48th Liège Colloquium: Submesoscale Processes. Mechanisms, Implications and New Frontiers, 23-27 May 2016, Liège, Belgium.-- 1 page, 7 figures, The Brazil-Malvinas Confluence (BMC), the encountering site of waters of subtropical and subantarctic origin, is one of the most energetic regions in the world ocean. During March 2015, the R/V Hespérides carried out the TIC-MOC cruise, with 14 days of measurements in the BMC region. Field and remote-sensing data collected during the TIC-MOC cruise clearly illustrate the presence of mesoscale and submesoscale structures of different sort on top of the very energetic large-scale Brazil and Malvinas Currents. These two meridional currents, each of the order of 100 km wide, collide frontally before diverting east, leaving behind vortices of opposite sign near the collision region, but also much farther away, as well as multiple submesoscale structures. Here we characterize the spatial structure of the two colliding currents and of three (one cyclone and two anti-cyclones) vortices found in the near field (at distances less than 500 km from the collision point). We use the satellite images to identify several submesoscalar structures at the frontal system and in the margins of both the main currents and the mesoscalar structures. We also employ high resolution field data to study two different types of submesoscale structures observed in the frontal system. These are a very shallow (5-20 m), thin (5-50 km) and intense (velocities close to 2 m s-1) filament that flows east over the frontal system, carrying brackish waters from Rio de la Plata, and a number of relatively small thermohaline intrusions (thickness 10-100 m and width of the order of 10 km) that intrude several tens of km into both sides of the frontal system. An energy analysis of the frontal system shows that the flux of kinetic energy into the confluence region,associated with the two large scale currents,is of the order of 10 GW while the mesoscalar structures in the near field contain some 107-108 GJ of kinetic energy, giving a residence time of the order of 10-100 days. While some of these mesoscalar structures may flow away from the BMC region during these time intervals, others remain in the area for longer periods, hence requiring substantial energy transfer from the meso- to the submesoscale, This work has been supported through projects TIC-MOC (ref. CTM 2011-28867) and VA-DE-RETRO (ref. CTM2014-56987-P) of the R+D Spanish national program. DOE was supported by a pre-doctoral fellowship (ref. FPU13/02884) from the Spanish Ministry of Education, Peer Reviewed

2016 Ocean Sciences Meeting, 21-26 February 2016, New Orleans.-- 1 page, 7 figures, The Inter-Tropical Convergence Zone (ITCZ) oscillates seasonally in the North Atlantic Ocean, its mean position moving between the Equator in February and 10°N in August-September. Further, during its annual march, the ITCZ remains oriented SW-NE, with 10° of latitude difference across the Atlantic. As a consequence, Ekman convergence-divergence changes zonally and seasonally, setting up the sea-surface absolute dynamic topography (ADT) that drives geostrophic currents in the tropical ocean and the adjacent subtropical gyres. The clearest example is the seasonal growth of the North Equatorial Counter Current (NECC) at 6-8°N, as an intense eastward jet in the tropical North Atlantic amid the westward South Equatorial Current (SEC). The NECC starts in the eastern Atlantic in May and progresses west, fed by a northern diversion of the SEC, until it reaches the western boundary in August, causing the retroflection of the North Brazil Current (NBC). The NECC results from the boreal-summer northward penetration of the ITCZ and the associated South Atlantic High: the surface winds cause zonal bands of meridional Ekman convergence (3-7°N) and divergence (7-13°N) that lead to a ridge-valley ADT pattern, with the NECC unfolding at those latitudes of large latitudinal ADT gradients (6-8°N). The NECC intensifies through input from the interior gyres - anticyclonic near the low-latitude ridge and cyclonic around the northern valley, the latter related to the northern subtropical cell - and only after August it fuels from the NBC retroflection. The northern position of the ITCZ prevents analogous jets and retroflections to occur in the southern hemisphere, yet the location where the SEC bifurcates (into the northward NBC and the southward Brazil Current) changes between January (8°S) and June (16°S). Further, between April and July, a ridge-valley ADT distribution appears in the western tropical South Atlantic, giving rise to cyclonic-anticyclonic motions near 12°S-6°S. Here we (1) integrate recent work on the tropical Atlantic, (2) examine several types of observational and numerical data, and (3) use an idealized wind-driven model for the surface ocean, in order to stress the relevance of the ITCZ motion on both the surface circulation patterns and the net latitudinal transport in the tropical and subtropical Atlantic, This research has been supported by the Spanish government through the TIC-MOC (CTM2011- from the ECCO2 model, and (right) at (5.5S, 34W), as inferred from the 200-m climatological outputs from the ECCO2 model. The color bar represents days before 28867) and VA-DE-RETRO (CTM2014-56987-P) projects, Peer Reviewed

