Interannual variation of settling particles reflects upper‐ocean circulation in the southern Chukchi Borderland, 2010‐2014

Abstract. The SEMAPHORE (Structure des Echanges Mer-Atmosphère, Propriétés des Hétérogénéités Océaniques: Recherche Expérimentale) experiment has been conducted from June to November 1993 in the Northeast Atlantic between the Azores and Madeira. It was centered on the study of the mesoscale ocean circulation and air-sea interactions. The experimental investigation was achieved at the mesoscale using moorings, floats, and ship hydrological survey, and at a smaller scale by one dedicated ship, two instrumented aircraft, and surface drifting buoys, for one and a half month in October-November (IOP: intense observing period). Observations from meteorological operational satellites as well as spaceborne microwave sensors were used in complement. The main studies undertaken concern the mesoscale ocean, the upper ocean, the atmospheric boundary layer, and the sea surface, and first results are presented for the various topics. From data analysis and model simulations, the main characteristics of the ocean circulation were deduced, showing the close relationship between the Azores front meander and the occurrence of Mediterranean water lenses (meddies), and the shift between the Azores current frontal signature at the surface and within the thermocline. Using drifting buoys and ship data in the upper ocean, the gap between the scales of the atmospheric forcing and the oceanic variability was made evident. A 2 °C decrease and a 40-m deepening of the mixed layer were measured within the IOP, associated with a heating loss of about 100 W m-2. This evolution was shown to be strongly connected to the occurrence of storms at the beginning and the end of October. Above the surface, turbulent measurements from ship and aircraft were analyzed across the surface thermal front, showing a 30% difference in heat fluxes between both sides during a 4-day period, and the respective contributions of the wind and the surface temperature were evaluated. The classical momentum flux bulk parameterization was found to fail in low wind and unstable conditions. Finally, the sea surface was investigated using airborne and satellite radars and wave buoys. A wave model, operationally used, was found to get better results compared with radar and wave-buoy measurements, when initialized using an improved wind field, obtained by assimilating satellite and buoy wind data in a meteorological model. A detailed analysis of a 2-day period showed that the swell component, propagating from a far source area, is underestimated in the wave model. A data base has been created, containing all experimental measurements. It will allow us to pursue the interpretation of observations and to test model simulations in the ocean, at the surface and in the atmospheric boundary layer, and to investigate the ocean-atmosphere coupling at the local and mesoscales.

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Simulating the upper ocean circulation on the belize shelf: An application of a triply nested-grid ocean circulation model

Journal of Ocean University of China ◽

10.1007/s11802-005-0052-0 ◽

2005 ◽

Vol 4 (4) ◽

pp. 315-328 ◽

Cited By ~ 2

Author(s):

Jinyu Sheng ◽

Liqun Tang ◽

Liang Wang

Keyword(s):

Ocean Circulation ◽

Circulation Model ◽

Upper Ocean ◽

Ocean Circulation Model ◽

Nested Grid

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Marginal Sea Overflows and the Upper Ocean Interaction

Journal of Physical Oceanography ◽

10.1175/2008jpo3934.1 ◽

2009 ◽

Vol 39 (2) ◽

pp. 387-403 ◽

Cited By ~ 13

Author(s):

Shinichiro Kida ◽

Jiayan Yang ◽

James F. Price

Keyword(s):

Ocean Circulation ◽

Potential Vorticity ◽

Baroclinic Instability ◽

Upper Ocean ◽

Marginal Sea ◽

The Mediterranean ◽

The Difference ◽

Set Up ◽

Numerical Model Experiments ◽

Gyre Circulation

Abstract Marginal sea overflows and the overlying upper ocean are coupled in the vertical by two distinct mechanisms—by an interfacial mass flux from the upper ocean to the overflow layer that accompanies entrainment and by a divergent eddy flux associated with baroclinic instability. Because both mechanisms tend to be localized in space, the resulting upper ocean circulation can be characterized as a β plume for which the relevant background potential vorticity is set by the slope of the topography, that is, a topographic β plume. The entrainment-driven topographic β plume consists of a single gyre that is aligned along isobaths. The circulation is cyclonic within the upper ocean (water columns are stretched). The transport within one branch of the topographic β plume may exceed the entrainment flux by a factor of 2 or more. Overflows are likely to be baroclinically unstable, especially near the strait. This creates eddy variability in both the upper ocean and overflow layers and a flux of momentum and energy in the vertical. In the time mean, the eddies accompanying baroclinic instability set up a double-gyre circulation in the upper ocean, an eddy-driven topographic β plume. In regions where baroclinic instability is growing, the momentum flux from the overflow into the upper ocean acts as a drag on the overflow and causes the overflow to descend the slope at a steeper angle than what would arise from bottom friction alone. Numerical model experiments suggest that the Faroe Bank Channel overflow should be the most prominent example of an eddy-driven topographic β plume and that the resulting upper-layer transport should be comparable to that of the overflow. The overflow-layer eddies that accompany baroclinic instability are analogous to those observed in moored array data. In contrast, the upper layer of the Mediterranean overflow is likely to be dominated more by an entrainment-driven topographic β plume. The difference arises because entrainment occurs at a much shallower location for the Mediterranean case and the background potential vorticity gradient of the upper ocean is much larger.

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Abstract: Jurassic to Quaternary Upper Ocean Circulation and Petroleum Source Rock Formation in the Atlantic

AAPG Bulletin ◽

10.1306/e4fd43eb-1732-11d7-8645000102c1865d ◽

1999 ◽

Vol 83 ◽

Author(s):

HANDOH, ITSUKI C.

Keyword(s):

Source Rock ◽

Ocean Circulation ◽

Upper Ocean ◽

Rock Formation ◽

Petroleum Source Rock

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Sensitivity of modelled North Sea cod larvae transport to vertical behaviour, ocean model resolution and interannual variation in ocean dynamics

ICES Journal of Marine Science ◽

10.1093/icesjms/fsy039 ◽

2018 ◽

Vol 75 (7) ◽

pp. 2413-2424 ◽

Cited By ~ 8

Author(s):

Kristina Øie Kvile ◽

Giovanni Romagnoni ◽

Knut-Frode Dagestad ◽

Øystein Langangen ◽

Trond Kristiansen

Keyword(s):

North Sea ◽

Ocean Circulation ◽

Interannual Variation ◽

Model Performance ◽

Vertical Movement ◽

Ocean Model ◽

Population Connectivity ◽

Ocean Dynamics ◽

Model Resolution ◽

Eggs And Larvae

Abstract Transport with ocean currents affects the spatial distribution and survival of fish eggs and larvae and thereby population connectivity. Biophysical models are commonly used to understand these dynamics. Advancements such as implementing vertical swimming behaviour and higher resolution ocean circulation models are known to improve model performance, however, the relative importance of vertical behaviour vs. ocean model resolution is elusive. Here, we use North Sea cod (Gadus morhua) as a case study to assess how vertical movement, ocean model resolution and interannual variation in ocean dynamics influence drift patterns and population connectivity. We couple a fine (1.6 km, 3 h) and coarser (4 km, 24 h) ocean model to an individual-based model for cod eggs and larvae, and compare simulations with and without vertical movement of eggs and larvae. The results are moderately influenced by vertical movement and ocean model resolution but differ substantially between years. While ocean model resolution is consistently more influential than vertical movement, the effect of vertical movement strongly depends on the spatiotemporal scale of the analyses. This study highlights which aspects of biophysical modelling of connectivity that most critically affect the results, allowing better investing computational resources and proposing goal-based guidelines for future studies.

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