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Sea surface currents probably are the most relevant essential ocean variable affecting diverse societal challenges concerning the marine environmental (as, for example, safe and efficient navigation, marine pollution and ecological connectivity). This work introduces a climatological Atlas (monthly resolution) of currents in the Mediterranean and Canary–Iberian–Biscay basins, based on today's state of the art reanalyses of the ocean circulation. The focus is on surface and subsurface reanalyses (here understood as z∼0.5 and z∼15 m, respectively) provided by the Copernicus Marine Environment Monitoring Service (CMEMS). The climatological values are computed from the median of the empirical probability density functions and the Atlas also includes the variance matrix and a bimodality index to have quantitative information on their variability. For both domains, the subsurface climatological fields are reasonably consistent with circulation schemes proposed in the previous literature but clearly improving the time and space resolution of the emerging patterns. For the Canary–Iberian–Biscay domain, the monthly climatological surface currents capture accurately the characteristic seasonal signal and its transition between a favourable and non-favourable upwelling regime. In the Mediterranean basin, differences between the near-surface and the 15 m velocity fields suggest a non-negligible role of winds over the variability of the uppermost ocean layer, specially in the Eastern Mediterranean basin. This is, up to our knowledge, the first time that such near-surface climatological patterns are computed. It has been found that, in general, the resulting patterns agree with surface drifter trajectories. In several regions, interannual variability foster bimodal and multimodal probability distributions. The Atlas has been conceived with the purpose of providing a first quantitative assessment on the surface circulation, thus being a complementary tool of real-time ocean foreca

[EN] In this "In Depth" we talk with Jordi Isern about the tools, services and resources that ICATMAR makes available to the maritime community, [ES] En este “A Fondo” hablamos con Jordi Isern de las herramientas, servicios y recursos que el ICATMAR pone a disposición de la comunidad marítima, [CAT] En aquest l’”A Fons” parlem amb Jordi Isern de les eines, serveis i recursos que l’ICATMAR posa a disposició de la comunitat marítima

This study assesses the capability of Surface Quasi-Geostrophy (SQG) to reconstruct the three-dimensional (3D) dynamics in four critical areas of the Arctic Ocean: the Nordic, Barents, East Siberian, and Beaufort Seas. We first reconstruct the upper ocean dynamics from TOPAZ4 reanalysis of sea surface height (SSH), surface buoyancy (SSB), and surface velocities (SSV) and validate the results with the geostrophic and total TOPAZ4 velocities. The reconstruction of upper ocean dynamics using SSH fields is in high agreement with the geostrophic velocities, with correlation coefficients greater than 0.8 for the upper 400 m. SSH reconstructions outperform surface buoyancy reconstructions, even in places near freshwater inputs from river discharges, melting sea ice, and glaciers. Surface buoyancy fails due to the uncorrelation of SSB and subsurface potential vorticity (PV). Reconstruction from surface currents correlates to the total TOPAZ4 velocities with correlation coefficients greater than 0.6 up to 200 m. In the second part, we apply the SQG approach validated with the reanalysis outputs to satellite-derived sea level anomalies and validate the results against in-situ measurements. Due to lower water column stratification, the SQG approach’s performance is better in fall and winter than in spring and summer. Our results demonstrate that using surface information from SSH or surface velocities, combined with information on the stratification of the water column, it is possible to effectively reconstruct the upper ocean dynamics in the Arctic and Subarctic Seas up to 400 m. Future remote sensing missions in the Arctic Ocean, such as SWOT, Seastar, WaCM, CIMR, and CRISTAL, will produce enhanced SSH and surface velocity observations, allowing SQG schemes to characterize upper ocean 3D mesoscale dynamics up to 400 m with higher resolutions and lower uncertainties.