Emelianov, Mikhail ... et al.-- IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 2 pages, 1 figure, La Confluencia de Brasil-Malvinas (CBM), donde confluyen las masas de agua de origen subtropical (Corriente de Brasil) y subantártico (Corriente de Malvinas), juega un papel clave en la transferencia meridional de masa, calor y sal, como parte del ramal de retorno de la cinta transbordadora global en el Océano Atlántico. En marzo de 2015 se realizó a bordo del BIO Hespérides la campaña TIC-MOC, con el fin de caracterizar las condiciones oceanográficas en la región de la BMC. Durante la campaña se hicieron 66 estaciones hidrográficas y se lanzaron 8 flotadores y 9 perfiladores de deriva, en lo que resultó ser un muestreo de alta resolución espacio-temporal de los procesos que se desarrollan en la Confluencia a distintas escalas. Las observaciones revelan la colisión frontal de las dos corrientes, cada una de ellas con altas velocidades, que en superficie pueden exceder 1 m s-1. Este choque crea un complejo sistema frontal, con elevados gradientes horizontales de variables físicas y biogeoquímicas, que está caracterizado por intrusiones termohalinas y remolinos de ambos signos, además de un filamento superficial que se extiende hacia el este con velocidades cercanas a 2 m s-1, Este trabajo ha sido posible gracias a la financiación del Ministerio de Economía y Competitividad del gobierno de España, a través de los proyectos TIC-MOC (CTM2011-28867) y VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 2 pages, 2 figures, Recent studies have shown that sea surface temperature (SST) and surface wind speed (SWS) are directly related at ocean mesoscales (10-100 km). Here we examine this relationship in the Brazil-Malvinas Confluence region, where we find one of the most intense regional-scale SST gradients in the world's oceans. We analyze SST and SWS collected in situ during an oceanographic cruise done in March 2015. Data is processed to emphasize the variability of SST and SWS associated with oceanic fronts, both at regional and mesoscalar scales, taking into account the latitudinal SST gradients, the passage of atmospheric synoptic disturbances, and the diurnal variability of SWS. We observe that SST has an influence on SWS - a temperature raise of 1ºC involves a wind-speed increase of 0.36 m s-1, with a correlation coefficient of 0.43 and a 95% confidence level - a relationship that is corroborated using wind data from the European Copernicus Project. Finally, we assess the influence of SST on the lower atmosphere through the changes in sensible and latent heat fluxes across the front. The results point at the existence of significant coupling between the upper ocean and the lower atmosphere, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through projects TIC-MOC (CTM2011-28867) and VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 2 pages, 2 figures, 1 table, The Brazil Current (BC) and the Malvinas Current (MC) meet at the Brazil-Malvinas Confluence (BMC) region. This encounter is characterized by a complex mesoscale structure, with numerous eddies, filaments and thermohaline intrusions that lead to meridional exchange of mass, heat and salt between both currents. Therefore, the BMC is the site where the subtropical gyre and the ACC exchange key properties, thus playing a fundamental role in the Earth's climate. During March 2015, the R/V Hespérides carried out the TIC-MOC cruise in the BMC with the objective of sampling the BMC with high resolution. Here we use 28 hydrographic sections from this cruise that, together with the South American coast, constitute a closed ocean volume with sides about 400 km, and build an inverse box model to quantify the mass exchange through its contour. We find that mass enters the region predominantly from the north, carried by the BC, and leave through the eastern section; most of the flow from the south also leaves the region through the southern boundary. The results are consistent with the velocity field as measured during the cruise, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through projects TIC-MOC (CTM2011-28867) and VA-DE-RETRO (CTM2014-56987-P). Dorleta Orue-Echeverría has been funded through a FPU contract of the Ministerio de Educación y Ciencia, Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 2 pages, 2 figues, The Earth's climate is the outcome of numerous feedback energetic mechanisms. Paleoclimatic data tells us that the Earth has shifted between glacial and interglacial periods during the last 3 Myr, alternating between different temperature and atmospheric-CO2 states. Variations in key global processes are responsible for these transitions: CO2 atmospheric concentration, incoming solar radiation, meridional overturning circulation and albedo. Here we propose two simple box-models in order to analyze the effect of these processes on the heat content of the atmosphere and the upper-ocean during the last 450 kyr. The simplest model has only three boxes: atmosphere, upper-ocean and deep-ocean. The atmosphere and upper-ocean are allowed to exchange heat while the upper and deep oceans are connected through the meridional overturning circulation (MOC); it allows assessing the effects of cloud cover, greenhouse gases and MOC on climate but presents several important limitations, e.g. in the absence of a cooling mechanism, the deep ocean