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14 pages, 9 figures, Nowadays Earth observation satellites provide information about many relevant variables of the ocean-climate system, such as temperature, moisture, aerosols, etc. However, to retrieve the velocity field, which is the most relevant dynamical variable, is still a technological challenge, specially in the case of oceans. New processing techniques, emerged from the theory of turbulent flows, have come to assist us in this task. In this paper, we show that multifractal techniques applied to new Sea Surface Temperature satellite products opens the way to build maps of ocean currents with unprecedented accuracy. With the application of singularity analysis, we show that global ocean circulation patterns can be retrieved in a daily basis. We compare these results with high-quality altimetry-derived geostrophic velocities, finding a quite good correspondence of the observed patterns both qualitatively and quantitatively; and this is done for the first time on a global basis, even for less active areas. The implications of this findings from the perspective both of theory and of operational applications are discussed, This is a contribution to the EU MERSEA project (AIP3-CT-2003-502885) and to the Spanish projects OCEANTECH (PIF 2006 project) and MIDAS-4 (ESP2005-06823-C05-1)

Special section Modeling Transport (Energy) Demand and Policies.-- 14 pages, 2 figures, 2 tables, 6 appendix, A global alternative mix to fossil fuels is proposed, based on proven renewable energy technologies that do not use scarce materials. The mix consists of a combination of onshore and offshore wind turbines, concentrating solar power stations, hydroelectricity and wave power devices attached to the offshore turbines. Solar photovoltaic power could contribute to the mix if its dependence on scarce materials is solved. The most adequate deployment areas for the power stations are studied, as well as the required space. Material requirements are studied for the generation, power transport and for some future transport systems. The order of magnitude of copper, aluminium, neodymium, lithium, nickel, zinc and platinum that may be required for the proposed solution is obtained and compared with available reserves. Overall, the proposed global alternative to fossil fuels seems technically feasible. However, lithium, nickel and platinum could become limiting materials for future vehicles fleet if no global recycling systems were implemented and rechargeable zinc-air batteries would not be developed; 60% of the current copper reserves would have to be employed in the implementation of the proposed solution. Altogether, they may become a long-term physical constraint, preventing the continuation of the usual exponential growth of energy consumption. © 2011 Elsevier Ltd

8 pages, 1 figure, 4 tables, Automated Taxon Identification (ATI) systems that use a database to identify species or anatomical structures of species from different taxonomical groups have recently been developed. However, few of these works have been applied to marine organisms. In this paper we develop an ATI system for identifying Actynopterigian species from their otolith contour; this is important information for the palaeontological, ictiological and ecological sciences, especially in food web studies. The AFORO website comprises the first web-based automated species identification system based exclusively on otolith shape outline. Species are identified iteratively based on a multiscale representation of the otolith contour. The ATI system is very easy to use as it only requires uploading a suitably oriented otolith image on a black background. Two tests were carried out with a database of 1480 images of left sacullar otoliths (sagittae) from 420 species. The first test analysed 50 different otoliths, 10 per species, from 5 different species. The second test identified 50 otoliths, each from a different species. The two tests obtained similar results (percentage of correct identifications): 72% of specimens were correctly identified at species level, and the percentage increased to 90% at genus level and reached 94% at family level. The best results are obtained for species which have an otolith contour with a very specific morphology, such as the mackerel Scomber colias, and the less efficient results for species with common shaped otoliths with unclear specific characteristics, such as the Mediterranean horse-mackerel Trachurus mediterraneus, or species with large morphological variability between individuals, such as Lophius budegassa or Synodus saurus, This work has been supported by the MICYT TIC2000-0376-p4-04, MEC PTR1995-0810-OP and MEC CGL2007-29846-E/BOS projects

