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Bahamon N.,CSIC - Center for Advanced Studies of Blanes | Aguzzi J.,CSIC - Institute of Marine Sciences | Bernardello R.,University of the Sciences in Philadelphia | Ahumada-Sempoal M.-A.,University of the Sea | And 5 more authors.
Sensors | Year: 2011

The new pelagic Operational Observatory of the Catalan Sea (OOCS) for the coordinated multisensor measurement of atmospheric and oceanographic conditions has been recently installed (2009) in the Catalan Sea (41°39'N, 2°54'E; Western Mediterranean) and continuously operated (with minor maintenance gaps) until today. This multiparametric platform is moored at 192 m depth, 9.3 km off Blanes harbour (Girona, Spain). It is composed of a buoy holding atmospheric sensors and a set of oceanographic sensors measuring the water conditions over the upper 100 m depth. The station is located close to the head of the Blanes submarine canyon where an important multispecies pelagic and demersal fishery gives the station ecological and economic relevance. The OOCS provides important records on atmospheric and oceanographic conditions, the latter through the measurement of hydrological and biogeochemical parameters, at depths with a time resolution never attained before for this area of the Mediterranean. Twenty four moored sensors and probes operating in a coordinated fashion provide important data on Essential Ocean Variables (EOVs; UNESCO) such as temperature, salinity, pressure, dissolved oxygen, chlorophyll fluorescence, and turbidity. In comparison with other pelagic observatories presently operating in other world areas, OOCS also measures photosynthetic available radiation (PAR) from above the sea surface and at different depths in the upper 50 m. Data are recorded each 30 min and transmitted in real-time to a ground station via GPRS. This time series is published and automatically updated at the frequency of data collection on the official OOCS website (http://www.ceab.csic.es/~oceans). Under development are embedded automated routines for the in situ data treatment and assimilation into numerical models, in order to provide a reliable local marine processing forecast. In this work, our goal is to detail the OOCS multisensor architecture in relation to the coordinated capability for the remote, continuous and prolonged monitoring of atmospheric and oceanographic conditions, including data communication and storage. Accordingly, time series of measurements for a number of biological parameters will be presented for the summer months of 2011. Marine hindcast outputs from the numerical models implemented for simulating the conditions over the study area are shown. The strong changes of atmospheric conditions recorded in the last years over the area have altered the marine conditions of living organisms, but the dimension of the impact remains unclear. The OOCS multisensor coordinated monitoring has been specifically designed to address this issue, thus contributing to better understand the present environmental fluctuations and to provide a sound basis for a more accurate marine forecast system. © 2011 by the authors; licensee MDPI, Basel, Switzerland. Source


Ahumada-Sempoal M.-A.,University of the Sea | Flexas M.M.,Jet Propulsion Laboratory | Bernardello R.,UK National Oceanography Center | Bahamon N.,CSIC - Center for Advanced Studies of Blanes | And 2 more authors.
Continental Shelf Research | Year: 2015

A climatological simulation performed with a fine-resolution (~1.2. km) 3D circulation model nested in one-way to a coarse-resolution (~4. km) 3D regional model is used to examine the cross-shelf break water exchange in the Blanes submarine canyon (~41°00'-41°46'N; ~02°24'-03°24'E). A Lagrangian particle-tracking model coupled to the fine-resolution 3D circulation model is used to investigate the role of the incident regional flow (i.e. the Northern Current, NC) and its seasonal variability on the dispersion and residence time of passive particles inside Blanes Canyon. The NC flows southwestward, along the slope, with the coastline to the right. Water is advected offshore/onshore at the upstream/downstream canyon walls, with a net water transport toward the slope (i.e. offshore). The amount of water moved across the shelf break of the upstream wall is approximately three times larger than the amount moved across the shelf break of the downstream wall. This preferential zone for cross-shelf break water exchange is explained by the asymmetric geometry of the canyon and the orientation of the incident current with respect to the canyon bathymetry. Passive particles released upstream Blanes Canyon between the mid-shelf and the upper-slope drift within the NC and accumulate over the shelf edge of the canyon. About half of the particles released at depths above the shelf break move towards shallower areas inside the canyon. In contrast, about two-thirds of particles released below the shelf break move to deeper areas. Particle dispersion is higher under weakly (e.g. winter) than strongly (e.g. summer) stratified conditions. The residence time of passive particles inside the canyon (~4-6 days) is double than the residence time downstream of the canyon, indicating that the canyon acts as an efficient retention zone for passive particles. © 2015 Elsevier Ltd. Source


Ahumada-Sempoal M.-A.,University of the Sea | Flexas M.M.,CSIC - Mediterranean Institute for Advanced Studies | Flexas M.M.,Jet Propulsion Laboratory | Bernardello R.,University of Pennsylvania | And 2 more authors.
Progress in Oceanography | Year: 2013