would warm up in times scales of order 10 kyr. Hence, we move to a more realistic five-box model, distinguishing now between high- and low-latitude atmospheric and upper-ocean compartments. This model, which adequately reproduces current estimates of preindustrial temperatures and heat fluxes, is used to estimate how these variables changed during glacial periods. Most important, the model helps us assess the relevance of the different physical processes on the Earth's climate, such as the latitudinal exchange within the ocean and atmospheric compartments, the intensity of the MOC and the reflecting power of albedo at high latitudes, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P). Dorleta Orúe-Echeverría has been funded through a FPU contract of the Ministerio de Educación y Ciencia, Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 1 page, 1 figure, Temperature-salinity (T-S) diagrams are widely used to spot the temperature (T) and salinity (S) relations at different places and times. They also help visualize how water masses with different T and S values mix up as they propagate away from the formation regions. Potential density (rho) is typically included in these diagrams to emphasize the vertical stability of a given hydrographic cast or to illustrate how two water masses remain at different density levels. Alternatively, we may introduce a new variable that sets a surrogate orthonormal space, with rho on one axis and spiciness (pi) on the other (Flament, 2002; but see Veronis, 1972, and Jackett and McDougall, 1985). Here we discuss how the rho and pi anomalies in this space may be interpreted as latent diapycnal and epipycnal mixing, or mixing yet feasible to take place, between two water masses. We illustrate these concepts with casts that sample the Mediterranean Outflow (MO) running under the North Atlantic Central Waters (NACW) stratum in the eastern Gulf of Cádiz (Fig. 1), This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 2 pages, 2 figures, El objetivo del estudio es validar un modelo regional tridimensional que simula la salida de agua mediterránea desde el Estrecho de Gibraltar hacia el Golfo de Cádiz en la época actual. Este modelo está únicamente forzado por la diferencia de densidad existente entre dos aguas tipo idealizadas: agua Atlántica y Mediterránea. La densidad de cada tipo de agua está definida por los correspondientes perfiles de temperatura y salinidad. Mediante la diferente carga hidráulica en el Estrecho, se estudia el ajuste en profundidad del agua mediterránea en su salida desde el Estrecho de Gibraltar hacia la cuenca Atlántica, Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad del gobierno de España a través de los proyectos TIC-MOC (CTM2011-28867) y VA-DE-RETRO (CTM2014-56987-P). Durante la realización de este trabajo, Sergio Ramírez Garrido ha tenido un contrato FPI del Ministerio de Economía y Competitividad vinculado al proyecto TIC-MOC (CTM2011-28867), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 2 pages, 2 figures, Un modelo oceánico de cajas, al que se imponen condiciones de conservación de energía interna, de salinidad y de masa, permite establecer (a) en que escenarios se forma agua de mayor densidad en la alta latitud norte, en lo que denominamos situación de estuario inverso o negativo (flujo en sentido norte-sur por el fondo oceánico), y (b) en que otros escenarios dicha formación se produce en las latitudes tropicales, en lo que sería un estuario directo o positivo. Se contrastan los escenarios resultantes a la vista de las condiciones del océano actual, JLP agradece el apoyo recibido por parte del Ministerio de Economía y Competitividad del gobierno de España a través del proyecto VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 1 page, 1 figure, Maps of velocity vectors and streamlines, calculated after integration from some reference contour, can be very useful to illustrate the gross characteristics of the changing velocities. Nevertheless, they are only snapshots of the velocity field that cannot be used to directly infer exchange between different oceanic regions. In order to do so, we must use of a Lagrangian approach, where we actually track water parcels as they move under the influence of the spatially and temporally changing velocity fields. Here we present a simple model that integrates monthly velocity fields in time, either forward or backward, in order to track the origin or fate of water parcels. In our case, the velocity fields are inferred from the positions of Argo floats. We illustrate the model by examining the recirculation of intermediate waters in the southern South Atlantic Ocean. The model allows us tracking whether and how the water parcels at these intermediate depths recirculate zonally or drift meridionally. In this application, we carefully explore the important role of the Brazil-Malvinas Confluence and the Agulhas Leakage. We estimate that most of the intermediate waters recirculate across the ocean in time periods between about 15 and 30 years, eventually meeting at the Brazil-Malvinas Confluence region. Our results show no water transfer from the Indian Ocean, i.e. they show no Agulhas Leakage, although this may be an artefact caused by the absence of rings in the mean fields. A remarkable feature is the presence of a meridionally pulsating behaviour in the transoceanic trajectories, best visible in an accompanying video, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante,España.