Abstract The authors examine the turbulent properties of a baroclinically unstable oceanic flow using primitive equation (PE) simulations with high resolution (in both horizontal and vertical directions). Resulting dynamics in surface layers involve large Rossby numbers significant vortical asymmetries. Furthermore, ageostrophic divergent motions associated small-scale frontogenesis are shown to significantly alter nonlinear transfers kinetic energy consequently time evolution dynamics. Such...

Abstract Ocean eddies (with a size of 100–300 km), ubiquitous in satellite observations, are known to represent about 80% the total ocean kinetic energy. Recent studies have pointed out unexpected role smaller oceanic structures 1–50 km scales) generating and sustaining these eddies. The interpretation proposed so far invokes internal instability resulting from large-scale interaction between upper interior layers. Here we show, using new high-resolution simulation realistic North Pacific...

Abstract Low-frequency variability of the Kuroshio Extension (KE) is studied using observations and a multidecadal (1950–2003) hindcast by high-resolution (0.1°), eddy-resolving, global ocean general circulation model for Earth Simulator (OFES). In both OFES satellite altimeter observations, low-frequency sea surface height (SSH) in North Pacific high near KE front. An empirical orthogonal function (EOF) analysis indicates that much SSH western east Japan explained two modes with meridional...

Multiple zonal jets with the east‐west velocity direction alternating latitude are discovered in satellite altimetry data. The time‐varying shown to populate every part of world ocean and its marginal seas best seen anomaly geostrophic vorticity. At midlatitudes have a meridional wavelength about 300 kms r.m.s. sea level, vorticity values 2.4 cm, 6.9 cm/s 1.5 · 10 −6 s −1 , correspondingly. Realistic data from high‐resolution OGCM run on Earth Simulator used justify high vertical coherence...

Analysis of surface flux data suggests that the South China Sea throughflow is a conveyor belt transferring up to 0.2 PW (1 = 1 × 10 15 W) heat and 0.1 Sv 6 m 3 s −1 ) freshwater from into Indonesian maritime continent. As fluxes display substantially different temporal variations with throughflow, we hypothesize acts as capacitor, storing in certain years releasing it others. Results high‐resolution general circulation model confirm this hypothesis, implying likely play more active role...

Abstract Located at the center of western North Pacific Subtropical Gyre, Countercurrent (STCC) is not only abundant in mesoscale eddies, but also exhibits prominent submesoscale eddy features. Output from a ° high-resolution OGCM simulation and gridded satellite altimetry product are analyzed to contrast seasonal STCC variability versus ranges. Resolving scales >150 km, reveals that kinetic energy rms vorticity have maximum May April, respectively, weak positive skewness without...

Abstract Through analysis of a hindcast integration an eddy-resolving quasi-global ocean general circulation model, decadal variability in the Kuroshio–Oyashio Extension region is investigated, with particular emphasis on that subarctic (Oyashio) and Kuroshio (KE) fronts. The KE front deep accompanied by sharp sea surface height (SSH) gradient modest temperature (SST) gradient. In contrast, shallow recognized as zone tight SST but not SSH. As decadal-scale change from warm period around 1970...

XBT and float data of the World Ocean Database 2005 are used to validate new stationary jet‐like features (striations) recently found in high‐resolution mean dynamic ocean topography (MDOT). Two study areas were selected eastern parts North South Pacific subtropical gyres free any strong currents. Appropriate horizontal high‐pass filtering applied ensemble‐mean temperature at 100 m depth revealed striation signal coherent with MDOT. The also distinct 12°C isotherm lying close thermocline....

Using results from a high‐resolution ocean general circulation model, this study identifies the impact of dynamics on mean seasonal cycle sea surface temperature (SST) in southeastern tropical Indian Ocean. An important question about mechanisms regional SST variation arises quick look at satellite‐observed and color. Although color indicates distinctive upwelling season July to September, depression off Java Sumatra is small, forming sharp contrast with other eastern boundary regions. The...