A high-resolution (~1.2. km) 3D numerical model was used to analyze the interaction of the Northern Current (a right-bounded flow) with the Blanes submarine canyon (BC, NW Mediterranean). Although it refers to a climatological simulation the model properly suites our purpose since it simulates the Northern Current (NC) mesoscale variability, as well as its seasonal variability. Model results were validated with satellite sea surface temperature and current-meter data. The simulated NC tends to be faster and deeper in winter, and slower and shallower in summer. According to our results, NC meanders and eddies are recurrent in the BC area and produce highly fluctuating three-dimensional circulation patterns within the canyon. We found that NC meanders and anticyclonic eddies propagating along the current pathway tend to be deep and, consequently, their effects extend down to the deeper part of the BC. We also found that the meandering of the NC plays a key role in enhancing vertical motions inside the BC. Upwelling and downwelling events occurring on timescales of 4-20. days are associated with NC meanders crests and troughs passing over the BC. Net upwelling/downwelling events are accordingly influenced by the NC seasonality. They are more predominant in winter, while damped in summer. Our results show the importance of NC meanders in creating local net upwelling/downwelling and strengthen the evidence that continuous right-bounded (downwelling favorable) flows can also produce net upwelling inside submarine canyons. © 2013 Elsevier Ltd. Source


Cardoso-Mohedano J.G.,National Autonomous University of Mexico | Bernardello R.,UK National Oceanography Center | Sanchez-Cabeza J.A.,National Autonomous University of Mexico | Molino-Minero-Re E.,National Autonomous University of Mexico | And 2 more authors.
Estuarine, Coastal and Shelf Science | Year: 2015

Coastal lagoons provide important ecosystem services worldwide but are subject to high and multiple environmental stresses. Little information exists on the inner creeks of low-flow coastal lagoons, where the low-exchange rates may exacerbate anthropogenic impacts. In this work, we used a model with high spatio-temporal resolution to describe the hydrodynamics and to estimate the accumulation of conservative contaminants in the upper estuary of the Urias sub-tropical coastal lagoon, in northwestern Mexico. The lagoon shows a weak anti-estuarine behavior and its hydrodynamics is governed by astronomical tides and topography. The mean steady-state water age in the three lagoon areas was ~15, ~30 and ~70 days in the Harbor, Intermediate and Upper Areas, respectively. Thus, the Upper Area, which shelters a mangrove forest, is the most vulnerable to pollution due to the high potential for accumulation. As a best case scenario, the simulation of the release of conservative substances in the Upper area indicated that, 50 days after the release started, conservative pollutants mostly remained in the Upper Area and were not significantly exported to the open ocean. This methodology can be used to model the impact of conservative substances in coastal lagoons worldwide, and can be complementary and useful for the optimization of long-term coastal zone management activities. © 2015 Elsevier Ltd. Source


Bernardello R.,CSIC - Center for Advanced Studies of Blanes | Bernardello R.,University of Pennsylvania | Cardoso J.G.,CSIC - Center for Advanced Studies of Blanes | Cardoso J.G.,Grupo Mexico | And 5 more authors.
Biogeosciences | Year: 2012

Mid-latitude spring blooms of phytoplankton show considerable year-to-year variability in timing, spatial extent and intensity. It is still unclear to what degree the bloom variability is connected to the magnitude of the vertical flux of organic matter. A coupled three-dimensional hydrodynamic-biogeochemical model is used to relate interannual variability in phytoplankton spring-bloom dynamics to variability in the vertical export of organic matter in the NW Mediterranean Sea. Simulation results from 2001 to 2010, validated against remote-sensing chlorophyll, show marked interannual variability in both timing and shape of the bloom. Model results show a tendency for the bloom to start later after cold and windy winters. However, the onset of the bloom occurs often when the mixed layer is still several hundred metres deep while the heat flux is already approaching zero and turbulent mixing is low. Frequency and intensity of wind episodes control both the timing and development of the bloom and the consequent export flux of organic matter. The wintertime flux is greater than zero and shows relatively low interannual variability. The magnitude of the interannual variability is mainly determined in March when the frequency of windy days positively correlates with the export flux. Frequent wind-driven mixing episodes act to increase the export flux and, at the same time, to interrupt the bloom. Perhaps counterintuitively, our analysis shows that years with discontinuous, low-chlorophyll blooms are likely to have higher export flux than years with intense uninterrupted blooms. The NW Mediterranean shows strong analogy with the North Atlantic section within the same latitude range. Hence, our results may also be applicable to this quantitatively more important area of the world ocean. © 2012 Author(s). Source

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