tidal inlets, and the factors that influence those patterns. Coastal Engng Res. Center, U.S. Army Engr Waterways Experiment Station, P.O. Box 631, Vicksburg, MS 39180, USA. 89:0120 Simonot, J.-Y., Eric Dollinger and Herr6 Le Treut, 1988. Thermodynamic-biological--optical coupling in the oceanic mixed layer. J. geophys. Res., 93(C7): 8193-8202. To quantitatively investigate the role of phytoplanktonic blooms in the open ocean in SST prediction, the mixed layer model of Gaspar (1985, 1988) is coupled to a primary production model adapted from Agoumi (1985), allowing an interactive prediction of the upper ocean turbidity, over two seasonal cycles at Ocean Weather Station Romeo ('turbidity' is used for total optical content). Results confirm that the phytoplanktonic seasonal cycle has a significant impact on SST simulation and should

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be taken into account in future upper ocean simulation experiments. Lab. d'Oceanogr. Dynam. et de Climatol., Univ. P. et M. Curie, 4 Place Jussieu, 75252 Paris Cedex 05, France.

89:0121 Wang, D.-P., 1988. Transport model for water exchange between coastal inlet and the open ocean. Am. Fish. Soc. Syrup., 3:9-15. Most previous estuarine models have been based on the assumption of a 2-D flow field, which is quite restrictive for studies of water exchange between inlets and open ocean. An example of using a generalized, 3-D, density-stratified model to simulate the inlet-ocean interaction is presented. Results indicate that dispersal of the outflow plume is the combined effect of tidal, gravity, and wind-driven currents. The model may be used to assess effects of jetty construction on larvae transport. Mar. Sci. Res. Center, SUNY, Stony Brook, NY 11794, USA.

A300. Fluid mechanics 89:0122 Brighton, P.W.M., 1988. Similarity solutions for two-dimensional steady laminar gravity currents. J. Fluid Mech., 192:75-96. Safety and Reliability Directorate, UKAEA, Wigshaw Lane, Culcheth, Warrington WA3 4NE, UK. 89:0123 De Gregorio, S. and G.A. Dalu, 1987. Ageostrophic (two-dimensional) flow of a rotating stratified fluid orographically perturbed. Nuovo Cim., 10C(6):609-630. We consider the perturbation of a stratified rotating fluid due to the crossing of a mountain ridge. The behaviour of the solutions is examined in the primitive Navier-Stokes equations in linear form. We produce the Green's functions of the problem at ground level at any distance from the perturbing ridge, discuss the relative contribution of the different terms, and examine the behaviour of small-scale waves with altitude. Dipart. di Matematica dell'Univ. La Sapienza, Rome, Italy.

89:0124 Dias, Fr6d~ric, J.B. Keller and J.-M. VandenBroeck, 1988. Flows over rectangular weirs. Phys. Fluids, 31(8):2071-2076. Dept. of Math., Worcester Polytechnic Inst., Worcester, MA 01609, USA.

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89:0125 Dritschel, D.G., 1988. Nonlinear stability bounds for inviscid, two-dimensional, parallel or circular flows with monotonic vorticity, and the analogous three-dimensional quasi-geostrophic flows. J. Fluid Mech., 191:575-581. Dept. of Appl. Math. and Theoretical Phys., Univ. of Cambridge, Silver St., Cambridge CB3 9EW, UK. 89:0126 Hedstrom, Katherine and Laurence Armi, 1988. An experimental study of homogeneous lenses in a stratified rotating fluid. J. Fluid Mech., 191:535556. Injection of a homogeneous fluid into a linearly stratified and rotating background fluid produced anticyclonic lenses which were studied for up to 600 rotation periods. Velocity measurements showed that the interior core rotates as a solid body with a decreasing, nearly axisymmetric exterior velocity field. Gill's (1981) model predicts well both the velocity and aspect ratio vs. Rossby number of the lenses. Lens decay occurred in two stages: symmetric rapid spin-down, with an associated half-life of ~ 7 0 rotation periods followed by asymmetric shedding at a nearly constant core Rossby number, Ro ~0.06. Inst. for Naval Oceanogr., NSTL, MS 39529, USA.

