Effects of lateral processes on the seasonal water stratification of the Gulf of Finland: 3-D NEMO-based model study
Ocean Sci. Discuss., 12, 2395-2421, doi:10.5194/osd-12-2395-2015, 2015
Continuous seiche in bays and harbors
Summary: Bays and harbors naturally resonate with standing waves also known as seiches. Seiches are usually considered temporary, however we identify small amplitude, continuously present seiches in 6 bays around the Pacific and suggest that tidally--forced shelf--resonances are a primary driver of continuous seiches.
Ocean Sci. Discuss., 12, 2361-2394, doi:10.5194/osd-12-2361-2015, 2015
Volume transport and mixing of the Faroe Bank Channel overflow from one year of moored measurements
Summary: One-year long moored measurements of currents and hydrographic properties in the overflow region of the Faroe Bank Channel have provided a more accurate observational-based estimate of the volume transport, entrainment and eddy diffusivities associated with the overflow plume. The data set resolves the temporal variability and covers the entire lateral and vertical extent of the plume.
Ocean Sci. Discuss., 12, 2315-2359, doi:10.5194/osd-12-2315-2015, 2015
Remote sensing of chlorophyll in the Baltic Sea at basin scale from 1997 to 2012 using merged multisensor data
Summary: To date, there are no studies focusing on the annual cycle of phytoplankton in the Baltic Sea. Available investigations are based on spatially and/or temporally limited datasets. We fill this gap using satellite data. First: using an extensive in-situ database of chlorophyll, we ground truth several satellite algorithms over the entire Baltic area. Second, we provide horizontally-averaged daily chlorophyll estimates divided by areas. Derived climatologies and anomalies are also presented.
Ocean Sci. Discuss., 12, 2283-2313, doi:10.5194/osd-12-2283-2015, 2015
Impact of vertical and horizontal advection on nutrient distribution in the South East Pacific
Summary: Vertical velocity in the ocean makes an important contribution to the modulation of marine ecosystems through its impact on fluxes of nutrients and phytoplankton. Here, we estimate full 3D current velocity fields from an observation-based data product. The 3D currents are used to force a set of particle-tracking (Lagrangian) experiments. The Lagrangian results show that the impact of vertical advection on nutrient redistribution is as high as 30% of the contribution of horizontal advection.
Ocean Sci. Discuss., 12, 2257-2281, doi:10.5194/osd-12-2257-2015, 2015
The dynamic connection of the Indonesian Throughflow, South Indian Ocean Countercurrent and the Leeuwin Current
Summary: In the upper layers of the South Indian Ocean, three anomalous currents are observed: The South Indian Ocean Countercurrent, the Leeuwin Current and the Indonesian Throughflow. Using two models of different complexity, we show how these three currents are dynamically coupled, unravelling the large-scale connectivity. Further, we produce a conceptual theory how this current system follows from an idealized pattern of wind stress and buoyancy forcing.
Ocean Sci. Discuss., 12, 2231-2256, doi:10.5194/osd-12-2231-2015, 2015
Recent transient tracer distributions in the Fram Strait: estimation of anthropogenic carbon content and transport
Ocean Sci. Discuss., 12, 2189-2229, doi:10.5194/osd-12-2189-2015, 2015
The flow field of the upper hypoxic Eastern Tropical North Atlantic oxygen minimum zone
Summary: The subsurface circulation in the eastern tropical North Atlantic OMZ is derived from velocity-, float- and tracer data and data assimilation results and shows a cyclonic flow around the Guinea Dome reaching into the oxygen minimum zone. The stronger cyclonic flow around the Guinea Dome in 2009 seem to be connected to a strong Atlantic Meridional Mode (AMM) event. A continuous deoxygenation trend of the low oxygen layer was confirmed. Eddy influence is weak south of the Cape Verde Islands.
