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Continental shelf waves along the coasts of China
OLR (1988)35 (6)
A. PhysicalOceanography
longest datasets. Sea-level signals in the eastern Pacific appear dominated by propagating Rossby waves, so the variability is coherent, but out of phase by several years. Sea level is coherent on opposite sides of the Atlantic at ~ 6 yrs, but this is suspected to be due to direct atmospheric forcing. The amplitude of extremely long-period (40-50 yr) signals is the same as apparent 'rise of sea level over the past century' although the rate of rise is larger, and there is so much variability that sea-level data must be treated carefully in space as well as time to avoid contaminating the 'sea-level rise' signal with propagating signals. Correcting the data for these signals might improve the signal-to-noise ratio and allow better estimates of observed sea-level rise. Until such correction, changes in the rate of sea-level rise on a scale of 10-50 yr cannot be distinguished from background 'noise.' Dept. of Oceanogr., Florida State Univ., Tallahassee, FL 32306, USA. 88:3252 Yanagi, Tetsuo and Hideki Akiyama, 1987. Intermediate-period sea level variabilities along the southwestern coast of Japan. Umi to Sora, 62(4): 153-162. (In Japanese, English abstract.) Dept. of Ocean Engng, Ehime Univ., Matsayama, Japan.
A160. Waves, oscillations 88:3253 Buchwald, V.T. and B.J. Kachoyan, 1987. Shelf waves generated by a coastal flux. A ust. J. mar. Freshwat. Res., 38(4):429-437.
Using zero divergence approximation, the response of a continental shelf to an oscillating coastal current source which acts through a gap of finite width in the coastline is calculated. This response consists of a forced oscillation near the gap with shelf waves appropriate to the shelf on either side. For a shelf of exponential slope and a flux through a channel the dimensions of Bass Strait, the shelf wave response is qualitatively similar to results obtained in the Australian Coastal Experiment, supporting the contention that Bass Strait is a dominant source of shelf waves on the East Australian continental shelf. The 'eddy' mode required to explain the observations may also be attributed to the forced response of the shelf directly off-shore Bass Strait. The effect of adopting, in this physical context, simpler boundary conditions at the shelf edge is investigated. There is some computational simplification, and the results are largely unaffected by this simplification. School of Math., Univ. of New South Wales, P.O. Box 1, Kensington, NSW 2033, Australia.
519
88:3254 Chen, Dake and Jilan Su, 1987. Continental shelf waves along the coasts of China. A cta oceanol, sin. (English version), 6(3):317-334. Spectral analyses on time-series data from 16 tide stations and nearby weather stations during winter 1980-1981 and summer 1981 indicated that after removing wind and barometric effects, the signals of the southward moving sea-level variations were at about 0.21 and 0.32 cpd along the coasts of the Huanghai Sea, East China Sea and South China Sea in winter, and only 0.26 cpd southward along the coast of the South China Sea in summer. Using simple analytical models based on idealized bottom profiles, the observed phenomena can be explained as the lowest-mode continental shelf waves travelling along the coasts of China. Second Inst. of Oceanogr., State Oceanic Admin., Hangzhou, People's Republic of China. 88:3255 Clarke, A.J., 1987. Origin of the coastally trapped waves observed during the Australian Coastal Experiment. J. phys. Oceanogr., 17(11):18471859.
