728 A Physical Occanograph?, OLR (1985) 32 (9)

flection and bottom friction set up a boundary layer at the western boundary of the basin but not on the eastern flank of the ridge. When the forcing is not zonally uniform, the position of the maximum of the wind-stress curl relative to the ridge appears to significantly influence ocean response. Inst. de Mecanique, CNRS, BP53, Grenoble 38041, France.

85:4950 Basco, D.R., 1985. A qualitative description of wave

breaking. J. WatWay Port coast. Ocean Engng. Am. Soc. civ. Engrs, 111(2):i71-188.

Both classic spilling and plunging-type breakers have similar initial breaking motions, but at vastly different scales. A plunger vortex is initially created by the overturning jet, which in turn causes a splash-up of trough fluid and subsequent formation of a surface vortex similar to the roller in a hydraulic jump. It is hypothesized that the plunger vortex translates laterally to push up a new surface wave with vastly different wave kinematics that continues propagating into the inner surf zone. At the outer or transition region, momentum is being exchanged between mean, periodic and random flow processes along with some energy loss. Evidence from the literature supports the new, second wave hypothesis. Texas A&M Univ., College Station, TX 77843, USA.

85:4951 Bernard, E.N. and H.B. Milburn, 1985. Long-wave

observations near the Gallpagos Islands. J. geophys. Res., 90(C2):3361-3366.

Two bottom pressure recorders were deployed from April to August 1982 at 2.5°S, 95.0°W in 3751-m depth and at 0.5°S, 89.5°W in 16-m depth to ascertain the background level of wave energy in the period range of 4-90 min. Preliminary analysis reveals the instrument is capable of detecting: (1) tsunamis as small as 1 cm in the open ocean and (2) disturbances from distant hurricanes. PMEL, NOAA. Seattle, WA, USA.

85:4952 Bullock, G.N. and Ian Short, 1985. Water particle

velocities In regular waves. J. WatWay Port coast. Ocean Engng, Am. Soc. cir. Engrs, 111(2):189- 200.

Eulerian water particle velocities under waves in a closed channel are not always accurately predicted by a conventional application of Stokes' first, second or fifth order wave theory. Amplitudes predicted for the second harmonics of the velocity components can be over 100% in error. There is a mean horizontal velocity which is often greater than the amplitude of the second harmonic and can be 20% of

the amplitude of the first harmonic. Because the design of a wave facility influences the particle kinematics, local empirical data will generally be required to achieve accurate predictions. Plymouth Polytech., Plymouth, UK.

85:4953 Chaplin, J.R., 1985. Morison inertia coefficients in

orbital flow. J. Wat Way Port coast. Ocean Engng, Am. Soc. cir. Engrs, 111(2):201-215. Univ. of Liverpool, P.O. Box 147, Liverpool, UK.

85:4954 Chereskin, T.K. and E. Mollo-Christensen, 1985.

Modulational development of nonlinear gravity- wave groups. J. Fluid Mech., 151:337-365.

Amplitude and phase modulations are calculated using Hilbert-transform techniques. With increasing propagation distance and wave steepness, phase modulation develops local phase reversals whose locations correspond to amplitude minima or nodes. The concomitant frequency modulation develops jumps or discontinuities. Observations are modelled numerically to examine the evolution of modulation and to test the inviscid predictions for the asymp- totic behaviour of groups versus long-time obser- vations. Although dissipation rules out recurrence, there is a long-time coherence of the groups. Phase modulation distinguishes between dispersive and soliton behaviour. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA.

85:4955 Choi, Injune, 1984. An effect of drift current on

generation stage of wind waves. J. oceanol. Soc. Korea, 19(2): 195-199.

Adding the effect of drift current to Phillips' (1957) theory on first stage wave generation by wind shows that drift current significantly modifies the results, especially the resonance condition and wave spec- trum. Dept. of Phys., Hankuk Univ. of Foreign Stud., Seoul 131, Korea. (msg)

85:4956 Fenton, J.D., 1985. A fifth-order Stokes theory for

steady waves. J. WatWay Port coast. Ocean Engng, Am. Soc. cir. Engrs, 111(2):216-234.

An alternative Stokes theory for steady waves in water of constant depth is presented where the expansion parameter is the wave steepness itself. In addition to wave height, period and water depth, it is also necessary to specify the current or mass flux to apply any steady wave theory, the reason being that waves almost always travel on some finite current and the apparent wave period is actually a Doppler- shifted period. Most previous theories have ignored