Mean circulation in the coastal ocean off northeastern North America from a regional-scale ocean model
Ocean Sci., 11, 503-517, doi:10.5194/os-11-503-2015, 2015
Decadal variability and trends of the Benguela upwelling system as simulated in a high-resolution ocean simulation
Summary: The atmospheric drivers of the Benguela upwelling systems and its variability are statistically analysed with an ocean-only simulation over the last decades. Atmospheric upwelling-favourable conditions are southerly wind/wind stress, a strong subtropical anticyclone, and an ocean-land sea level pressure gradient as well as a negative ENSO and a positive AAO phase. No long-term trends of upwelling and of ocean-minus-land air pressure gradients, as supposed by Bakun, can be seen in our analysis.
Ocean Sci., 11, 483-502, doi:10.5194/os-11-483-2015, 2015
Dynamics of turbulent western-boundary currents at low latitude in a shallow-water model
Ocean Sci., 11, 471-481, doi:10.5194/os-11-471-2015, 2015
Circulation, eddies, oxygen, and nutrient changes in the eastern tropical South Pacific Ocean
Summary: Mean circulation in the eastern tropical South Pacific in 50-600m depth is modified by seasonal variability and eddies on the poleward side of the oxygen minimum zone(OMZ). Floats with parking depth at 400m show westward flow in the equatorial channel, sluggish flow in the northern part of the OMZ, and passage of eddies with oxygen anomalies. Net community production rates were estimated from a float. Oxygen decrease in 50-300m depth since 1976 is related to an increase in nitrate and phosphate.
Ocean Sci., 11, 455-470, doi:10.5194/os-11-455-2015, 2015
Water level oscillations in Monterey Bay and Harbor
Summary: Seiches in coastal bays can produce significant water level oscillations that impact maritime operations and introduce ecological stress. Monterey Bay, California, is found to have wave-driven short-period oscillations that can reinforce themselves, resulting in water level amplification. At longer periods the oscillations are not wave-driven and several potential forcing mechanisms are examined. A gyre offshore the bay is suggested as the driver, while other potential drivers are discounted.
Ocean Sci., 11, 439-453, doi:10.5194/os-11-439-2015, 2015
Assessment of an ensemble system that assimilates Jason-1/Envisat altimeter data in a probabilistic model of the North Atlantic ocean circulation
Summary: A realistic ocean circulation model is adapted to explicitly simulate model uncertainties and an ensemble data assimilation -stochastic perturbations, altimetric data and 4-D observation operator- is developed in order to control the Gulf Stream dynamic. The performance of the ensemble system is measured through probabilistic approach; the update then adjusts the bias and the dispersion of the ensemble (reliability) and reduces the uncertainty by 30% (resolution) for the SSH variable.
Ocean Sci., 11, 425-438, doi:10.5194/os-11-425-2015, 2015
Modelling survival and connectivity of Mnemiopsis leidyi in the south-western North Sea and Scheldt estuaries
Summary: The reproduction, survival, and transport of the comb jelly Mnemiopsis leidyi was studied with three models in the Scheldt estuaries and the southern North Sea. The results suggest that (a) the estuaries can retain an overwintering population and seed offshore populations; (b) M. leidyi can survive in the North Sea, and be transported between coastal inlets; and (c) M. leidyi cannot reproduce well in the North Sea, but this might change with global warming. The models need further improvement.
Ocean Sci., 11, 405-424, doi:10.5194/os-11-405-2015, 2015
Friction and mixing effects on potential vorticity for bottom current crossing a marine strait: an application to the Sicily Channel (central Mediterranean Sea)
Ocean Sci., 11, 391-403, doi:10.5194/os-11-391-2015, 2015
Retrieving the availability of light in the ocean utilising spectral signatures of vibrational Raman scattering in hyper-spectral satellite measurements
Ocean Sci., 11, 373-389, doi:10.5194/os-11-373-2015, 2015
Eddy characteristics in the South Indian Ocean as inferred from surface drifters
Summary: Eddies in the South Indian Ocean (SIO) were statistically investigated based on 2082 surface drifters, and 19252 eddies were identified with 60% anticyclonic eddies. Mesoscale and submesoscale eddies show different spatial distributions. Large eddies mainly appear in regions with large eddy kinetic energy. The submesoscale anticyclonic eddies are densely distributed in the subtropical basin in the central SIO. The number of mesoscale eddies shows statistically significant seasonal variability.
Ocean Sci., 11, 361-371, doi:10.5194/os-11-361-2015, 2015
Deep drivers of mesoscale circulation in the central Rockall Trough
Summary: The Rockall Trough feeds warm salty water to Polar regions and the European Shelf. Detailed observations from an underwater glider show that a) the meandering surface current field in the central trough is driven by deep eddies; b) chance circulations deflect the eastern slope current and warm the western side; c) and altimeter observations omit the mean flow in the narrow slope current. There are wider implications for satellite altimeter observations, ocean monitoring and ocean model results.
