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
Monitoring Atlantic overturning circulation variability with GRACE-type ocean bottom pressure observations – a sensitivity study
Summary: The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism for large-scale northward heat transport and plays an important role for global climate. Previously, AMOC changes have been inferred from in-situ ocean bottom pressure (OBP) observations at single latitudes. We extent the analysis to space-based observations (and the whole North Atlantic) and show on data from an ocean model that AMOC anomalies can be inferred from OBP at a resolution resembling the GRACE gravity mission.
Ocean Sci. Discuss., 12, 1765-1791, doi:10.5194/osd-12-1765-2015, 2015
Turbulence observations in the Gulf of Trieste under moderate wind forcing and different water column stratification
Summary: Between January 30th and February 4th we collected the first turbulence observations in the Gulf of Trieste under different wind forcing and water column structure. The vertical profiles of the turbulence kinetic energy dissipation rates showed that the presence near the sea floor of different water masses, inflowing from the open sea, can prevent the complete mixing of the water column. This dumping effect is enhanced when these masses present higher suspended sediment concentrations.
Ocean Sci. Discuss., 12, 1729-1764, doi:10.5194/osd-12-1729-2015, 2015
Technical Note: Medium-term morphodynamics in an unprotected sandy beach of the Adriatic Sea
Summary: The characterization of bar geometry and dynamics in an unprotected sandy beach of the Middle Adriatic is here presented. Coupling of climate and bathymetric surveys suggests that time periods dominated by waves coming from NNE, i.e. almost perpendicular to the coast, promote seaward migration, partial destruction and smoothing of the submerged bars. Conversely, periods dominated by waves from ESE, i.e. angled w.r.t. shoreline, induce shoreward migration, regeneration and steepening of the bars.
Ocean Sci. Discuss., 12, 1711-1728, doi:10.5194/osd-12-1711-2015, 2015
Responses of atmospheric circulation to sea surface temperature anomalies in the South China Sea
Summary: The SST anomalies in the SCS and their influences on global atmospheric circulation were studied. The results of the simple atmospheric model suggested that the SCS SST anomalies can induce several barotropic wave trains from the SCS to other regions. The baroclinic stream function anomalies from the simple model showed an anticyclonic vortex pair and a cyclonic vortex pair.
Ocean Sci. Discuss., 12, 1693-1710, doi:10.5194/osd-12-1693-2015, 2015
High resolution satellite turbidity and sea surface temperature observations of river plume interactions during a significant flood event
Ocean Sci. Discuss., 12, 1669-1692, doi:10.5194/osd-12-1669-2015, 2015
Investigation of model capability in capturing vertical hydrodynamic coastal processes: a case study in the North Adriatic Sea
Summary: First modeling work comparing SHYFEM and MITgcm performance in the North Adriatic Sea; the treatment of heat/mass fluxes at the surface affects the models skill to reproduce coastal processes; high resolution is needed close to the coast, while lower resolution in the offshore is adequate to capture the dense water event; correct river discharges and temperature are vital for the reproduction of estuarine dynamics; nonhydrostatic processes do not influence the dense water formation.
Ocean Sci. Discuss., 12, 1625-1668, doi:10.5194/osd-12-1625-2015, 2015
The Civitavecchia Coastal Environment Monitoring System (C-CEMS): a new tool to analyse the conflicts between coastal pressures and sensitivity areas
Summary: The Civitavecchia Coastal Environment Monitoring System (C-CEMS) has been developed by the Laboratory of Experimental Oceanology and Marine Ecology in order to analyse the conflicts between human pressures and ecosystem conservation. As examples the analysis of faecal bacteria dispersion for bathing water quality assessment and the evaluation of the effects of the dredged activities on Posidonia meadows are reported. Finally C-CEMS can be considered a new useful tool for coastal zone management.