This study assesses the capability of Surface Quasi-Geostrophy (SQG) to reconstruct the three-dimensional (3D) dynamics in four critical areas of the Arctic Ocean: the Nordic, Barents, East Siberian, and Beaufort Seas. We first reconstruct the upper ocean dynamics from TOPAZ4 reanalysis of sea surface height (SSH), surface buoyancy (SSB), and surface velocities (SSV) and validate the results with the geostrophic and total TOPAZ4 velocities. The reconstruction of upper ocean dynamics using SSH fields is in high agreement with the geostrophic velocities, with correlation coefficients greater than 0.8 for the upper 400 m. SSH reconstructions outperform surface buoyancy reconstructions, even in places near freshwater inputs from river discharges, melting sea ice, and glaciers. Surface buoyancy fails due to the uncorrelation of SSB and subsurface potential vorticity (PV). Reconstruction from surface currents correlates to the total TOPAZ4 velocities with correlation coefficients greater than 0.6 up to 200 m. In the second part, we apply the SQG approach validated with the reanalysis outputs to satellite-derived sea level anomalies and validate the results against in-situ measurements. Due to lower water column stratification, the SQG approach’s performance is better in fall and winter than in spring and summer. Our results demonstrate that using surface information from SSH or surface velocities, combined with information on the stratification of the water column, it is possible to effectively reconstruct the upper ocean dynamics in the Arctic and Subarctic Seas up to 400 m. Future remote sensing missions in the Arctic Ocean, such as SWOT, Seastar, WaCM, CIMR, and CRISTAL, will produce enhanced SSH and surface velocity observations, allowing SQG schemes to characterize upper ocean 3D mesoscale dynamics up to 400 m with higher resolutions and lower uncertainties.

This study assesses the capability of Surface Quasi-Geostrophy (SQG) to reconstruct the three- dimensional (3D) dynamics in four critical areas of the Arctic Ocean: the Nordic, Barents, East Siberian, and Beaufort Seas. We first reconstruct the upper ocean dynamics from TOPAZ4 re- analysis of sea surface height (SSH), surface buoyancy (SSB), and surface velocities (SSV) and validate the results with the geostrophic and total TOPAZ4 velocities. The reconstruction of upper ocean dynamics using SSH fields is in high agreement with the geostrophic velocities, with correlation coefficients greater than 0.8 for the upper 400 m. SSH reconstructions outperform surface buoyancy reconstructions, even in places near freshwater inputs from river discharges, melting sea ice, and glaciers. Surface buoyancy fails due to the uncorrelation of SSB and subsurface potential vorticity (PV). Reconstruction from surface currents correlates to the total TOPAZ4 velocities with correlation coefficients greater than 0.6 up to 200 meters. Due to a lower stratification of the water column, the performance of the SQG approach is better in fall and winter than in the spring and summer. In the second part, we apply the SQG approach validated withthe reanalysis outputs to satellite-derived upper ocean currents and validate the results against in-situ measurements. Our results demonstrate that using surface information from SSH or surface velocities, combined with information on the stratification of the water column, it is possible to effectively reconstruct upper ocean dynamics in the Arctic and Subarctic Seas up to 400 meters. Future remote sensing missions in the Arctic Ocean, such as SWOT, Seastar, WaCM, CIMR, and CRISTAL, will produce enhanced SSH and surface velocities observations, allowing SQG schemes to characterize upper ocean 3D mesoscale dynamics up to 400 meters with higher resolution and lower uncertainties

In addition to their ecological and environmental value, coastal areas are of major economic and social importance. Thus, they are among the most impacted marine environments by anthropogenic pressures, such as high population density and intensive human activity, that produce an excess of nutrients delivered to coastal waters. Consequently, phytoplanktonic growth is enhanced, increasing chlorophyll-a concentration (Chl-a) and initiating the eutrophication process, that reduces water quality. In the Mediterranean Sea, its low tidal range (20-40 cm) makes difficult for continental inflows to dilute, which helps to maintain the eutrophication as a threat for coastal waters. European policies, such as the Marine Strategy Framework Directive (MSFD; 2000/60/EC) and the Water Framework Directive (WFD; 2000/60/EC), aim to restore and protect coastal waters. [...]

[EN] This will be done through the new operational oceanography service of ICATMAR, a cooperative body between ICM-CSIC and the Generalitat de Catalunya that aims to provide scientific advice on maritime issues, promote cooperation and boost marine research, [ES] Se realizará a través del nuevo servicio de oceanografía operacional del ICATMAR, un órgano de cooperación entre el ICM-CSIC y la Generalitat de Catalunya que tiene como objetivo asesorar científicamente en temas marítimos, promover la cooperación e impulsar la investigación marina, [CAT] Es farà a través del nou servei d’oceanografia operacional de l’ICATMAR, un òrgan de cooperació entre l’ICM-CSIC i la Generalitat de Catalunya que té com a objectiu assessorar científicament en temes marítims, promoure la cooperació i impulsar la recerca marina

We will delve into the intersection of technology and sustainability for coastal cities. How can the digital ocean, ocean data and the Internet of Things help coastal cities address sustainability? What is the role of AI in advancing smart, sustainable coastal cities and their Blue Economy? How can ocean data and monitoring improve marine spatial planning around coastal cities?

