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
Argo data assimilation into HYCOM with an EnOI method in the Atlantic Ocean
Ocean Sci., 11, 195-213, doi:10.5194/os-11-195-2015, 2015
Roles of initial ocean surface and subsurface states on successfully predicting 2006–2007 El Niño with an intermediate coupled model
Ocean Sci., 11, 187-194, doi:10.5194/os-11-187-2015, 2015
A wind-driven nonseasonal barotropic fluctuation of the Canadian inland seas
Summary: A wind-driven, spatially coherent mode of nonseasonal depth-independent variability in the Canadian inland seas is identified based on observational measurements and a numerical model over 2003--2013. This dominant mode of nonseasonal variability is partly related to the North Atlantic Oscillation. The mode is associated with net flows into and out of the Canadian inland seas as well as internal mass redistribution within the Canadian inland seas.
Ocean Sci., 11, 175-185, doi:10.5194/os-11-175-2015, 2015
Coastal sea level response to the tropical cyclonic forcing in the northern Indian Ocean
Summary: This study examines the observed storm-generated sea-level variations at several Indian coastal locations in the Arabian Sea and the Bay of Bengal and identifies them as storm surges and harbour oscillations. The residual sea levels measured from sea-level stations in AS have been identified as Kelvin-type surges propagating northwards with almost constant amplitude. Multilinear regression analysis using local surface meteorological data is able to account for ~63% of daily mean sea level.
Ocean Sci., 11, 159-173, doi:10.5194/os-11-159-2015, 2015
Using empirical orthogonal functions derived from remote-sensing reflectance for the prediction of phytoplankton pigment concentrations
Summary: We have developed a method to assess pigment concentrations from continuous optical measurements by applying an empirical orthogonal function analysis to remote-sensing reflectance data derived from hyperspectral ship-based and multispectral satellite measurements in the Atlantic Ocean. The method allows for the derivation of time series from continuous reflectance data of various pigment groups at various regions, which can be used to study phytoplankton composition and photophysiology.
Ocean Sci., 11, 139-158, doi:10.5194/os-11-139-2015, 2015
Measuring air–sea gas-exchange velocities in a large-scale annular wind–wave tank
Summary: Our article presents successful gas exchange measurements obtained in a large-scale wind-wave tank. The adopted box model methodology, experimental produce and instrumentation are described in detail. For the first time, parallel measurements of total transfer velocities for 14 individual gases within a wide range of solubility have been achieved. Various wind speed conditions and the effect of surfactant layers have been investigated providing exciting results.
Ocean Sci., 11, 121-138, doi:10.5194/os-11-121-2015, 2015
Comparative heat and gas exchange measurements in the Heidelberg Aeolotron, a large annular wind-wave tank
Summary: A comparative study of simultaneous heat and gas exchange measurements was performed in the large annular Heidelberg Air-Sea Interaction Facility, the Aeolotron, under homogeneous water surface conditions, including the measurement of the Schmidt number exponent. Provided the Schmidt number exponent is known and that the heated patch is large enough to reach the thermal equilibrium, it is possible to scale heat transfer velocities measured by active thermography to gas transfer velocities.
Ocean Sci., 11, 111-120, doi:10.5194/os-11-111-2015, 2015