-- 1 page, 1 figure, Since 2007, in the world's oceans there are over 3000 Argo floats that transmit position data typically once every 10 days. This represents some 100.000 positions yearly that lead to an equivalent number of velocity vectors. This massive amount of velocity data allows us constructing monthly-mean fields with spatial resolution of the order of 1º in latitude-longitude. Here we present, for the first time, the monthly sea-surface velocity fields for all oceans, unravelling the spatial distribution of the seasonally evolving fields. The velocity fields are predominantly zonal except for the western boundary subtropical regions. Further, these zonal fields change spatially following the evolution of the Intertropical Convergence Zone and the accompanying low- and high-pressure centres in both hemispheres. The resulting patterns appear as a transoceanic meridional seasonal pulse, typically propagating from south to north and from east to west. This work illustrates the potential of the Argo-inferred velocity data for an improved description of the surface currents at regional and, most remarkably, global scales, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

IV Encuentro Oceanografía Física Española, celebrado del 20 al 22 de julio de 2016 en Alicante, España.-- 3 pages, 1 figure, Satellite-tracked drifting buoys are useful for sampling sea-surface currents. Standard drifting buoys have drogues centred at a depth of 15 m, a fundamental element that guarantees that the direct wind force on the buoy is much smaller than the drag on the anchor. When a drifter loses its drogue, it no longer becomes a good tracker of the surface currents, hence the relevance of identifying when this happens. Here we propose a spectral-based approach to analyse drifter velocity data so as to detect when a drifter loses its drogue without the need of concurrent wind data. The method, applied to data obtained during the SPURS 2013 cruise, shows a substantial increase in the band-passed velocity energy at the time the drifter loses its drogue, as deduced with an independent method that considers the temporal change of the correlation between wind and positioning data. The results are very promising, pointing at a new method that can detect drogue loss from a relatively simple analysis of positioning data, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P). Ignasi Vallès has been funded through a FPI contract of the Ministerio de Competitividad y Economía. The drifter data was obtained following deployments during the SPURS cruise, in the frame of the MIDAS-6 (AYA2010-22062-C05-01) project, financed by the Ministerio de Economía y Competitividad of the Spanish Government, Peer Reviewed

Any ocean perturbation tends towards an equilibrium situation where the vertical balance is hydrostatic and the dominant horizontal forces are pressure gradients and Coriolis force, the so called geostrophic balance. Any motion that represents a desviation from this balance is named ageostrophic. At spatial and temporal scales of order 10-100 km (mesoscale) and longer, these desviations are small except within boundary layers related to the sea-surface wind stress and the sea-bottom friction. At shorter scales (submesoscale), however, they may represent a major part of the motion: these ageostrophic movements correspond to high Rossby values (the ratio of the inertial period, of order 1 day, and the advective time scale) and are usually accompanied by significant vertical motions.
The Brazil-Malvinas Confluence (BMC) region is located approximately 200-400 km offshore from Rio de la Plata, where the Brazil Current (BC) and Malvinas Current (MC) collide [1]. This clash leads to the generation of very energetic mesoscale and submesoscale features, as well as to different kinds of propagating waves. During March 2015, the R/V Hespérides sampled the BMC with several high resolution transects of the BMC frontal region (Figure 1), including velocity, temperature and salinity measurements (TIC-MOC cruise). These field data is complemented with data from satellites, the Argo program and the Copernicus operational model. Here we present the results of the data analysis, including the determination of vertical velocities as obtained solving the Omega equation. The BMC turns out to be a region with very energetic ageostrophic motions, characterized by a surface filament and subsurface thermohaline intrusions, as well as substantial vertical velocities, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through projects TIC-MOC (CTM2011-28867) and VA-DE- RETRO (CTM2014-56987-P), Peer Reviewed