The spatial and temporal properties of zonally coherent jet‐like structures found in high resolution ocean models is examined. We focus on the Pacific Ocean. find jets are not very sensitive to model configuration. Distinct differences persistence vertical structure poleward 30°N S compared with those tropics. make a quantitative comparison between meridional scale Rhines scale. local scaling applies that horizontal variation consistent variations

Intraseasonal sea surface height (SSH) variability and associated eddy energy in the South China Sea is studied using satellite observations an eddy‐resolving, global ocean general circulation model. In both model hindcast observations, a conspicuous minimum of intraseasonal SSH variance found along continental break between shallow shelf deep basin. Specifically strong (ISV) exists following regions: on northern shelf, Gulf Thailand, two bands basin with band located west Luzon Strait...

A surface Quasi‐Geostrophy based (eSQG) method to diagnose the vertical velocity field from Sea Surface Height (SSH) is assessed using high resolution simulations. These simulations concern a turbulent eddy with large Rossby numbers and energetic wind‐driven motions. Results indicate that low‐frequency velocities (and also horizontal motions) can be reconstructed within range of scales between 20 km 400 down 500 m. The only information needed single high‐resolution SSH snapshot on...

Abstract Formation processes responsible for the North Equatorial Undercurrent (NEUC) jets that appear across tropical Pacific Ocean near 9°, 13°, and 18°N are explored both theoretically using numerical models with different complexities. Analyses of an eddy-resolving global ocean general circulation model output reveal NEUC have a mode-1 baroclinic vertical structure spatially persistent on interannual longer time scales. This OGCM-simulated prompts authors to adopt simpler, nonlinear...

Abstract Following recent studies based on altimetric data, this paper analyses the spectral characteristics of sea surface height (SSH) using a new realistic simulation North Pacific Ocean with high resolution ( in horizontal and 100 vertical levels). This resolves smaller scales (down to ≈10 km) than data (limited 70 km because noise level). In eddy kinetic energy (EKE) regions (as western part), SSH slope almost follows k−4 (with k wavenumber) or slightly steeper law agreement altimeter...

Abstract Mesoscale eddy effects on the subduction of North Pacific mode waters are investigated by comparing observations and ocean general circulation models where eddies either parameterized or resolved. The eddy‐resolving produce results closer to than noneddy‐resolving model. There large discrepancies in patterns between models. In model, a given isopycnal is limited cross point mixed layer depth (MLD) front outcrop line whereas observations, takes place broader, zonally elongated band...

Abstract Utilizing the framework of effective surface quasigeostrophic (eSQG) theory, this study explores potential reconstructing 3D upper-ocean circulation structures, including balanced vertical velocity w field, from high-resolution sea height (SSH) data planned Surface Water and Ocean Topography (SWOT) satellite mission. Specifically, authors utilize 1/30°, submesoscale-resolving, OFES model output subject it to SWOT simulator that generates along-swath SSH with expected measurement...

Abstract Although both geostrophic‐balanced mesoscale eddies and unbalanced small‐scale processes have been well studied in the northeastern South China Sea (NE‐SCS), less attention has devoted to submesoscales between (i.e., O (1–10 km)), which is recognized as an important conduit connecting balanced motions. Based on output from a 1/30° OGCM simulation, spatiotemporal characteristics generation mechanisms of NE‐SCS are investigated this study. Through examining submesoscale relative...

Abstract Kim, H., Kimura, S., Shinoda, A., Kitagawa, T., Sasai, Y., and Sasaki, H. 2007. Effect of El Niño on migration larval transport the Japanese eel (Anguilla japonica). – ICES Journal Marine Science, 64: –. To clarify effect an eels japonica) in western North Pacific, differences patterns larvae (leptocephali) non-El years were compared qualitatively through a numerical particle-tracking model. Depending interannual meridional displacements salinity front bifurcation Equatorial...

It is reported that turbulent mixing enhanced in the South China Sea (SCS), and it highly variable both space time. Generation breaking of internal tides has been identified as main process to drive SCS, while contributions from other processes are not clear enough. Here we investigate potential contribution mesoscale eddies SCS using a high resolution numerical simulation. Our results show effectively dissipate over complex rough topography indicate generation submesoscale motions lee waves...

As the North Equatorial Current (NEC)–bifurcation is known to be related El Niño‐Southern Oscillation (ENSO) events, influence of position NEC bifurcation on transport success larval Japanese eel Anguilla japonica was investigated. Using a Lagrangian modelling approach, simulated and relative Niño La Niña events NEC‐bifurcation particle analysed. The number particles transported from Kuroshio tended lowest during years, differences between regular years were small. observed in simulations...