Ocean Sci., 11, 343-359, doi:10.5194/os-11-343-2015, 2015
Modelling of the anthropogenic tritium transient and its decay product helium-3 in the Mediterranean Sea using a high-resolution regional model
Summary: The anthropogenic tritium invasion, and its decay product helium-3, was simulated for the first time in the Mediterranean Sea, using a high-resolution regional model (NEMO-MED12). The simulation covers the entire tritium (3H) transient generated by the atmospheric nuclear weapons tests performed in the 1950s and early 1960s and run until 2011. The model correctly simulates the main features of the thermohaline circulation in the Mediterranean Sea, with a realistic time compared to observations.
Ocean Sci., 11, 323-342, doi:10.5194/os-11-323-2015, 2015
Technical Note: A fully automated purge and trap GC-MS system for quantification of volatile organic compound (VOC) fluxes between the ocean and atmosphere
Summary: The oceans are a key source of a number of atmospherically important volatile gases. The accurate and robust determination of trace gases in seawater is a significant analytical challenge. Here we describe a gas chromatograph mass spectrometer based purge and trap system that was developed for the fully automated analysis of dissolved very short-lived species (VSLS) in seawater sampled from a research ship.
Ocean Sci., 11, 313-321, doi:10.5194/os-11-313-2015, 2015
Correlation between subsurface high-salinity water in the northern South China Sea and the North Equatorial Current–Kuroshio circulation system from HYCOM simulations
Summary: Here, we investigated the seasonal variability of subsurface high-salinity water (SHSW) in the northern South China Sea (SCS) and its relationship with the North Equatorial Current-Kuroshio circulation system. Results give new insight into water exchange through the Luzon Strait (LS). The changes in western Pacific large-scale circulation modulate the water exchange in the LS, and thus influence the SHSW in the interior SCS basin.
Ocean Sci., 11, 305-312, doi:10.5194/os-11-305-2015, 2015
Tidal forcing, energetics, and mixing near the Yermak Plateau
Summary: Over the Yermak Plateau northwest of Svalbard there is substantial energy conversion from barotropic to internal tides. Internal tides are trapped along the topography. An approximate local conversion-to-dissipation balance is found over shallows and also in the deep part of the sloping flanks. Dissipation of tidal energy can be a significant contributor to turbulent mixing and cooling of the Atlantic layer in the Arctic Ocean.
Ocean Sci., 11, 287-304, doi:10.5194/os-11-287-2015, 2015
In situ autonomous optical radiometry measurements for satellite ocean color validation in the Western Black Sea
Summary: The accuracy of primary satellite ocean color data products from MODIS on-board Aqua and the VIIRS is investigated using in situ measurements from the ocean color component of the Aerosol Robotic Network (AERONET-OC). Results from the comparison of normalized water-leaving radiance LWN indicate biases of a few percent between satellite-derived and in situ data at the center wavelengths relevant for the determination of chlorophyll-a concentration.
Ocean Sci., 11, 275-286, doi:10.5194/os-11-275-2015, 2015
Technical Note: Watershed strategy for oceanic mesoscale eddy splitting
Summary: This study established a splitting strategy that could separate multinuclear eddies into mononuclear eddies. As the values of eddy parameters (e.g. SLA, geostrophic potential vorticity, Okubo–Weiss parameter) are similar to basins in a map, the natural divisions of the basins are the watersheds between them. It can also be applied to automatic identification of troughs and ridges from weather charts. We denoted it the Universal Splitting Technology for Circulations (USTC) method.
Ocean Sci., 11, 269-273, doi:10.5194/os-11-269-2015, 2015
A geographical and seasonal comparison of nitrogen uptake by phytoplankton in the Southern Ocean
Summary: Phytoplankton contribute to the regulation of the Earth's climate. In this study, we investigated the factors which affect the amount of nitrogen that phytoplankton in the Southern Ocean are able to use for their growth. We collected data during a winter cruise and a summer cruise. We found that in winter, day light and the amount of ammonium (a nitrogenous nutrient) were the two most important factors. In summer, it seems that the influx of nutrients (such as iron) plays a major role.
Ocean Sci., 11, 251-267, doi:10.5194/os-11-251-2015, 2015
Constraining energetic slope currents through assimilation of high-frequency radar observations
Ocean Sci., 11, 237-249, doi:10.5194/os-11-237-2015, 2015
Temperature–salinity distribution in the northeastern Atlantic from ship and Argo vertical casts
Summary: The present study defines new interpolation functions for hydrological data. These functions are applied to generate climatological maps of temperature-salinity distribution with a 25m depth interval and a 30km space interval (MEDTRANS data set). The MEDTRANS climatology gives more details of the distribution of water characteristics in the subtropical northeastern Atlantic than other alternative climatologies and is able to reproduce a number of dynamic features described in the literature.
Ocean Sci., 11, 215-236, doi:10.5194/os-11-215-2015, 2015