Ocean Sci. Discuss., 12, 2147-2187, doi:10.5194/osd-12-2147-2015, 2015
The near-inertial variability of meridional overturning circulation in the South China Sea as shown by an eddy-resolving ocean reanalysis
Summary: In this paper, we has used an 3-hourly eddy-resolving ocean reanalysis to depict the near-inertial (several days) variability. It is found that there is a significant near-inertial imprint in the SCSMOC. The imprint of near-inertial gravity waves (NIGWs) on the SCSMOC highlights the possible importance NIGWs in the horizontal and vertical redistribution of wind energy throughout the SCS. The breaking of these deep ocean NIGWs could be a candidate for the enhanced mixing in the SCS.
Ocean Sci. Discuss., 12, 2123-2146, doi:10.5194/osd-12-2123-2015, 2015
Wind forcing and fate of Sardinella aurita eggs and larvae in the Sicily Channel (Mediterranean Sea)
Ocean Sci. Discuss., 12, 2097-2121, doi:10.5194/osd-12-2097-2015, 2015
The role of vertical shear on the horizontal oceanic dispersion
Summary: The paper investigates the role of vertical shear on the horizontal oceans dispersion of tracer particles or concentrations fields. We compare in-situ measurements to GCM numerical data of the magnitude and the temporal correlation features of the vertical shear, and we discuss how an appropriate sub-grid scale parameterization can account for the observations. The analysis focuses on the mixed layer, and on the geographical region of the Mediterranean Sea.
Ocean Sci. Discuss., 12, 2073-2096, doi:10.5194/osd-12-2073-2015, 2015
Seasonal renewal time variability in the Curonian Lagoon caused by atmospheric and hydrographical forcing
Summary: The manuscript explores the importance of physical forcing on the exchange mechanisms and the renewal time in the Curonian Lagoon over ten years. The influence of ice cover on the exchange rates has been explored. Finally, the influence of water level fluctuations and river discharge has been studied. It has been found that ice cover is surprisingly not very important for changes in renewal time. The single most important factor is river discharge.
Ocean Sci. Discuss., 12, 2043-2072, doi:10.5194/osd-12-2043-2015, 2015
Simulation of the mantle and crustal helium isotope signature in the Mediterranean Sea using a high-resolution regional circulation model
Summary: Helium isotopes are a powerful tool in Earth sciences. We present the first simulation of the terrigenic helium isotope distribution in the whole Mediterranean Sea, using a high-resolution model (NEMO-MED12). In addition to providing constraints on helium isotope degassing fluxes in the Mediterranean, our simulations provide information on the ventilation of the deep Mediterranean waters which are useful for assessing NEMO-MED12 performance.
Ocean Sci. Discuss., 12, 2007-2041, doi:10.5194/osd-12-2007-2015, 2015
Self-Organizing Maps approaches to analyze extremes of multivariate wave climate
Summary: The analysis presented in the paper aim at extending the classification capabilities of Self-Organizing Maps within the context of ocean waves. Indeed, the intrinsic SOM difficulty in representing extremes of the wave climate is discussed and alternative strategies are proposed in order to represent the whole wave climate at a given location. Among them, a two-step SOM together with a double-side map provides the best results.
Ocean Sci. Discuss., 12, 1971-2006, doi:10.5194/osd-12-1971-2015, 2015
Technical Note: Could benzalkonium chloride be a suitable alternative to mercuric chloride for preservation of seawater samples?
Summary: We assess benzalkonium chloride (BAC) as alternative to mercuric chloride (HgCl2) for preservation of seawater samples. BAC concentrations of 50 mg dm–3 inhibited microbial activity for at least 3 days, possibly longer when chlorophyll a concentrations were low. With fewer risks to health and environment, and lower waste disposal costs, BAC could be a short-term alternative to HgCl2, but cannot replace it in the case of oxygen triple isotope analysis, which requires storage over weeks to months.
Ocean Sci. Discuss., 12, 1953-1969, doi:10.5194/osd-12-1953-2015, 2015
A combined quality-control methodology in Ebro Delta (NE Spain) high frequency radar system
Summary: In this paper, we provide a detailed description of an integrated approach to ensure the acquisition of high-quality surface current data, which remains as a priority for HF radar operators and the research community. This work should be of interest to readers in the areas of operational oceanography and also to a broad community of end-users since HF radar technology has many practical applications, encompassing both commercial and research uses.