Two analytical models are used to demonstrate that the freely propagating coastally trapped waves (CTW) that dominated the large alongshore-scale low-frequency variability in the Australian Coastal Experiment (ACE) are not due to wave energy propagating freely through Bass Strait from the Southern Australian wave guide, but rather are generated by very strong low-frequency winds in Bass Strait. The first model shows that CTW energy flux from the Southern Australian shelf wave guide does not propagate through Bass Strait. It is either frictionally dissipated at the northwest entrance or travels southward along the western escarpment as 'escarpment' waves, then southward along Tasmania's west coast as coastally trapped waves. The second model calculates the eastward energy flux at the eastern end of Bass Strait assuming all this flux is generated by very strong winds in Bass Strait. Calculations show that the size of this flux is consistent with the amount entering the ACE region. Dept. of Oceanogr., Florida State Univ., Tallahassee, FL 32306, USA. 88:3256 Dommermuth, D.G. and D.K.P. Yue, 1987. A high-order spectral method for the study of nonlinear gravity waves. J. Fluid Mech., 184:267288. A robust numerical method is based on the Zakharov equation/mode-coupling idea but is generalized
A. PhysicalOceanography
longest datasets. Sea-level signals in the eastern Pacific appear dominated by propagating Rossby waves, so the variability is coherent, but out of phase by several years. Sea level is coherent on opposite sides of the Atlantic at ~ 6 yrs, but this is suspected to be due to direct atmospheric forcing. The amplitude of extremely long-period (40-50 yr) signals is the same as apparent 'rise of sea level over the past century' although the rate of rise is larger, and there is so much variability that sea-level data must be treated carefully in space as well as time to avoid contaminating the 'sea-level rise' signal with propagating signals. Correcting the data for these signals might improve the signal-to-noise ratio and allow better estimates of observed sea-level rise. Until such correction, changes in the rate of sea-level rise on a scale of 10-50 yr cannot be distinguished from background 'noise.' Dept. of Oceanogr., Florida State Univ., Tallahassee, FL 32306, USA. 88:3252 Yanagi, Tetsuo and Hideki Akiyama, 1987. Intermediate-period sea level variabilities along the southwestern coast of Japan. Umi to Sora, 62(4): 153-162. (In Japanese, English abstract.) Dept. of Ocean Engng, Ehime Univ., Matsayama, Japan.
A160. Waves, oscillations 88:3253 Buchwald, V.T. and B.J. Kachoyan, 1987. Shelf waves generated by a coastal flux. A ust. J. mar. Freshwat. Res., 38(4):429-437.
Using zero divergence approximation, the response of a continental shelf to an oscillating coastal current source which acts through a gap of finite width in the coastline is calculated. This response consists of a forced oscillation near the gap with shelf waves appropriate to the shelf on either side. For a shelf of exponential slope and a flux through a channel the dimensions of Bass Strait, the shelf wave response is qualitatively similar to results obtained in the Australian Coastal Experiment, supporting the contention that Bass Strait is a dominant source of shelf waves on the East Australian continental shelf. The 'eddy' mode required to explain the observations may also be attributed to the forced response of the shelf directly off-shore Bass Strait. The effect of adopting, in this physical context, simpler boundary conditions at the shelf edge is investigated. There is some computational simplification, and the results are largely unaffected by this simplification. School of Math., Univ. of New South Wales, P.O. Box 1, Kensington, NSW 2033, Australia.
519
88:3254 Chen, Dake and Jilan Su, 1987. Continental shelf waves along the coasts of China. A cta oceanol, sin. (English version), 6(3):317-334. Spectral analyses on time-series data from 16 tide stations and nearby weather stations during winter 1980-1981 and summer 1981 indicated that after removing wind and barometric effects, the signals of the southward moving sea-level variations were at about 0.21 and 0.32 cpd along the coasts of the Huanghai Sea, East China Sea and South China Sea in winter, and only 0.26 cpd southward along the coast of the South China Sea in summer. Using simple analytical models based on idealized bottom profiles, the observed phenomena can be explained as the lowest-mode continental shelf waves travelling along the coasts of China. Second Inst. of Oceanogr., State Oceanic Admin., Hangzhou, People's Republic of China. 88:3255 Clarke, A.J., 1987. Origin of the coastally trapped waves observed during the Australian Coastal Experiment. J. phys. Oceanogr., 17(11):18471859.
Two analytical models are used to demonstrate that the freely propagating coastally trapped waves (CTW) that dominated the large alongshore-scale low-frequency variability in the Australian Coastal Experiment (ACE) are not due to wave energy propagating freely through Bass Strait from the Southern Australian wave guide, but rather are generated by very strong low-frequency winds in Bass Strait. The first model shows that CTW energy flux from the Southern Australian shelf wave guide does not propagate through Bass Strait. It is either frictionally dissipated at the northwest entrance or travels southward along the western escarpment as 'escarpment' waves, then southward along Tasmania's west coast as coastally trapped waves. The second model calculates the eastward energy flux at the eastern end of Bass Strait assuming all this flux is generated by very strong winds in Bass Strait. Calculations show that the size of this flux is consistent with the amount entering the ACE region. Dept. of Oceanogr., Florida State Univ., Tallahassee, FL 32306, USA. 88:3256 Dommermuth, D.G. and D.K.P. Yue, 1987. A high-order spectral method for the study of nonlinear gravity waves. J. Fluid Mech., 184:267288. A robust numerical method is based on the Zakharov equation/mode-coupling idea but is generalized