Browse Articles

Sea Surface Height Variability in the 30–120 km Wavelength Band From Altimetry Along‐Track Observations

  •  31 March 2021

Key Points

  • The sea surface height (SSH) variability in the 30–120 km wavelength band was derived from altimetry along‐track SSH variance spectra

  • High SSH variability in the 30–120 km wavelength band was found in the intratropics of all oceans and in five regions along the Antarctic Circumpolar Current

  • The average spectral slope in the 30–120 km wavelength band in the intratropics was about −2.14–−1.56, consistent with Garrett‐Munk model

Revisit the Vertical Structure of the Eddies and Eddy‐Induced Transport in the Leeuwin Current System

  •  27 March 2021

Key Points

  • A new method for eddy reconstruction is devised that expresses the eddy interior anomaly as eddy‐induced and background parts

  • Cyclonic (anticyclonic) eddies in the Leeuwin Current system are usually subsurface (surface)‐intensified

  • The horizontal and vertical structure of volume, heat, and salt transport by the Leeuwin Current system eddies are estimated

Satellite‐Observed Decreases in Water Turbidity in the Pearl River Estuary: Potential Linkage With Sea‐Level Rise

  •  27 March 2021

Key Points

  • The water turbidity in the Pearl River Estuary has decreased at a rate of 0.11 NTU per year

  • The decline in water turbidity near the mouth was associated with sea‐level rise in this area

  • Reasons responsible for the decline in water turbidity were complicated

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Issue Information

  •  22 March 2021

Three‐Dimensional Simulation of Shoaling Internal Solitary Waves and Their Influence on Particle Transport in the Southern Red Sea

  •  22 March 2021

Key Points

  • First three dimensional high‐resolution realistic simulation of internal solitary waves (ISWs) shoaling process in the southern Red Sea

  • Simulation results indicate that the ISWs shoaling mechanism in the southern Red Sea follows a “fission” process

  • Particle transport are examined quantitatively, showing significant influence of the ISWs shoaling process on the particles movements

Asymmetric Wave Distributions of Tropical Cyclones Based on CFOSAT Observations

  •  22 March 2021

Key Points

  • China‐France oceanography satellite observed significant asymmetry in the spatial distributions of wave heights during tropical cyclones (TCs)

  • The highest significant wave height is located on the right (left) side of TCs in the Northern (Southern) Hemisphere

  • Asymmetry of wind fields plays an important role in wave distribution, as does the influence from nearby continents

Surf Zone Waves at the Onset of Breaking: 1. LIDAR and IR Data Fusion Methods

  •  22 March 2021

Key Points

  • Fusion of remote sensing data provides new data on wave height, wave celerity, and wave slope metrics for surf zone waves

  • Thermal infrared signatures of spilling and plunging waves are distinct and differentiable

  • Fitting an analytical shape model to measured wave profiles improves wave celerity and shape measurements

Surf Zone Waves at the Onset of Breaking: 2. Predicting Breaking and Breaker Type

  •  22 March 2021

Key Points

  • Critical breaker parameters vary with breaker type and are maximum near the onset of breaking

  • The ratio of wave height to water depth and wave face slope can be used together to predict breaking and breaker type

  • The Miche steepness criteria do not perform well on this depth‐limited breaking data

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Transports and Accumulations of Greenland Sea Intermediate Waters in the Norwegian Sea

  •  20 March 2021

Key Points

  • We examine water masses transported from the Greenland Sea to the Norwegian Sea using hydrographic data collected in 2015

  • A gap in the Mohn Ridge acted as a major passage of intermediate waters when the outflow in the Jan Mayen Channel was temporarily ceased

  • Atlantic‐origin Water becomes an important component of the Greenland Sea intermediate waters to feed the Iceland‐Scotland Overflow Water

Synergy of In Situ and Satellite Ocean Observations in Determining Meridional Heat Transport in the Atlantic Ocean

  •  19 March 2021

Key Points

  • Interannual variations in altimeter‐derived meridional heat transport (MHT) at 26.5°N show good agreement with mooring‐based MHT (r = 0.78)

  • Geostrophic and Ekman transports dominate MHT changes during different time periods

  • MHT is highly correlated with the strength of the meridional overturning circulation in both the North and South Atlantic Ocean

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The role of sand in wave boundary layers over primarily muddy seabeds: Implications for wave‐supported gravity flows

  •  9 April 2021

Key Points

  • Greater sand fraction enhances ripple formation and near‐bed turbulence

  • Sediment‐induced stratification suppresses turbulence in high wave conditions

  • A weakly stratified layer is observed near the bed with a critically stratified layer above

The impact of climate change on ocean submesoscale activity

  •  8 April 2021

Key Points

  • Submesoscale activity is substantially reduced under global warming

  • A scaling for the vertical buoyancy flux based on mixed layer instability overestimates the reduction in the flux under global warming

  • The reduction in mixed depth under global warming is reduced when submescale activity is included

The Effect of Sea Ice on Tidal Propagation in the Kitikmeot Sea, Canadian Arctic Archipelago

  •  8 April 2021

Key Points

  • Tidal height and currents are damped > 50% in winter, likely due to high sea‐ice friction and tidal‐induced sea‐ice blockages upstream.

  • Upon entering the Kitikmeot Sea, the dominant Atlantic‐origin tides dissipate, resulting in relatively low tidal energy.

  • The K1 tidal height is larger than the M2 tidal height in the western Kitikmeot Sea due to tidal resonance.

