Normal Modes of the World Ocean. Part II: Description of Modes in the Period Range 8 to 80 Hours

Platzman, George W.; Curtis, Gary A.; Hansen, Kirk S.; Slater, Richard D.

doi:10.1175/1520-0485(1981)011<0579:nmotwo>2.0.co;2

Cited by 109 publications

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“…characteristics of the principal mode roughly correspond to the spatial patterns of normal modes of mode 16, mode 26, and mode 39 in Platzman et al (1981). The phase of Antarctic coastal sea levels, which is estimated from this FDEOF analysis, is also overlaid on Fig.…”

Section: November 2014 K U S a H A R A A N D O H S H I M Amentioning

confidence: 80%

“…Some previous modeling studies suggested that there are westward-propagating external Kelvin waves guided by the Antarctic continent (Platzman et al 1981;Zahel and Müller 2005;Müller 2009). Platzman et al (1981) calculated 56 normal modes for the global ocean in the period ranging from 8 to 80 h based on results of a finiteelement barotropic numerical model and suggested that there exist Kelvin waves for wavenumbers 1, 2, and 3 around the Antarctic continent.…”

Section: Introductionmentioning

confidence: 98%

“…Until now, there have been numerous observational studies for internal Kelvin waves, which play substantial roles in a stratified coastal ocean. In contrast, regarding external Kelvin waves, which have a much larger scale and propagate much faster than internal Kelvin waves, the investigations have been very limited, except tidally generated external Kelvin waves (Platzman et al 1981;Müller 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Platzman et al (1981) calculated 56 normal modes for the global ocean in the period ranging from 8 to 80 h based on results of a finiteelement barotropic numerical model and suggested that there exist Kelvin waves for wavenumbers 1, 2, and 3 around the Antarctic continent. The phase speed of external Kelvin waves at 4000-m depth is about 200 m s…”

Section: Introductionmentioning

confidence: 99%

“…These period ranges of the AKWs rarely overlap the diurnal and semidiurnal tidal periods (22.31-28.01 and 11.61-13.17 h). Platzman et al (1981) Fig. 1.…”

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confidence: 99%

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Kelvin Waves around Antarctica

Kusahara

Ohshima

2014

Journal of Physical Oceanography

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The Southern Ocean allows circumpolar structure and the Antarctic coastline plays a role as a waveguide for oceanic Kelvin waves. Under the cyclic conditions, the horizontal wavenumbers and frequencies for circumpolarly propagating waves are quantized, with horizontal wavenumbers 1, 2, and 3, corresponding to periods of about 32, 16, and 11 h, respectively. At these frequencies, westward-propagating signals are detected in sea level variation observed at Antarctic coastal stations. The occurrence frequency of westward-propagating signals far exceeds the statistical significance, and the phase speed of the observed signal agrees well with the theoretical phase speed of external Kelvin waves. Therefore, this study concludes that the observed, westward-propagating sea level variability is a signal of the external Kelvin waves of wavenumbers 1, 2, and 3 around Antarctica. A series of numerical model experiments confirms that Kelvin waves around Antarctica are driven by surface air pressure and that these waves are excited not only by local forcing over the Southern Ocean, but also by remote forcing over the Pacific Ocean. Sea level variations generated over the Pacific Ocean can travel to the western side of the South American coast and cross over Drake Passage to the Antarctic continent, constituting a part of the Kelvin waves around Antarctica.

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Section: November 2014 K U S a H A R A A N D O H S H I M Amentioning

confidence: 80%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…These period ranges of the AKWs rarely overlap the diurnal and semidiurnal tidal periods (22.31-28.01 and 11.61-13.17 h). Platzman et al (1981) Fig. 1.…”

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confidence: 99%

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Kelvin Waves around Antarctica

Kusahara

Ohshima

2014

Journal of Physical Oceanography

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Topographic vorticity waves forced by Antarctic dense shelf water outflows

Marques

Padman

Springer

et al. 2014

Geophysical Research Letters

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We use numerical simulations to investigate excitation of topographic vorticity waves (TVWs) along the Antarctic continental slope by outflows of dense shelf water through troughs. Idealized models show that wave frequency depends on the amount of stretching in the ambient fluid over the outflow and on background along‐slope mean flow. Frequency is higher for steeper bottom slope, larger outflow density anomaly, and stronger westward mean flow. For weak stratification and weak westward along‐slope flows typical of the Antarctic slope, wave energy propagates eastward, in the opposite direction from phase velocity. Our results are consistent with recent observations of TVWs in the southern Weddell Sea. In a realistic simulation of the Ross Sea, TVW properties are modulated on seasonal and shorter time scales as background ocean state varies. We expect these waves to affect mixing, cross‐slope exchanges, and sea ice concentration in the vicinity of sources of dense water outflows.

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The evolution of tides and tidal dissipation over the past 21,000 years

Wilmes

Green

2014

JGR Oceans

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The 120 m sea-level drop during the Last Glacial Maximum (LGM; 18-22 kyr BP) had a profound impact on the global tides and lead to an increased tidal dissipation rate, especially in the North Atlantic. Here, we present new simulations of the evolution of the global tides from the LGM to present for the dominating diurnal and semidiurnal constituents. The simulations are undertaken in time slices spanning 500-1000 years. Due to uncertainties in the location of the grounding line of the Antarctic ice sheets during the last glacial, simulations are carried out for two different grounding line scenarios. Our results replicate previously reported enhancements in dissipation and amplitudes of the semidiurnal tide during LGM and subsequent deglaciation, and they provide a detailed picture of the large global changes in M 2 tidal dynamics occurring over the deglaciation period. We show that Antarctic ice dynamics and the associated grounding line location have a large influence on global semidiurnal tides, whereas the diurnal tides mainly experience regional changes and are not impacted by grounding line shifts in Antarctica.

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Normal Modes of the World Ocean. Part II: Description of Modes in the Period Range 8 to 80 Hours

Cited by 109 publications

References 0 publications

Kelvin Waves around Antarctica

Kelvin Waves around Antarctica

Topographic vorticity waves forced by Antarctic dense shelf water outflows

The evolution of tides and tidal dissipation over the past 21,000 years

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