Spatial variability of internal waves in an open bay with a narrow steep shelf in the Pacific off NW Mexico
20
Citation
45
Reference
10
Related Paper
Citation Trend
Keywords:
Internal tide
Stratification (seeds)
Barotropic fluid
Barotropic fluid
Internal tide
Forcing (mathematics)
Mode (computer interface)
Cite
Citations (300)
Abstract A detailed energetic estimate of the barotropic and baroclinic semidiurnal internal tides over the Andaman Sea is performed by using the three‐dimensional Massachusetts Institute of Technology general circulation model. Model‐simulated currents and density fields are validated using in situ observations with high temporal resolution from a buoy located at 10.5°N, 94°E. The generation and dissipation regions of internal tides and their propagation in the domain are identified by quantifying the distribution of total tidal energy among generation, radiation, and dissipation. The model simulation suggests that the internal tides are mainly generated in the north of Sumatra coast, in the Sombrero channel, south of the Car Nicobar Island, and north of the Andaman Island. From these generation sites, a portion of the energy propagates into the Andaman Sea and the remainder propagates toward the southern Bay of Bengal. The depth‐integrated baroclinic energy fluxes are found to be a maximum of ~30 kW/m at the major generation sites in the domain. The model‐estimated energy dissipation rates suggest that the maximum amount of energy dissipates near the generation sites themselves. In the region north of the Sumatra coast, almost 87% of the barotropic energy is converted into baroclinic energy and 23% (0.91 GW) of the converted baroclinic energy is ultimately radiated out from the generation sites. The barotropic‐to‐baroclinic conversion rate over the whole domain is estimated to be ~23 GW, out of which, a major part ~18 GW (80%) dissipates near the generation sites. This reveals that the local dissipation of baroclinic energy dominates in the Andaman Sea.
Barotropic fluid
Internal tide
Energetics
Cite
Citations (33)
Barotropic fluid
Internal tide
Energetics
Energy flux
Tidal power
Cite
Citations (5)
Barotropic fluid
Internal tide
Tidal power
Cite
Citations (90)
Barotropic fluid
Internal flow
Cite
Citations (2)
This thesis deals with the internal tide in the deep ocean, which is generated by the barotropic tide flowing over the bottom topography. The energy flux from the barotropic tide to the internal-wa ...
Barotropic fluid
Internal tide
Energy flux
Cite
Citations (0)
Abstract The Regional Oceanic Modeling System (ROMS) is applied in a nested configuration with realistic forcing to the Southern California Bight (SCB) to analyze the variability in semidiurnal internal wave generation and propagation. The SCB has a complex topography with supercritical slopes that generate linear internal waves at the forcing frequency. The model predicts the observed barotropic and baroclinic tides reasonably well, although the observed baroclinic tides feature slightly larger amplitudes. The strongest semidiurnal barotropic to baroclinic energy conversion occurs on a steep sill slope of the 1900-m-deep Santa Cruz Basin. This causes a forced, near-resonant, semidiurnal Poincaré wave that rotates clockwise in the basin and is of the first mode along the radial, azimuthal, and vertical directions. The associated tidal-mean, depth-integrated energy fluxes and isotherm oscillation amplitudes in the basin reach maximum values of about 5 kW m−1 and 100 m and are strongly modulated by the spring–neap cycle. Most energy is locally dissipated, and only 10% escapes the basin. The baroclinic energy in the remaining basins is orders of magnitudes smaller. High-resolution coastal models are important in locating overlooked mixing hotspots such as the Santa Cruz Basin. These mixing hotspots may be important for ocean mixing and the overturning circulation.
