Diagnosing a partly standing internal wave in Mamala Bay, Oahu

Martini, Kim I.; Alford, Matthew H.; Nash, Jonathan D.; Kunze, Eric; Merrifield, M. A.

doi:10.1029/2007gl029749

Cited by 46 publications

(64 citation statements)

References 13 publications

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“…Differences between model internal wave group speed and theoretical mode-1 group speed are an indication of (partly) standing wave behaviour. c model g < c theory g is expected for standing or partly standing waves (Martini et al, 2007) and is apparent for both Feb09 and Apr09 (Fig. 8c).…”

Section: Hke Ape and Group Speedmentioning

confidence: 80%

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Transition from partly standing to progressive internal tides in Monterey Submarine Canyon

Hall

Alford

Carter

et al. 2014

Deep Sea Research Part II: Topical Studies in Oceanography

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Monterey Submarine Canyon is a large, sinuous canyon off the coast of California, the upper reaches of which were the subject of an internal tide observational program using moored profilers and upward-looking moored ADCPs. The mooring observations measured a near-surface stratification change in the upper canyon, likely caused by a seasonal shift in the prevailing wind that favoured coastal upwelling. This change in near-surface stratification caused a transition in the behaviour of the internal tide in the upper canyon from a partly standing wave during pre-upwelling conditions to a progressive wave during upwelling conditions. Using a numerical model, we present evidence that either a partly standing or a progressive internal tide can be simulated in the canyon, simply by changing the initial stratification conditions in accordance with the observations. The mechanism driving the transition is a dependence of down-canyon (supercritical) internal tide reflection from the canyon floor and walls on the depth of maximum stratification. During pre-upwelling conditions, the main pycnocline extends down to 200 m (below the canyon rim) resulting in increased supercritical reflection of the up-canyon propagating internal tide back down the canyon. The large up-canyon and smaller down-canyon progressive waves are the two components of the partly standing wave. During upwelling conditions, the pycnocline shallows to the upper 50 m of the watercolumn (above the canyon rim) resulting in decreased supercritical reflection and allowing the up-canyon progressive wave to dominate.

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Section: Hke Ape and Group Speedmentioning

confidence: 80%

“…The mode-1 standing internal wave energy equations were generalised to include partly standing waves by Martini et al (2007). For a partly standing mode-1 internal wave, the parallel energy flux is uniform and in the direction of the major (i.e., largest amplitude) component wave.…”

Section: Standing and Partly Standing Internal Wavesmentioning

confidence: 99%

Transition from partly standing to progressive internal tides in Monterey Submarine Canyon

Hall

Alford

Carter

et al. 2014

Deep Sea Research Part II: Topical Studies in Oceanography

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“…The resultant interference patterns may lead to the misinterpretation of energy flux and the direction of wave propagation (Nash et al 2004;Martini et al 2007). However, by comparing the alignment of energy flux to the semimajor axis of the current ellipse (appendix B), we can determine when internal tides are likely dominated by a single wave (aligned) or a mixture of multiple waves (unaligned).…”

Section: B Superposed Internal Tidesmentioning

confidence: 99%

“…The conversion is particularly efficient when barotropic flow is directed across large bathymetric obstacles (St. Laurent et al 2003;Garrett and Kunze 2007), such as the Hawaiian Ridge (Ray and Cartwright 2001;Merrifield et al 2001;Rudnick et al 2003), the Aleutian Ridge (Cummins et al 2001), and Mendocino Escarpment (Althaus et al 2003), but also occurs over small-scale bathymetric roughness (Bell 1975;St. Laurent and Garrett 2002;Legg 2004;Nash et al 2007). For large obstacles, a small fraction of the barotropic tide is converted to high modes, whereas the bulk is converted into low modes (Nash et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…When superposed, internal tides from local and remote sources cannot be easily distinguished. If standing or partly standing internal tides form between locally generated and shoaling internal tides, energy flux may be perpendicular to the direction of wave propagation (Nash et al 2004;Martini et al 2007). Thus, interpretation of a multidirectional wave field can be challenging.…”

mentioning

confidence: 99%

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Observations of Internal Tides on the Oregon Continental Slope

Martini

Alford

Kunze

et al. 2011

Journal of Physical Oceanography

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A complex superposition of locally forced and shoaling remotely generated semidiurnal internal tides occurs on the Oregon continental slope. Presented here are observations from a zonal line of five profiling moorings deployed across the continental slope from 500 to 3000 m, a 24-h expendable current profiler (XCP) survey, and five 15-48-h lowered ADCP (LADCP)/CTD stations. The 40-day moored deployment spans three spring and two neap tides, during which the proportions of the locally and remotely forced internal tides vary. Baroclinic signals are strong throughout spring and neap tides, with 4-5-day-long bursts of strong crossslope baroclinic semidiurnal velocity (u M 2. 0:05 m s 21 ) and vertical displacement (z M 2 . 100 m). Energy fluxes exhibit complex spatial and temporal patterns throughout both tidal periods. During spring tides, local barotropic forcing is strongest and energy flux over the slope is predominantly offshore (westward). During neap tides, shoaling remotely generated internal tides dominate and energy flux is predominantly onshore (eastward). Shoaling internal tides do not exhibit a strong spring-neap cycle and are also observed during the first spring tide, indicating that they originate from multiple sources. The bulk of the remotely generated internal tide is hypothesized to be generated from south of the array (e.g., Mendocino Escarpment), because energy fluxes at the deep mooring 100 km offshore are always directed northward. However, fluxes on the slope suggest that the northbound internal tide is turned onshore, most likely by reflection from large-scale bathymetry. This is verified with a simple three-dimensional model of mode-1 internal tides propagating obliquely onto a near-critical slope, whose output conforms fairly well to observations, in spite of its simplicity.

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Coastal‐trapped behavior of the diurnal internal tide at O'ahu, Hawai'i

2017

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The influence of rotation on the structure and propagation of internal tides around O'ahu, Hawai'i is investigated using in situ observations and a tidally forced, primitive equation model with realistic bathymetry and stratification. Particular attention is given to the diurnal internal tide, which largely has been de‐emphasized in previous studies of the region because of the dominance of the semidiurnal internal tide but has been determined by recent studies to be a significant contributor to baroclinic variability. Though both diurnal and semidiurnal internal tides are generated primarily over Ka'ena Ridge to the northwest of the island, the diurnal internal tide propagates clockwise around the island as an imperfectly trapped wave, while the semidiurnal internal tide propagates away from the ridge, unaffected by rotation. The diurnal and semidiurnal internal tides fall into the superinertial frequency range; however, the diurnal frequency apparently is sufficiently close to inertial (∼ 1.4f) for rotation to affect internal tide propagation. The in situ observations support the model finding that diurnal trapping provides the primary source of baroclinic variability along the eastern coast of the island, a stretch of coastline otherwise sheltered from the internal tide energy generated over the Hawaiian Ridge. The findings in Hawai'i suggest that coastal trapping of superinertial internal tides may be a significant source of variability and mixing in other nearshore systems around the world.

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Diagnosing a partly standing internal wave in Mamala Bay, Oahu

Cited by 46 publications

References 13 publications

Transition from partly standing to progressive internal tides in Monterey Submarine Canyon

Transition from partly standing to progressive internal tides in Monterey Submarine Canyon

Observations of Internal Tides on the Oregon Continental Slope

Coastal‐trapped behavior of the diurnal internal tide at O'ahu, Hawai'i

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