Abstract Turbulent mixing in the ocean is key to regulate transport of heat, freshwater and biogeochemical tracers, with strong implications for Earth’s climate. In deep ocean, tides supply much mechanical energy required sustain via generation internal waves, known as tides, whose fate—the relative importance their local versus remote breaking into turbulence—remains uncertain. Here, we combine a semi-analytical model tide satellite situ measurements show that from an energetic viewpoint,...

Abstract Vertical mixing is often regarded as the Achilles' heel of ocean models. In particular, few models include a comprehensive and energy‐constrained parameterization by internal tides. Here, we present an energy‐conserving scheme which accounts for local breaking high‐mode tides distant dissipation low‐mode The relies on four static two‐dimensional maps tide dissipation, constructed using mode‐by‐mode Lagrangian tracking energy beams from sources to sinks. Each map associated with...

Internal tides power much of the observed small-scale turbulence in ocean interior. To represent mixing induced by this climate models, cascade internal tide energy to dissipation scales must be understood and mapped. Here, we present a framework for estimating geography sinks. The mapping relies on following ingredients: (i) global observational climatology stratification; (ii) maps generation M2, S2 K1 decomposed into vertical normal modes; (iii) simplified representations low-mode due...

Abstract At suboxic oxygen concentrations, key biogeochemical cycles change and denitrification becomes the dominant remineralization pathway. Earth system models predict loss across most ocean basins in next century; minimum zones near suboxia may become therefore denitrifying. Using an glider survey historical data, we show Gulf of Oman (from 6–12 to <2 μmol kg −1 ) not represented climatologies. Because nonlinearity between concentration, resolutions current are too coarse accurately...

The effects of horizontal resolution and wave drag damping on the semidiurnal M2 tidal energetics are studied for two realistically-forced global HYbrid Coordinate Ocean Model (HYCOM) simulations with 41 layers resolutions 8 km (1∕12.5∘; H12) 4 (1∕25∘; H25). In both simulations, surface error is minimized by tuning strength linear drag, which a parameterization surface-tide energy conversion to unresolved baroclinic modes. tide TPXO8-atlas, an altimetry constrained model, 2.6 cm. Compared...

Abstract The Persian Gulf feeds a warm and salty outflow in the of Oman (northern Arabian Sea). salt climatological distribution is relatively smooth Oman, signature slope current carrying waters difficult to distinguish hundreds kilometers past Strait Hormuz, contrast other outflows world ocean. This study focuses on mechanisms involved spreading Water (PGW) using regional primitive equation numerical simulation. authors show that dispersion PGW occurs through regime distinct from, for...

Abstract Diapycnal mixing of nutrients from the thermocline to surface sunlit ocean is thought be relatively weak in world's subtropical gyres as energy inputs winds are generally low. The interaction internal tides with rough topography enhances diapycnal mixing, yet role tidally induced sustaining nutrient supply remains unexplored. During a field campaign North Atlantic gyre, we tested whether tidal interactions enhance nitrate fluxes upper ocean. We measured an order magnitude increase...

Abstract Diapycnal mixing shapes the distribution of climatically important tracers, such as heat and carbon, these are carried by dense water masses in ocean interior. Here, we analyze a suite observation‐based estimates diapycnal to assess its role within Atlantic Meridional Overturning Circulation (AMOC). The rate mass transformation Ocean's interior shows that there is robust buoyancy increase North Deep Water (NADW, neutral density γ n ≃ 27.6–28.15), with circulation 0.5–8 Sv between...

Abstract The Great Whirl (GW) is a persistent anticyclonic mesoscale eddy that observed seasonally in the Arabian Sea during period embedding 3 months of southwest monsoon (June–July–August) at quasi‐steady location. Its dynamics remain unclear despite it being one largest coherent vortices world ocean. Realistic regional numerical experiments using ROMS are performed to investigate life cycle GW, which not well resolved by sparse available situ measurements region. Using set sensitivity and...

Abstract The processes leading to the depletion of oceanic mesoscale kinetic energy (KE) and energization near‐inertial internal waves are investigated using a suite realistically forced regional ocean simulations. By carefully modifying forcing fields we show that solutions where have ∼ less KE compared with they not. We apply coarse‐graining method quantify fluxes across time scales demonstrate decrease in is associated an wave‐induced reduction inverse cascade enhancement forward from...

Abstract An asymmetry in the clustering of oceanic surface material has been observed at submesoscales. Energetic and ephemeral submesoscale cyclonic fronts are associated with convergence zones, hence cluster material. Their anticyclonic counterparts do not feature such an effect. Yet, mesoscale, literature contradictory about asymmetry. Here, we combine drifter trajectories altimetry‐derived mesoscale eddy database North Atlantic to show that cyclones contain 24% more drifters than...