Ocean Sci. Discuss., 12, 1913-1952, doi:10.5194/osd-12-1913-2015, 2015
A semi-analytical model for diffuse reflectance in marine and inland waters
Ocean Sci. Discuss., 12, 1893-1912, doi:10.5194/osd-12-1893-2015, 2015
Impact of variable sea-water conductivity on motional induction simulated with an OGCM
Ocean Sci. Discuss., 12, 1869-1891, doi:10.5194/osd-12-1869-2015, 2015
Design and validation of MEDRYS, a Mediterranean Sea reanalysis over 1992–2013
Summary: The paper describes MEDRYS, a MEDiterranean sea ReanalYsiS at high resolution for the period 1992-2013. The NEMOMED12 ocean model is forced at the surface by a new high resolution atmospheric forcing dataset (ALDERA). Altimeter data, satellite SST and temperature and salinity vertical profiles are jointly assimilated. The ability of the reanalysis to represent the sea surface high frequency variability, water mass characteristics, and transports through the Strait of Gibraltar is pointed out.
Ocean Sci. Discuss., 12, 1815-1867, doi:10.5194/osd-12-1815-2015, 2015
Spatial scales of temperature and salinity variability estimated from Argo observations
Ocean Sci. Discuss., 12, 1793-1814, doi:10.5194/osd-12-1793-2015, 2015
On the feasibility of the use of wind SAR to downscale waves on shallow water
Summary: High resolution wave hindcast has been performed for northern Adriatic Sea using a hybrid methodology, combining a regional wave hindcast data base, wind reanalysis, satellite SAR wind fields and data mining techniques. Comparison with in situ instrumental data indicate the good quality of the downscaled waves, moreover a good correlation was found on the downscaled waves forced with different wind fields. Results demonstrates how SAR wind fields can be successfully up-taken in wave downscaling.
Ocean Sci. Discuss., 12, 1567-1593, doi:10.5194/osd-12-1567-2015, 2015
Combining operational models and data into a dynamic vessel risk assessment tool for coastal regions
Summary: A combined methodology to estimate time and space variable shoreline risk levels from ships has been developed, integrating metocean forecasts and oil spill simulations with vessel tracking automatic identification systems (AIS) and coastal vulnerability indices. Results show the ability of the proposed methodology to estimate the risk properly sensitive to dynamic metocean conditions and oil transport behaviour, enhancing the maritime situational awareness and the decision support model.
Ocean Sci. Discuss., 12, 1327-1388, doi:10.5194/osd-12-1327-2015, 2015
Multi-objective entropy evolutionary algorithm for marine oil spill detection using cosmo-skymed satellite data
Summary: This study has demonstrated work to optimize the oil spill footprint detection in synthetic aperture radar (SAR) data. Therefore, Entropy-based Multi-objective Evolutionary Algorithm (E-MMGA) has implemented with COSMO-SkyMed data during the oil spill event along the coastal water of along Koh Samet island, Thailand. Besides, Pareto optimal solution is implemented with E-MMGA to minimize the difficulties of oil spill footprint boundary detection because of the existence of look-alike in SAR.
Ocean Sci. Discuss., 12, 1263-1289, doi:10.5194/osd-12-1263-2015, 2015
Carbon-based phytoplankton size classes retrieved via ocean color estimates of the particle size distribution
Summary: Recent advances in ocean color remote sensing have allowed the quantification of the particle size distribution (and thus volume) of suspended particles in surface waters, using their backscattering signature. Here we leverage these developments and use volume-to-carbon allometric relationships to quantify phytoplankton carbon globally using SeaWiFS ocean color data. Phytoplankton carbon concentrations are partitioned among three size classes - picoplankton, nanoplankton, microplankton.
Ocean Sci. Discuss., 12, 573-644, doi:10.5194/osd-12-573-2015, 2015