89:0127 Kaul, U.K., 1988. Do large structures control their own growth in a mixing layer? An assessment. J. Fluid Mech., 190:427-450. This study makes a specific comparison between two different 2-D free shear layers: the T-layer which develops in time from an initial tangential velocity discontinuity separating the two half-spaces; and the S-layer which develops downstream of the origin where two uniform streams of unequal velocity are brought into tangential contact. The method of comparison is to assume that the vorticity of the S-layer is given parabolically by a Galilean mapping of that of the T-layer; to satisfy the appropriate boundary conditions in the S-layer and to compute the velocity induced at any point in the S-layer by its vorticity field; and to compare this velocity to that which can be derived from the velocity of the T-layer at corresponding points by a Galilean transformation of the velocity itself. Sterling Fed. Systems, NASA Ames Res. Center, Moffett Field, CA 94035, USA.

89:0128 Liu, J.T.C., 1988. Contributions to the understanding of large-scale coherent structures in developing free turbulent shear flows. Adv. appl. Mech., 26:183-309.

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The physical problem of large-scale coherent structures in turbulent shear flows is examined in terms of conservation principles, and thus in terms of the actual dynamics of the problem. Directed at obtaining the most physical information with the least computation, results are necessarily approximations, but can be seen as supplementary to kinematic and numerical approaches. Div. of Engng, Brown Univ., Providence, RI, USA. (fcs) 89:0129 Masuda, KyQya, 1987. Remarks on compatibility conditions for solutions of Navier-Stokes equations. J. Fac. Sci. Univ. Tokyo, 34(1):159-164. 89:0130 Smyth, N.F., 1988. Dissipative effects on the resonant flow of a stratified fluid over topography. J. Fluid Mech., 192:287-312. In the weakly nonlinear, long-wave limit for the case when the flow is near resonance (the basic flow speed is close to a linear long-wave speed for one of the long-wave modes), two types of dissipation are considered: that due to viscosity acting in boundary layers and interfaces and that due to viscosity acting in the fluid as a whole. The effect of changing bottom topography on the flow produced by a force moving at a resonant velocity is also considered. In most cases, these extra effects result in the formation of a steady state, in contrast to the flow without these effects, which remains unsteady for all time. Dept. of Math., Univ. of Wollongong, P.O. Box 1144, Wollongong, NSW 2500, Australia.

Res., 35(6A): 1069-1077. Convection in a rotating square basin is studied in a laboratory experiment in which the convection is driven by non-uniform heating from below. This experimental configuration is thought to be analogous to large-scale convection in the ocean, driven by non-uniform heating at the surface. As in the non-rotating case, the upper region shows relatively small temperature variation. With rotation, this region has cyclonic circulation. Fluid moves from the upper region into the thermal boundary layer near the bottom, and then moves toward and enters the rising region at the warm end of the basin. Phys. Oceanogr. Dept., WHOI, Woods Hole, MA 02543, USA.

89:0132 Timonov, M.B., N.K. Shelkovnikov and A.A. Belobrov, 1987. Pycnocline deformation during topographic cyclogenesis in a two-layer fluid. Izv. Atmos. Ocean Phys. (a translation of Fiz. Atmos. Okeana), 23(6):474-478. There is a raising of the pycnocline over underwater obstacles, its value varying significantly as a function of the stratification characteristics; the displacement of the pycnocline increases with relative thickness of the upper fluid layer and decreases with increasing density difference in the pycnocline. The possibility of using the quasigeostrophic inertial model of topographic cyclogenesis for evaluating the displacement of the pycnocline over obstacles of finite height is explored. Inst. for Phys. of the Earth, Acad. of Sci., USSR.

89:0131 Speer, K.G. and J.A. Whitehead, 1988. A gyre in a non-uniformly heated rotating fluid. Deep-Sea

B. MARINE METEOROLOGY BI0. Apparatus and methods 89:0133 Huffman, G.J., 1988. Modern meteorological computing resources--the Maryland experience. Bull. Am. met. Sot., 69(7):736-742. The University of Maryland Department of Meteorology is developing one of the first computer

systems in meteorology to take advantage of the new networked computer architecture, Elements of the department's system include scientific workstations, local mainframe computers, remote mainframe computers, local-area networks, 'long-haul' computer-to-computer communications, and 'receiveonly' communications. Some background is provided, together with highlights of some lessons