Satellite infrared radiometers have provided high resolution (~1 km) measurements of the ocean surface during the last forty years. The existence of such a time series enables us to investigate different dynamical regimes of the upper ocean and monitor potential changes related to global warming. The main problem, however, is to extract the dynamical characteristics of the upper ocean. This is motivated by two types of difficulties: data related limitations (cloud coverage, noise level, failure of cloud mask algorithms, etc.) and the availability of tools to extract information (statistical tools, dynamical frameworks, etc.) In this session, we proposed to review some of these tools based on the multifractal theory of turbulence and other approaches, and to discuss how they are impacted by data limitations

A keynote lecture was given by one of the GHRSST meeting hosts, Jordi Isern-Fontanet (CSIC-ICM) on the role of thermal fronts and how to characterise high resolution SST. While using spectral slopes is a common tool for assessing the effective spatial resolution of SST products, which typically exhibit a drop in power following a k-2 slope, there are limitations. A common approach in turbulence-related studies is to use structure functions which also exhibit power laws, with e.g. the 2nd order structure function being the spectral slope. A characteristic of turbulent flows is the anomalous scaling, i.e. the departure from a straight line, consistent for various order functions (2nd, 4th, 6th, 8th). Thus, singularity exponents are proposed as a proxy measure for front intensity. The spatial distribution of fronts characterises the scaling of the structure functions. Anomalous scaling is proportional to the intensity of the strongest front; this is robust result that can be theoretically predicted and it implies that if front intensity changes with season, anomalous scaling will also change, thus SST products need to be coherent with this feature. In summary, ocean fronts determine the scaling properties of structure functions, with most intense fronts controlling the anomalous scaling of structure functions. This has a direct practical use in the validation of SST products

Sea Surface Temperature (SST) plays an important role in the production of satellite based Sea Surface Salinity (SSS) observations. On the one hand, it is used as an auxiliary parameter for SSS retrieval from brightness temperature to produce L2 and L3 datasets. On the other hand, it is used as a template to increase spatial resolution using multifractal fusion techniques (L4 product). Traditionally, Soil Moisture and Ocean Salinity (SMOS) SSS datasets produced at the Barcelona Expert Center were based on OSTIA SST product. In this work, we revisit this election and assess different sources of satellite-derived SST products. The assessment will consist of: - comparison with in-situ data (ARGO floats); - performing a correlated triple collocation analysis [González- Gambau et al., 2020] between the different products to decide which one presents the lower uncertainty; - spectral and singularity analysis to assess the spatial resolution of each SST product [Hoareau et al. 2018].

In addition to their ecological and environmental value, coastal areas are of major economic and social importance. As a result, they are one of the marine environments most impacted by anthropogenic pressures, such as high population density and intensive human activity. Anthropogenic pressures produce an excess of nutrients which are delivered to coastal waters, triggering phytoplanktonic growth and eutrophication, reducing the water quality. Several policies have been enacted in Europe with the aim of restoring and protecting waters, such as the Water Framework Directive (WFD; 2000/60/EC) and the Marine Strategy Framework Directive (MSFD; 2000/60/EC). Traditionally, water quality assessments were based on in situ chlorophyll-a (Chl-a) concentration data. The ocean colour satellites (such as Sentinel-3) produced water quality maps with higher spatial and temporal resolution (300 m) than those derived from in situ data. As a result, they allowed to improve the required assessments of the above Directives. However, this information is only suitable for open waters and not for coastal ones, which require even higher spatial resolution due to their greater variability. Nowadays, the new generation of satellites, such as Sentinel-2 from the Copernicus Programme and its MSI sensor, produce ocean colour maps with very high spatial resolution (10-60 m), allowing for accurate assessment of water quality of coastal waters (Caballero, 2020; Poddar, 2019). This is especially true in the Mediterranean Sea, where the low tidal range (20-40 cm) makes difficult to dilute continental inflows. As a result, eutrophication is one of the greatest threats to Mediterranean coastal waters. The goal of the MARS project is to create Chl-a concentration maps for coastal waters, particularly the Mediterranean Sea, using satellite data. To achieve this goal, the Catalan coast was chosen as a case study for two reasons: i) this coast is representative of the NW Mediterranean and ii) the Nation

The contribution of ocean fronts to the properties and temporal evolution of Sea Surface Temperature (SST) structure functions have been investigated using a numerical model of the California Current system. First, the intensity of fronts have been quantified by using singularity exponents. Then, leaning on the multifractal theory of turbulence, we show that the departure of the scaling of the structure functions from a straight line, known as anomalous scaling, depends on the intensity of the strongest fronts. These fronts, at their turn, are closely related to the seasonal change of intensity of the coastal upwelling characteristics of this area. Our study points to the need to correctly reproduce the intensity of the strongest fronts and, consequently, properly model processes such as coastal upwelling in order to reproduce SST statistics in ocean models