Ocean Sci. Discuss., 12, 1595-1623, doi:10.5194/osd-12-1595-2015, 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
Bio-optical characterization and light availability parametrization in two glacial melt water influenced estuary systems (West-Greenland)
Summary: In 2012 measurements were conducted in two adjacent estuary systems on Greenland’s west coast which are strongly influenced by glacial melt water. Results described in this study show the relevance of inorganic SPM and Chl a alike, while colored dissolved organic matter is less prominent. Light availability was recorded throughout the cruise and an effective two component (Chl a and inorganic SPM) model for PAR is developed to fill observational gaps from insufficient light conditions.
Ocean Sci. Discuss., 12, 1537-1566, doi:10.5194/osd-12-1537-2015, 2015
Accuracy of the mean sea level continuous record with future altimetric missions: Jason-3 vs. Sentinel-3a
Summary: The reference Mean Sea Level record, essential for the understanding of climate evolution, is derived from the altimetric measurements of the TOPEX/Poseidon mission, followed by Jason-1 and later Jason-2 on the same orbit. Soon, Jason-3 will be launched on the same historical orbit, followed by Sentinel-3a on a new one. This paper shows linking missions with the same orbit allows to meet climate users requirements regarding the MSL trend while using Sentinel-3a would increase the uncertainty.
Ocean Sci. Discuss., 12, 1511-1536, doi:10.5194/osd-12-1511-2015, 2015
Biased thermohaline exchanges with the arctic across the Iceland-Faroe Ridge in ocean climate models
Ocean Sci. Discuss., 12, 1471-1510, doi:10.5194/osd-12-1471-2015, 2015
Mapping turbulent diffusivity associated with oceanic internal lee waves offshore Costa Rica
Summary: Lee waves play a significant role in ocean mixing, but are difficult to study with traditional casts, moorings, and tows due to their stationary nature and limited spatial extent. We develop a new method to estimate turbulent diffusivity from seismic data and find elevated levels of turbulence associated with lee waves in the midwater and around the seafloor that are 5 times greater than surrounding waters and 50 times greater than open ocean diffusivities.
Ocean Sci. Discuss., 12, 1433-1469, doi:10.5194/osd-12-1433-2015, 2015
Modeling ocean response to an extreme Bora event in Northern Adriatic using one-way and two-way atmosphere-ocean coupling
Summary: We compare the Northern Adriatic response to an extreme Bora event, as simulated by one-way and two-way atmosphere-ocean coupling. We show that two-way coupling yields significantly better estimates of heat fluxes, most notably sensible heat flux, across the air-sea interface. When compared to CTD observations in the Gulf of Trieste, two-way coupled system consequently leads to a better representation of ocean salinity, temperature, density, and even baroclinic circulation througout the event.
Ocean Sci. Discuss., 12, 1389-1431, doi:10.5194/osd-12-1389-2015, 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
Influence of natural surfactants on short wind waves in the coastal Peruvian waters
Ocean Sci. Discuss., 12, 1291-1325, doi:10.5194/osd-12-1291-2015, 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
Factors favouring large organic production in the northern Adriatic: towards the northern Adriatic empirical ecological model
Summary: Seasonal and interannual production changes in the northern Adriatic (NA) reflect on the total Adriatic bioproduction of certain species (i.e., anchovy). Long-term (1990-2004) phyto-abundance and geostrophic currents analysis relieves basic mechanism of NA biomass production changes. The results present a first step in building an empirical ecological model of the region, aiming to predict the amount of organic production in NA, which is to be used in the environmental management of the region.
Ocean Sci. Discuss., 12, 1219-1262, doi:10.5194/osd-12-1219-2015, 2015
Ocean modelling for aquaculture and fisheries in Irish waters
Ocean Sci. Discuss., 12, 1187-1217, doi:10.5194/osd-12-1187-2015, 2015
An improved method for the determination of dissolved nitric oxide (NO) in seawater samples
Ocean Sci. Discuss., 12, 959-981, doi:10.5194/osd-12-959-2015, 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