A 30 Year Time Series of Transient Tracer‐based Estimates of Anthropogenic Carbon in the Central Labrador Sea

  •  8 April 2021

Key Points

  • In regions of ventilation, assuming a constant tracers' saturation in the TTD method results in significant negative bias of Cant estimates.

  • Annual estimates of Cant column inventory between 1986 and 2016 reveal a non‐steady accumulation rate of Cant in Labrador Sea.

  • The temporal variability of the Cant storage in the central Labrador Sea appears to be linked to the strength of convection.

More than skin deep: sea surface temperature as a means of inferring Atlantic Water variability on the southeast Greenland continental shelf near Helheim Glacier

  •  7 April 2021

Key Points

  • Sea surface temperatures measure upper ocean temperatures after variability tied to the atmosphere is removed

  • Once adjusted for air temperature, sea surface temperatures near the fjord reflect deep Atlantic Water temperatures entering Sermilik Fjord

  • Dilution of Atlantic Water as it intrudes onto the continental shelf modulates nearshore temperatures

Structure and Variability of Abyssal Current in Northern South China Sea Based on CPIES Observations

  •  7 April 2021

Key Points

  • The abyssal current in the northern South China Sea flows southwestward along the boundary with an average velocity of about 2.5 cm/s.

  • The abyssal current is strong in the summer/autumn but weak in the spring/winter, and a countercurrent occurs in the autumn in the east.

  • The current is dominated by tides and near‐inertial waves at high frequencies and by a westward‐propagating 70‐day low‐frequency signal.

Brazil Current volume transport variability during 2009‐2015 from a long‐term moored array at 34.5°S

  •  7 April 2021

Key Points

  • The multiyear continuous absolute Brazil Current transport measured at 34.5°S has significant variability on daily to monthly time scales

  • The baroclinic component accounts for the largest part of the absolute transport variance, but the barotropic variance is not negligible

  • No meaningful seasonal cycle, interannual variability or trend is detected during the roughly six years of daily transport measurements

Spatial distribution of dissolved methane over extreme oceanographic gradients in the subtropical eastern South Pacific (17° to 37°S)

  •  4 April 2021

Key Points

  • CH4 spatial distribution of in the subtropical eastern South Pacific shows strong heterogeneity

  • Maxima in CH4 accumulations occur in the mesotrophic area associated with eddies followed by coastal upwelling.

  • The subtropical eastern South Pacific region contributes with 87.9 Gg of CH4 per year towards the atmosphere.

Coherent pathways for subduction from the surface mixed layer at ocean fronts

  •  4 April 2021

Key Points

  • The dynamical pathways of subduction from the surface mixed layer to the pycnocline at a front are characterized using Lagrangian analysis.

  • The pathways of subduction are influenced by mixed layer mesoscale (geostrophic) and submesoscale (ageostrophic) frontogenetic processes.

  • Due to the influence of submesoscale along‐front variability, subduction is coherent on submesoscale, $\sim$ 10∼km, length scales.

Impact of intraseasonal waves on Angolan warm and cold events

  •  4 April 2021

Key points

  • Intraseasonal variability of the Angola Current is linked to equatorial ocean dynamics and interfere with Benguela Niños and Niñas

  • Coastally trapped waves off Angola at 120‐day period are associated with equatorial basin‐mode resonance

  • Intraseasonal coastally trapped waves impact sea surface temperature off Angola and in the Gulf of Guinea via thermocline feedback

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EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates

Key Points

  • EN4 dataset of quality‐controlled temperature and salinity profiles is described
  • Dataset covers 1900 to present and includes monthly objective analyses
  • A novel method is presented to estimate uncertainty in the objective analyses

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Observation of rogue wave holes in a water wave tank

Key Points

  • Experimental generation of rogue wave holes
  • Rogue waves holes within the framework of the nonlinear Schrodinger equation
  • Rogue wave holes modeled by the Peregrine soliton

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A Global Perspective on Microplastics

Key Points

  • The sources, behavior, fate, and effects of microplastics are inexplicably tied to those of their plastic product and macrodebris precursors, as well as the nanoplastics into which they fragment
  • Microplastic sampling and characterization methods are evolving, but their inadequacies still hamper efforts to evaluate the true extent of their presence and consequences in the built and natural environments
  • Microplastics are a global/multimedia phenomenon; hence, they cannot be adequately understood, or related concerns resolved, in the context of the marine environment alone or a single discipline

Open access

Stability of the Atlantic Meridional Overturning Circulation: A Review and Synthesis

Key Points

  • It cannot be ruled out that the current or future AMOC is in a regime of multiple equilibria
  • Determining the proximity of the AMOC to stability thresholds is a main research challenge
  • Further research is needed to identify observable metrics that distinguish between an AMOC slowdown and a collapse

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Understanding Arctic Ocean Circulation: A Review of Ocean Dynamics in a Changing Climate

Key Points

  • Major features of Arctic Ocean circulation are reviewed and interpreted theoretically
  • Fundamental ocean dynamics are set in the context of a changing Arctic climate
  • We describe how Arctic dynamics might change in the future

Plain Language Summary

The Arctic region is experiencing the most rapid environmental changes on Earth, with unparalleled air temperature increases, a warming ocean, and melting permafrost, snow, and ice. The ocean is a central control via Arctic Ocean warming, freshening, and circulation dynamics that link to the sea ice, atmosphere, and terrestrial environment. Given the rapid pace of Arctic change, it is vital to take stock of present understanding of the ocean circulation to address knowledge gaps and make viable future predictions. Present understanding of the principal geophysical fluid dynamics of Arctic Ocean circulation is synthesized here, and we speculate on how the dynamics of the ocean‐ice‐atmosphere system might change in a warming Arctic.

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