Impact of currents on surface flux computations and their feedback on dynamics at regional scales
Summary: The paper studies the impact of the use of relative winds (i.e., winds minus ocean currents) to compute heat and momentum fluxes at sea surface. This was done in an area interested by mesoscale eddies and a local boundary current. Impact is relevant both for heat and momentum fluxes. Major differences can be observed in areas with large mesoscale activity. Results suggest that surface currents component in fluxes computation should not be neglected even at such scales and latitudes.
Ocean Sci., 11, 657-666, doi:10.5194/os-11-657-2015, 2015
Simulation of tsunami generation, propagation and coastal inundation in the Eastern Mediterranean
Summary: An advanced tsunami generation, propagation and coastal inundation model is applied to simulate representative earthquake-induced tsunami scenarios in the Eastern Mediterranean. Two areas of interest were selected after evaluating tsunamigenic zones and possible sources in the region: one at the SE of Crete (Greece) and one at the E of Sicily (Italy). Results are indicative of the model’s capabilities, as well of how areas in the Eastern Mediterranean would be affected by eventual larger events.
Ocean Sci., 11, 643-655, doi:10.5194/os-11-643-2015, 2015
Eddy surface properties and propagation at Southern Hemisphere western boundary current systems
Summary: Oceanic eddies are closed circulation features that transport water between regions, taking part in the ocean's heat and salt balance. We perform a comparative eddy census in the East Australian, Agulhas and Brazil currents. We find that eddy propagation in all systems is steered by the local mean flow and bathymetry. Also, eddies present a geographic segregation according to size. Investigating eddy propagation helps us to better understand their effect in local mixing.
Ocean Sci., 11, 629-641, doi:10.5194/os-11-629-2015, 2015
Sea level trend and variability around Peninsular Malaysia
Ocean Sci., 11, 617-628, doi:10.5194/os-11-617-2015, 2015
Accelerated sea level rise and Florida Current transport
Summary: Changes in mass transport of the Florida Current induce significant coastal sea level changes along the Florida Straits and middle Atlantic coast of North America. Analysis of Florida Current transport data finds a decrease in mean transport over the last decade. This decrease coincides with a decrease in AMOC and acceleration of coastal sea levels along the Florida Straits.
Ocean Sci., 11, 607-615, doi:10.5194/os-11-607-2015, 2015
Exploring the isopycnal mixing and helium–heat paradoxes in a suite of Earth system models
Summary: Many ocean circulation models use representations of lateral mixing based on instability theories that predict weak mixing in the ocean interior, much lower than observed. We show that using more realistic mixing improves the distribution of mantle helium-3. It does not, however, resolve the paradox that models reproduce the relationship between mantle helium and radiocarbon with a flux of helium-3 lower than is consistent with the heat leaving the mantle.
Ocean Sci., 11, 591-605, doi:10.5194/os-11-591-2015, 2015
Constraining parameters in marine pelagic ecosystem models – is it actually feasible with typical observations of standing stocks?
Summary: Marine biogeochemical ocean models are embedded into earth system models - which are, to an increasing degree, applied to project the fate of our warming world. These biogeochemical models generally depend on poorly constrained model parameters. In this study we investigate the the demands on observations for an objective estimation of such parameters. A major result is that even modest noise (10%) inherent to observations can hinder the assignment of reasonable parameters.
Ocean Sci., 11, 573-590, doi:10.5194/os-11-573-2015, 2015
Reconstructing bottom water temperatures from measurements of temperature and thermal diffusivity in marine sediments
Summary: Temperature fields in marine sediments are controlled by the geothermal steady state heat flow and the bottom water temperature. Thus, the current sediments' temperature field stores the history of bottom water temperature variation. The aim of this work is the inverse modeling of the bottom water temperature variation in the last year from instantaneous measurements of the depth-dependent temperature and the thermal diffusivity.
Ocean Sci., 11, 559-571, doi:10.5194/os-11-559-2015, 2015
Investigation of suitable sites for wave energy converters around Sicily (Italy)
Summary: The paper describes the analysis of wave energy along the coast of Sicily (Italy). A third-generation model was adopted to reconstruct the wave data along the coast over a period of 14 years. The analysis of the wave energy allowed characterising the most energetic zones and to individuate eight hotspots suitable for the implementation of wave energy converter farms.
Ocean Sci., 11, 543-557, doi:10.5194/os-11-543-2015, 2015
The OceanFlux Greenhouse Gases methodology for deriving a sea surface climatology of CO2 fugacity in support of air–sea gas flux studies
Summary: We describe the OceanFlux Greenhouse Gases methodology for creating an ocean surface CO2 climatology. In situ measurements valid for instantaneous sea surface temperature (SST) were recomputed using a more consistent and averaged SST. The results were normalised to year 2010, averaged by month, and interpolated onto a global 1°×1° grid. The 12 monthly distributions of ocean surface CO2 (see supplement) can be used in air-sea gas flux calculations together with climatologies of other variables.
Ocean Sci., 11, 519-541, doi:10.5194/os-11-519-2015, 2015
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