Transport and mixing properties of surface currents can be detected from altimetric data by both Eulerian and Lagrangian diagnostics. In contrast with Eulerian diagnostics, Lagrangian tools like the local Lyapunov exponents have the advantage of exploiting both spatial and temporal variability of the velocity field and are in principle able to unveil subgrid filaments generated by chaotic stirring. However, one may wonder whether this theoretical advantage is of practical interest in real-data, mesoscale and sub-mesoscale analysis, because of the uncertainties and resolution of altimetric products, and the non-passive nature of biogeochemical tracers. Here we compare the ability of standard Eulerian diagnostics and the finite-size Lyapunov exponent in detecting instantaneous and climatological transport and mixing properties in the south-western Mediterranean. By comparing with sea-surface temperature patterns, we find that the two approaches provide similar results for slowly evolving eddies like the first Alboran gyre. However, the Lyapunov exponent is also able to predict the (sub-)mesoscale filamentary processes occurring along the Algerian current and above the Balearic Abyssal Plain. Such filaments are also observed, with some mismatch, in sea-surface temperature patterns. Climatologies of Lyapunov exponents do not show any compact relation with other Eulerian diagnostics, unveiling a different structure even at the basin scale. We conclude that filamentation dynamics can be detected by reprocessing available altimetric data with Lagrangian tools, giving insight into (sub-)mesoscale stirring processes relevant to tracer observations and complementing traditional Eulerian diagnostics. (C) 2008 Elsevier Ltd. All rights reserved.

A methodology for recovering salinity from expendable bathythermograph (XBT) data is presented. The procedure exploits climatological relationships between temperature, salinity and depth to build regional characteristic curves by fitting a polynomial function that minimises both the variance of residuals and unknowns. Hence, salinity is computed and recovered as a function of temperature and depth. Empirical formula are provided to recover the salinity field from temperature-depth measurements for the Cantabrian Sea and Galician Area. The method is validated and applied in the context of two marine rescue exercises carried out in the Bay of Biscay close to the north coast of Spain and in the Finisterre region, where a series of XBT and conductivity-temperature-depth (CTD) profiles were acquired during fast samplings. The results agree reasonably well with independent data in terms of the spatial structure, with the largest errors in the upper 100 m of the ocean and at intermediate levels. The first diagnoses of the surface geostrophic velocity fields obtained through the salinity reconstruction are coherent and may help in rescue and safety operations during marine emergencies. Hence, we recommend that a technical unit should consider this kind of expandable sampling strategy with both XBT and XCTD data during marine emergencies, since it provides useful and comprehensive information rapidly with minimal interference by means of formal operations on board search and rescue ships., Presentamos una metodología para el cálculo de la salinidad a partir de datos de XBT. El procedimiento hace uso de la relación climatológica S-T-d para construir curvas características de la región ajustando una función polinomial que minimiza tanto la varianza del residuo como de las incógnitas. De esta manera, la salinidad es calculada en función de la temperatura y la profundidad. Estas expresiones empíricas se han empleado para estimar el campo de salinidad a partir de medidas de temperatura y profundidad realizadas en el Mar Cantábrico y en el área de Galicia. El método se ha validado y aplicado en el contexto de dos ejercicios de salvamento marítimo, llevados a cabo en el Golfo de Vizcaya y en la región de Finisterre, donde se lanzaron XBT’s en muestreos rápidos y se obtuvieron perfiles de CTD. Los resultados muestran una coherencia razonable al compararlos con datos independientes en términos de la estructura espacial, con errores más importantes en los 100 m superiores de la columna de agua y en capas intermedias. Los primeros diagnósticos de la velocidad geostrófia en superficie son igualmente coherentes y pueden ser de gran ayuda en operaciones de salvamento y rescate durante emergencias en el mar. Por tanto, recomendamos a la Unidad Técnica que en situaciones de emergencia considere la posibilidad de realizar campañas con sondas desechables (XBT’s y XCTD’s), en tanto que este proceso es rápido, no interfiere con otras operaciones de salvamento y ofrece información de gran utilidad.

