OLR (I 987) 34 (I 1) A. Physical Oceanography 921

87:6057 Brown, Timothy, 1987. Kelvin wave reflection at an

oscillating boundary with applications to the North Sea. Continent. Shelf Res., 7(4):351-365.

A generalization is made to Taylor's North Sea model of Kelvin wave reflection in a closed semi- infinite channel. An oscillatory long-channel flow is introduced at the end boundary to simulate the effects of the Dover Strait or the Southern Bight. It is found that this flow makes a significant contribution to the amplitude and phase of the reflected Kelvin wave and thereby to the position of amphidromies, respectively, across and along the channel. Solutions obtained describe the two amphidromies with closer agreement than Taylor's solution, c /o Dr. U.T. Ehrenmark, Math. Dept., City of London Polytech., 100 Minories, London E.C.3, UK.

87:6058 Cartwright, D.E. and Muhammad Amin, 1986. The

variances of tidal harmonics. Dr. hydrogr. Z., 39(6):235-253.

The variances, or squared standard errors, of estimates of tidal harmonic constants based on monthly or yearly tide gauge data are analyzed in terms of spectral properties of their noise continuum, modelled as exponential cusps E~ superimposed on a smoothly monotonic non-tidal spectrum E 0. The cusps surrounding diurnal tides are dominated by E0, whereas semidiurnal and higher species cusps are fitted by an exponential form for E~ with bandwidth of a few cycles per yr. Variance ratios for diurnal harmonics are somewhat greater than expected, and the corresponding ratios for semidiurnal and higher species are less. As a very rough guide, standard errors of yearly estimates of the larger tidal con- stituents may be predicted as proportional to their mean amplitude in the ratio of 11 mm/m. Inst. of Oceanogr. Sci., Bidston, Merseyside, UK.

87:6059 Godin, Gabriel and Julio Candela, 1987. Tides and

currents in Fury and Hecla Strait [Canadian Arctic]. Estuar. coast. Shelf Sci., 24(4):513-525. 2963 Aries Mews, Mississauga, ON, L5N 2N2, Canada.

87:6060 Inoue, Masamichi and J.J. O'Brien, 1987. Trends in

sea level in the western central equatorial Pacific during 1974--1975 to 1981. J. geophys. Res., 92(C5): 5045-5051.

The spatial pattern of sea level records at nine island stations suggests that the western equatorial Pacific was losing water while the central equatorial Pacific

was gaining water. These trends appear due to the significant weakening of the near-equatorial easterly trades in the central Pacific which took place throughout the period. The trend reversal observed in 1977-1978 in sea level at the island stations located south of the Equator appear due to a similar trend reversal in the strength of the large-scale southeast trades. Australian Inst. of Mar. Sci., PMB 3, Townsville MC, Qld. 4810, Australia.

87:6061 Prandle, D., 1987. The fine-structure of nearshore

tidal and residual circulations revealed by H.F. radar surface current measurements. J. phys. Oceanogr., 17(2):231-245.

Using the Ocean Surface Current Radar (developed by the Rutherford-Appleton Laboratory, U.K.), 30 days of synoptic hourly surface current vectors were obtained for 84 locations within a nearshore region

18 km 2. Tidal analyses data show that the currents associated with the predominant M 2 constituent sweep smoothly and regularly through the area, unaffected by the finer topographic features. Con- tours of the amplitude of the M 2 semi-major axis are mutually consistent to a precision of better than 0.5 cm s t. Inst. of Oceanogr. Sci., Bidston Observ., Birkenhead, Merseyside, L43 7RA, UK.

87:6062 Spillane, M.C., D.B. Enfield and J.S. Allen, 1987.

Intraseasonal oscillations in sea level along the west coast of the Americas. J. phys. Oceanogr., 17(3):313-325.

Hourly observations of coastal sea level at stations from Peru to British Columbia are analyzed for low-frequency content. A space-time contour plot of sea level from 1971 to 1975 shows the meridional structure of the seasonal cycle and variability associated with the 1972-73 El Nifio. Oscillations with intraseasonal periods of 36-73 days are also evident over alongshore distances of several thou- sand km. Spectral methods and empirical orthogonal function analysis in the frequency domain reveal that intraseasonal sea level variability peaks in spectral density along the coasts of South and Central America and Mexico with high coherence from 34°N to at least 12°S. Phase propagation north of the Equator is poleward at 150-200 km/day. The data suggest that the observed oscillation may be a coastally propagating response to remote processes in the equatorial Pacific waveguide. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 9733 l, USA.