Satellite altimeters provide quasi-global measurements of sea surface height, and from those the vertically integrated geostrophic velocity can be directly estimated, but not its vertical structure. This study discusses whether the mesoscale (30–400 km) dynamics of three regions in the South Atlantic can be described by the surface quasi-geostrophic (SQG) theory, both at the surface and in depth, using outputs from an ocean general circulation model. At these scales, the model surface eddy kinetic energy (EKE) spectra show slopes close to k−5/3 (k−3) in winter (summer), characterizing the SQG and quasi-geostrophic (QG) turbulence regimes. We use surface density and temperature to (a) reconstruct the stream function under the SQG theory, (b) assess its capability of reproducing mesoscale motions, and (c) identify the main parameters that improve such reconstruction. For mixed layers shallower than 100 m, the changes in the mixed-layer depth contributes nine times more to the surface SQG reconstruction than the EKE, indicating the strong connection between the quality of the reconstruction and the seasonality of the mixed layer. To further explore the reconstruction vertical extension, we add the barotropic and first baroclinic QG modes to the surface solution. The SQG solutions reproduce the model density and geostrophic velocities in winter, whereas in summer, the interior QG modes prevail. Together, these solutions can improve surface correlations (>0.98) and can depict spatial patterns of mesoscale structures in both the horizontal and vertical domains. Improved spatial resolution from upcoming altimeter missions poses a motivating scenario to extend our findings into future observational studies

[EN] Data acquisition, analysis and interpretation are essential tasks for science, business and administration, and research in this field has led to major developments. At the Institut de Ciències del Mar (ICM), researchers have progressed from recording data on paper to storing them on electronic devices or in the “cloud”. However, the organization, management and transfer of the data obtained –mostly thanks to public funding– still has many shortcomings. Several initiatives at the ICM are working to overcome these difficulties and organize the scientific data according to the FAIR principles that are applied internationally. […], [ES] La adquisición de datos, análisis y posterior interpretación es una tarea esencial para la ciencia, que requiere almacenar, organizar, acceder y transferir estos datos. Esta necesidad afecta también a otros sectores de la sociedad, como empresas o entidades de gobierno que utilizan los datos como una herramienta clave en la toma de decisiones. Esto ha hecho que la investigación en este campo haya sido muy activa y el almacenamiento y gestión de datos haya sufrido una evolución muy importante. En el Institut de Ciències del Mar (ICM) se ha vivido de cerca este cambio, pasando de tener los datos en papel a tenerlos en dispositivos electrónicos o en la “Nube”. Sin embargo, la organización, gestión y transferencia de los datos sigue teniendo muchas carencias. Diferentes iniciativas en el ICM están trabajando para superar las dificultades existentes y organizar la información científica obtenida a lo largo de tantos años, con la financiación de entes públicos fundamentalmente, en bases de datos siguiendo los principios FAIR (findability, accessibility, interoperability, reusability) de aplicación internacional en los datos científicos. […], [CAT] L’adquisició de dades, anàlisi i posterior interpretació és una tasca essencial per a la ciència, que requereix emmagatzemar, organitzar, accedir i transferir aquestes dades. Aquesta necessitat afecta també altres sectors de la societat, com empreses o entitats de govern que utilitzen les dades com una eina clau en la presa de decisions. Això ha fet que la recerca en aquest camp hagi estat molt activa i l’emmagatzematge i gestió de dades hagi sofert una evolució molt important. A l’Institut de Ciències del Mar (ICM) s’ha viscut de prop aquest canvi, passant de tenir les dades en paper a tenir-les en dispositius electrònics o al “Núvol”. Tot i així, l’organització, gestió i transferència de les dades segueix tenint moltes mancances. Diferents iniciatives a l’ICM estan treballant per a superar les dificultats existents i organitzar la informació científica obtinguda al llarg de tants anys, amb el finançament d’ens públics fonamentalment, en bases de dades seguint els principis FAIR (findability, accessibility, interoperability, reusability) d’aplicació internacional a les dades científiques. [...]