12 pages, 13 figures, 1 table, The surface salinity response to changes of various external forcings and model parameters is investigated in a regional 1/3° configuration of the NEMO-OPA model implemented over the eastern North-Atlantic subtropical Ocean. Fourteen realistic climatological simulations are run. By default, neither relaxation to climatological surface salinity nor temperature is included. Forcing fields and parameters expected to impact the surface salinity are modified. These include: the wind stress, the surface temperature, wind speed and relative humidity entering the bulk calculation for sensible and latent heat fluxes, the precipitation, the data specified at open boundaries, the lateral viscosity operator, the salt lateral diffusivity, the vertical mixing scheme, the on/off switch of the double diffusion parameterization, the river runoffs and the SSS/SST restoring terms. The SSS standard deviation over this ensemble of model simulations is of the order of 0.1 psu, which is also the order of the annual cycle of the surface salinity field in this area., In this experimental framework, the wind stress is found to have the largest impact on the model SSS, both in terms of mean field and annual variability. The sensitivity to the precipitation, atmospheric temperature, open boundary external data, and to the relaxation to climatological SSS and SST, is also significant. Of all the model parameterizations, the lateral salt diffusivity is the one associated to the strongest surface salinity model response. This work allows the identification of the main sources of error for model surface salinity. It paves the way for a more comprehensive investigation of SSS model error statistics, which is needed for future data assimilation experiments motivated by the close launch of the new SSS-observing SMOS and Aquarius satellite missions, This work was supported by the Spanish National Program on Space, under contracts ESP2004-00671 and ESP2005-06823-C05

2 pages, 2 figures.-- PAMM Special issue: "Sixth International Congress on Industrial Applied Mathematics (ICIAM07) and GAMM Annual Meeting, Zürich 2007", We summarize recent work on the location of Lagrangian structures in velocity fields obtained from realistic simulations and from satellite altimetry of the surface layers of the Mediterranean sea. Finite-size Lyapunov exponents are found to be useful quantities to characterize stretching and compressing structures, and their implications for mixing. Direct calculation of hyperbolic points and their stable and unstable manifolds identifies ocean structures, and allows the use of the tools of lobe dynamics to characterize fluid transport, Parts of this work have been supported by CSIC (grants PI-200650I224 and OCEANTECH), Royal Society-CSIC cooperation agreement (B2003GB03), MEC and FEDER (projects IMAGEN, CONOCE2 and FISICOS), ONR (Grant No. N00014-01-1-0769), and European Commission (projects MERSEA and 024717-DEMETRA)

17 pages, 7 figures, 2 tables, Because of the optimal features of wavelet processing, the use of wavelets for describing and analyzing signals in 2D turbulence has been generalized since a decade ago. In spite of the close analogy between 2D turbulence and geophysical fluid dynamics, few works have tried to generalize the rich framework of wavelet techniques to the study of experimental signals in oceanography. In this paper, the authors extend a prominent wavelet technique designed for the study of direct numerical simulations (DNSs) on 2D turbulence, the coherent vortex simulation, and analyze with it ocean velocity fields obtained from sea surface height maps derived from satellite altimetry. The authors demonstrate the pertinence of this technique to describe altimetry data, resulting in a description of oceanic flows with a reduced number of degrees of freedom. In particular, it is shown that the western Mediterranean circulation is well approximated by a field of extracted coherent vortices when an appropriate wavelet basis is employed as a filter; however, about one-third of the energy is lost in this description, evidencing important differences between results obtained on the frame of 2D turbulence and oceanic data, This is a contribution to the IMAGEN (Spanish R+D Plan: Grant REN2001-0802-C02-02) and MERSEA projects (Grant EU AIP3-CT- 2003-502885). A. Turiel is funded by a Ramón y Cajal fellowship from the Spanish Ministry of Education. The altimeter products were produced by Ssalto/Duacs and distributed by AVISO with support from CNES