Abstract. New Caledonia, in the southwestern tropical Pacific, has recently been identified as a hot spot for energetic semidiurnal internal tides. In companion paper, life cycle of coherent tides, characterized by fixed amplitude and phase, was investigated regions through harmonic analysis year-long, hourly time series from numerical simulation output. this study, we investigate temporal variability tide decomposing signals into incoherent components. We show that departure coherence, both...

Hydrothermal vents are oceanic sources of biogeochemical constituents. Some these constituents, such as iron, significantly contribute to global cycles. Yet, their fate, i.e., transport and mixing through physical processes, modification concentration bio-geochemical remains poorly quantified. Using state-of-the-art physical-biogeochemical (CROCO-PISCES) model simulations that resolve submesoscale internal gravity waves parameterized we analyse the processes involved in dispersion passive...

Internal tides, internal waves at tidal frequency, represent a considerable reservoir of kinetic energy within the broad spectrum motions frequencies higher than inertial frequency f. Further, they are argued to play an important role in modulation pathways, such as redistribution toward smaller scales, promoting transfer via forward cascade.New Caledonia, archipelago southwestern tropical Pacific, has recently been identified hot spot for semidiurnal tides based on regional numerical...

Due to their elevation above the sea floor, seamounts are unique underwater structures. An important number of these structures can be found in Pacific and may have a key role ocean. They host variety energetic flow-topography interactions, which lead strong levels turbulent transport mixing. These believed shape, or at least strongly impact, benthic communities. Seamounts feature diverse environmental conditions faunal communities some been qualified as hotspots diversity biomass, they...

New Caledonia, an archipelago in the Coral Sea southwestern tropical Pacific, is internationally recognized for its marine biodiversity including coral reef systems and lagoons (UNESCO World Heritage Site). Yet, only 10 % of Marine Park currently under full protection by restricting human economic activities. Further conservation efforts have failed inter alia linked to political conflicts interest scientific knowledge gaps local ecosystem. Continuous reserves ecologically important...

Abstract. The Arabian Sea and of Oman circulation water masses, subject to monsoon forcing, reveal a strong seasonal variability intense mesoscale features. We describe analyze this these features, using both meteorological data (from ECMWF reanalyses), in situ observations the ARGO float program GDEM – Generalized Digital Environmental mode climatology), satellite altimetry AVISO) regional simulation with primitive equation model (HYCOM Hybrid Coordinate Ocean Model). display comparable...

Abstract The life cycle of semidiurnal internal tides over the Mid-Atlantic Ridge (MAR) sector south Azores is investigated using in situ, a high-resolution mooring and microstructure profiler, satellite data, combination with theoretical model barotropic-to-baroclinic tidal energy conversion. analysis reveals that tide horizontal flux dominated by mode 1 density more distributed among modes 1–10. Most are compatible an interpretation terms standing tides, suggesting they result from...

Abstract There have been recent advancements in the quantification of parameters describing proportion internal tide energy being dissipated locally and “efficiency” diapycnal mixing, that is, ratio mixing rate to kinetic dissipation rate. We show oceanic tidal is nontrivially sensitive covariation these parameters. Varying one at a time can lead significant errors patterns mixing‐driven upwelling downwelling over under estimation such way net globally integrated deep circulation appears...

Abstract Future changes in subduction are suspected to be critical for the ocean deoxygenation predicted by climate models over 21st century. However, drivers of global oxygen have not been fully described or quantified. Here, we address physical mechanisms responsible transport across late‐winter mixed layer base and their relation with water mass formation. Up 70% uptake takes place during Mode Water mostly Southern Ocean North Atlantic. Te driving (i) combination strong currents large...

Abstract The Galápagos archipelago, rising from the eastern equatorial Pacific Ocean some 900 km off South American mainland, hosts an iconic and globally significant biological hotspot. islands are renowned for their unique wealth of endemic species, which inspired Charles Darwin’s theory evolution today underpins one largest UNESCO World Heritage Sites Marine Reserves on Earth. regional ecosystem is sustained by strongly seasonal oceanic upwelling events—upward surges cool, nutrient-rich...

Abstract The propagation characteristics of near‐inertial waves (NIWs) and how mesoscale submesoscale processes affect the waves' vertical penetration are investigated using observations from a mooring array located in northeast Atlantic. year‐long show that motions mainly generated by local wind forcing, they radiate equatorward downward following several strong events (wind stress ≳0.5 N m −2 ). Observational estimates horizontal group speed typically exceed those two orders magnitude,...

Abstract A 4-month glider mission was analyzed to assess turbulent dissipation in an anticyclonic eddy at the western boundary of subtropical North Atlantic. The (radius ≈ 60 km) had a core low potential vorticity between 100 and 450 m, with maximum radial velocities 0.5 m s −1 Rossby number −0.1. Turbulent inferred from vertical water derived flight model. Dissipation suppressed ( ε 5 × 10 −10 W kg ) enhanced below it (>10 −9 ). Elevated coincident quasiperiodic structures velocity...