Barotropic fluid
Internal tide
Forcing (mathematics)
Sill
Cite
Citations (57)
Barotropic and baroclinic tides were simulated for the Indonesia Seas using a primitive equation, terrain‐following coordinate model, the Regional Ocean Model System (ROMS) with four tidal constituents (M 2 , S 2 , K 1 , and O 1 ). The region's intricate topography as well as interactions between the Pacific and Indian Ocean tides within the Indonesian Seas resulted in complex barotropic and baroclinic tidal fields. The semidiurnal tides entered from both the Pacific and Indian oceans converging in Makassar Strait and the Ceram Sea with an amphidromic point forming in the Timor Sea. Diurnal tides were dominated by the Pacific Ocean tide. The model successfully replicated the observed tidal elevation fields as determined from TOPEX/POSEIDON crossovers with better performance for the semidiurnal constituents, RMS differences of 4–6 cm, than the diurnal constituents, RMS differences of 7–10 cm. A baroclinic response was apparent in the elevations, and the locations of the observed baroclinic elevation response in TOPEX/POSEIDON data agreed with that of the model. Velocities were baroclinic for all constituents with high spatial variability, particularly near sills and in straits. Extensive interactions occurred in the internal tidal fields: between a beam and its own reflections, between internal tides generated at different locations (i.e., different sides of a channel, or beams generated nearby), and between the barotropic and baroclinic tidal beams. Owing to propagation, even regions >100 km from sills showed significant vertical and horizontal variability resulting from internal tides. This resulted in extremely complex internal tidal fields with high variability, both spatially and temporally during a tidal cycle.
Barotropic fluid
Sill
Internal tide
Cite
Citations (46)
Travel times of reciprocal 1000-km range acoustic transmissions, determined from the 1987 Reciprocal Tomography Experiment, are used to study barotropic tidal currents and a large-scale, coherent baroclinic tide in the central North Pacific Ocean. The difference in reciprocal travel times determines the tidal currents, while the sum of reciprocal travel times determines the baroclinic tide displacement of isotachs (or equivalently, isotherms). The barotropic tidal current accounts for 90% of the observed differential travel time variance. The measured harmonic constants of the eight major tidal constituents of the barotropic tide and the constants determined from current meter measurements agree well with the empirical–numerical tidal models of Schwiderski and Cartwright et al. The amplitudes and phases of the first-mode baroclinic tide determined from sum travel times agree with those determined from moored thermistors and current meters. The baroclinic tidal signals are consistent with a large-scale, phase-locked internal tide, which apparently has propagated northward over 2000 km from the Hawaiian Ridge. The amplitude, phase, and polarization of the first-mode M2 baroclinic tidal displacement and current are consistent with a northward propagating internal tide. The ratio of baroclinic energy to barotropic energy determined using the range-averaging acoustic transmissions is about 8%, while a ratio of 26% was determined from the point measurements. The large-scale, internal tide energy flux, presumed northward, is estimated to be about 180 W m−1.
Barotropic fluid
Internal tide
Cite
Citations (187)
Internal M2 tides near Hawaii are investigated with a two-dimensional, two-layer numerical model. It is seen that along the Hawaiian Ridge barotropic tidal energy is transformed into baroclinic internal tides that propagate in both northeast and southwest directions, as previously hypothesized. The internal tide for a certain beam is seen to propagate well over 1000 km. with an approximate decay scale of 1000 km. An asymmetric pattern in the baroclinic energy flux is observed to the north and south of the Hawaiian Ridge due to the spatially inhomogeneous baroclinic energy sources. The surface manifestation of the M2 internal tide in the model is compared with analysis results from TOPEX/Poseidon satellite altimetry. The baroclinic short-wave variation of a few centimeters amplitude, superposed on the barotropic surface amplitude, agrees well with the altimeter analyses. This, together with snapshots of the interfacial disturbance, allows the authors to sketch the propagation pattern of internal waves emanating northward and southward from the Hawaiian Ridge. Tidal current ellipses in the upper layer are dominated by the baroclinic internal tide with large spatial variability in their magnitude compared to the barotropic tidal ellipses. The M2 baroclinic energy flux is over 10 kW m−1 for the strongest energy beam propagating toward the northeast. Along the western Hawaiian Ridge about 3.8 GW of tidal power is converted from barotropic to baroclinic motion. The average northward or southward flux density for the first baroclinic mode is about 1.35 kW m−1 in the western Hawaiian Ridge. Also, if 2.7 kW m−1 (1.35 kW m−1 to each direction) is assumed for the whole 2000-km-long Hawaiian Ridge, a total of 5.4 GW is obtained. This value indicates that there is still a large uncertainty in the rate of barotropic to radiating baroclinic energy conversion along the Hawaiian Ridge.
Barotropic fluid
Internal tide
Tidal power
Energy flux
Cite
Citations (42)