10 pages, 4 figures We demonstrate the potential of monitoring coherent wave fronts on the tropical ocean surface using an advanced detection algorithm applied to visible sunglint-affected imagery from geostationary satellites. Data from MeteoSat are processed with the advanced analysis technique to reveal transient wave activity near and to the west of the Mascarene Ridge of the western Indian Ocean. The technique is based on a wavelet-based singularity analysis which enhances the subtle but highly coherent wave patterns in the meteorological satellite data. It is likely that the patterns represent internal ocean waves, a pathway to ocean mixing and climate. The prospect for using this detection algorithm in greatly expanded satellite global surveys of wave activity is outlined This is a contribution to the IMAGEN (Spanish R+D Plan: REN2001-0802-C02-02) and MERSEA projects (EU AIP3-CT-2003-502885). A. Turiel is funded by a Ramón y Cajal contract from the Spanish Ministry of Education. J. Isern-Fontanet is funded by a post-doctoral grant by the Spanish Ministry of Education. J. Young’s visit to ICM was provided by a sabbatical and Graduate School WARF funding from the University of Wisconsin-Madison. We thank EUMETSAT for leaving us their data

9 pages, 5 figures, A feature of marine plankton communities is the occurrence of rapid population explosions. When the blooming species are directly or indirectly noxious for humans, these proliferations are denoted as harmful algal blooms (HAB). The importance of biological interactions for the appearance of HABs, in particular when the proliferating microalgae produce toxins that affect other organisms in the food web, remains still poorly understood. Here we analyse the role of toxins produced by a microalgal species and affecting its predators, in determining the success of that species as a bloom former. A three-species predator–prey model is used to define a criterion that determines whether a toxic microalga will be able to initiate a bloom in competition against a non-toxic one with higher growth rate. Dominance of the toxic species depends on a critical parameter that defines the degree of feeding selectivity by grazers. The criterion is applied to a particular simplified model and to numerical simulations of a full marine ecosystem model. The results suggest that the release of toxic compounds affecting predators may be a plausible biological factor in allowing the development of HABs, We acknowledge the support from BIOHAB (Biological control of Harmful Algal Blooms in European coastal waters) project funded by the European Commission Program on Environment and Sustainable Development of Marine Ecosystems (ESD, FP-V, Key Action 3) under contract EVK3-CT-1999- 00015. We are grateful to two anonymous referees for very helpful criticism and constructive comments

6 pages, 3 figures., [EN] We present an automatic system for describing and identifying fish otolith shapes combining information technologies with modern advances in signal analysis. As a major novelty with respect to past studies the system includes wavelets (WT) and curvature space scale (CSS) analyses that have been shown to provide local morphologic information and characteristics (landmarks) of the sagitta otolith outline for non-specialists. By applying this electronic catalogue directly the system is very helpful for determining teleostean fish size, population and species. Both the electronic catalogue and the shape analysis are implemented through the AFORO database, which at present contains more than 1250 high resolution images of the left sagitta from 292 species and 94 families of teleostan fishes sampled mainly in Mediterranean and Antarctic waters, [ES] Se ha elaborado un sistema automático que describe e identifica las formas de otolitos de peces a partir de la combinación de tecnologías de la información y modernos avances en análisis de señal. Respecto a otros sistemas, éste presenta como principal novedad el uso de análisis de formas basados en la aplicación de wavelets (WT) y análisis de la curvatura a diferentes escalas (CSS). Estos análisis proporcionan información local de las características morfológicas del contorno externo del otolito de forma automática, facilitando la labor de identificación a no especialistas en morfología de otolitos. Una aplicación directa de este sistema facilitará la determinación del tamaño, la población y la especie en peces Teleósteos. Ambos, el sistema de análisis de formas y el catálogo de otolitos se implementan en la base de datos AFORO, que incluye actualmente, más de 1250 imágenes de alta resolución de otolitos pertenecientes a 292 especies y 94 familias de peces Teleósteos, procedentes básicamente del mar Mediterráneo y del océano Antártico, This work has been supported by the Spanish MICYT TIC2000-0376-p4-04 project