[EN] Those of us who are lucky enough to live by the sea have incorporated it into in our daily lives. We enjoy the blue horizon and its offer of a place for meeting and leisure. Contact with the sea through physical access arouses our curiosity. It drives us to learn about it and therefore to desire to maintain a sustainable relationship with it. “An accessible ocean”, one of the seven objectives of the UN Decade of Ocean Science for Sustainable Development, is therefore of paramount importance for our development and the future of our existence. […], [ES] Todos aquellos que tenemos la suerte de vivir cerca del mar hemos incorporado, sin darnos cuenta, su presencia en nuestro día a día, disfrutamos del azul horizonte que nos proporciona y de su oferta como lugar de encuentro y espacio de ocio. El contacto con el mar, el acceso físico a este medio nos despierta curiosidad, nos empuja a su conocimiento y por tanto a la conciencia de mantener una relación sostenible. Es en este sentido donde el acceso al océano acontece el acceso a su conocimiento, aspecto de importancia capital para nuestro desarrollo y para el futuro de nuestra existencia, y uno de los 7 objetivos –“el Océano accesible”– a lograr en la Década que celebramos. […], [CAT] Tots aquells que tenim la sort de viure vora el mar hem incorporat, sense adonar-nos, la seva presència en el nostre dia a dia, gaudim del blau horitzó que ens proporciona i de la seva oferta com a lloc de trobada i espai de lleure. El contacte amb el mar, l’accés físic a aquest medi ens desperta curiositat, ens empeny al seu coneixement i per tant a la consciència de mantenir-hi una relació sostenible. És en aquest sentit on l’accés a l’oceà esdevé l’accés al seu coneixement, aspecte d’importància cabdal pel nostre desenvolupament i pel futur de la nostra existència, i un dels 7 objectius –“l’Oceà accessible”– a assolir en la Dècada que celebrem. […]

Scientific research priorities and the need for assessing the marine environmental status and appropriately manage natural resources have encouraged the development of multidisciplinary and a wide range of observing capabilities, ranging from discrete in situ sampling to the use of large scale satellite remote sensing. In addition, long-term efforts have been made by the EU as well as by international organisations (EMODnet, Copernicus, OBIS, IODE, Reef Check ¿) to collect, harmonise and make data and information available to different types of end-users. However, due to the complex and rapidly changing dynamics of marine ecosystems, current monitoring procedures in the Mediterranean need to be revised to address current and most urgent environmental threats. The Interreg Med project SHAREMED (Sharing and enhancing capabilities to address environmental threats in the Mediterranean Sea) organized a virtual workshop aimed to share knowledge on the state of the art of observation systems and to identify the main environmental threats in the Mediterranean Sea. Leading representatives of major international projects and initiatives in marine observation systems and relevant to address the main environmental threats the Mediterranean Sea participated in the workshop. Also, a wide range of stakeholders (research institutions, national, regional and local authorities, NGOs) across the Mediterranean region attended the online workshop while others were contributed through a SHAREMED online survey. The information gathered helped to compare data and information available from current observation systems with the needs to address present and future threats, and thus to identify and prioritise gaps that should be addressed in designing a future transnational joint observation system. The outcomes of the SHAREMED stakeholder consultation highlighted the need to improve, upgrade and integrate physical, biological and chemical observations and assessment systems to cover from high

The encountering of the subtropical Brazil Current (BC) and the subantarctic Malvinas Current (MC) along the western margin of the Argentine Basin forms the Brazil-Malvinas Confluence (BMC), one of the most intense open-ocean fronts in the world ocean and a site for the formation of intermediate water masses. Here, we provide a comprehensive description of the BMC based on physical and biogeochemical data – hydrographic stations, profiling floats and subsurface drifters – gathered in March 2015. We use these data in order to characterize the impinging and outflowing currents and to describe the cross- and along-frontal thermohaline structure. In addition, we compare the in-situ measurements with both climatological data and the Mercator Ocean eddy-resolving reanalysis. The hydrographic sections illustrate the contrasting properties between the two western boundary currents: warm, salty, nutrient- and oxygen-poor oligotrophic subtropical waters carried southward by the BC and the cold, fresh, oxygen- and nutrient-rich subantarctic waters carried northward by the MC. The frontal system is also characterized by the presence of thermohaline intrusions, with the cross-frontal gradients and along-front velocities sharpening as the colliding currents shape the frontal system. We also observe brackish waters spreading on top of the frontal jet as a result of both the confluence dynamics and off-shelf advection favored by north-easterly winds. These low-salinity waters are positively correlated with surface ageostrophic speeds over the frontal jet. The cruise data illustrates the high regional and mesoscale variability as compared with climatological conditions, and further document the submesoscale subsurface complexity, which is not properly captured by available operational models