6th Euro-Argo Users Meeting, 4-5 July 2017, Paris, France, Ten years ago we began deploying Argo drifters during regional cruises, and this has been repeated for several regions: the Canary and Cape Verde Basins, the western equatorial Atlantic and the Brazil-Malvinas Confluence (BMC). Suring a field experiment, several floats were deployed in different areas of the study region, such as in both sides of a frontal system. The floats were always simultaneous with a CTD cast whose data was immediately transmitted to the Euro-Argo centre. In all instances the floats provided additional data for characterizing the study area. Here we report on floats deployed during a recent cruise (RETRO-BMC) carried out in the BMC, between 8 and 28 April 2017 onboard the R/V Hespérides. The vessel departed from Ushuaia (Argentina) and arrived to Santos (Brazil). A total of 6 floats were deployed during the cruise, four of them in the frontal system itself and two of them in the Malvinas and Brazil Currents before arrival and after departing the BMC. Those floats deployed near the frontal system had a high-frequency cycling of once per day down to 2000 m during the first 20 days of operation, providing for a total of 80 additional CTD casts in the area of study, synoptic with the cruise CTD casts. These experiments are a good example of a highly beneficial synergetic effort of Euro-Argo and the research teams, VA-DE-RETRo CTM2014-56987-P, Peer Reviewed

V Encuentro de la Oceanografía Física (EOF 2018) - V Physical Oceanography Meeting, VI Simposio Internacional de Ciencias del Mar - VI International Symposium of Marine Sciences (ISMS 2018), 20- 22 June 2018, Vigo.-- 1 page, At temporal scales that range from years to hundreds of thousands of years, the Earth is the amazing outcome of the complex combination of its major ocean ecosystems. These subsystems develop in ocean regions with specific physical characteristics that result from both external forcing and large-scale ocean currents; there certainly are biological feedbacks but these are somewhat limited and not essential for the global system. Nevertheless, the microscopic plankton that develops within each of these regions will have properties that respond to the characteristic of the physical environment, setting up a regional ecosystem with special features. The strength of the emerging planetary complex system relies on the capacity of all these regional ecosystems to ensemble, to connect through large-scale ocean currents, each with a complementary role. This Earth system has certainly evolved along its paleo-history, adapting to tectonic and insolation changes, adjusting and modifying the role of each of its major ocean ecosystems to ensure the homeostatic equilibrium of the global system, remaining always near an optimized state. Humanity has – as if it was an environmental gene – the capacity of modifying the physical environment so that, once again, the currents and ecosystems will readjust for the benefit of the entire planetary organism, though very likely in detriment of the human race, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

V Encuentro de la Oceanografía Física (EOF 2018) - V Physical Oceanography Meeting, VI Simposio Internacional de Ciencias del Mar - VI International Symposium of Marine Sciences (ISMS 2018), 20- 22 June 2018, Vigo.-- 1 page, Using sea surface temperature variability and the definition of the BrazilCurrent and Subantarctic fronts in terms of dynamic height, we define an index for the Brazil-Malvinas front and calculate its location for the 1870-2016 period. With this new index, the seasonal cycle is studied. Also, changes in its temporal variability, including those associated with its meridional location and amplitude, are analysed. The results suggest multi-decadal modulations of the interannual variability in relation to changes in the position of the Intertropical Convergence Zone. The links with the variability of the Agulhas leakage and the westerly winds are also explored and discussed, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P). Dorleta Orúe-Echevarría has been funded through a FPU contract of the Ministerio de Educación y Ciencia, Peer Reviewed

V Encuentro de la Oceanografía Física (EOF 2018) - V Physical Oceanography Meeting, VI Simposio Internacional de Ciencias del Mar - VI International Symposium of Marine Sciences (ISMS 2018), 20- 22 June 2018, Vigo.-- 1 page, The large-scale temperature-salinity relationship is the result of numerous processes acting at many spatial and temporal scales. Here, we analyze the role of mesoscale isoneutral stirring and small-scale turbulence dianeutral stirring setting this relationship in the southwest Atlantic Ocean. We use hydrographic and microstructure data collected during the GEOTRACES 40S cruise, between the mid-Atlantic Ridge and the American coast along 40ºS in the framework of a triple decomposition (Garret, 2001; Ferrari and Polzin, 2005). The underlying premise is that large scale variance of potential temperature generated by these two mixing processes is dissipated by molecular processes. Dianeutral velocities are higher near the surface and the bottom layers, especially in those stations near the Mid-Atlantic Ridge or the Brazil Current Overshoot (BC-O) where values approach 10-4 m2 s-1; stations between those two features show the lowest values, of about 0.3 × 10-5 m2 s-1 for all layers. The range of isoneutral diffusivities span at least three orders of magnitude: 102 to 105 m2 s-1 being usually higher in the eastern than in the western BC-O flanks. In almost no layer or station the dianeutral production of temperature variance balances its dissipation, the latter usually being two or more orders of magnitude larger. Our results suggest that isoneutral production by mesoscale stirring is the main factor contributing to the variance production in this region, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through project VA-DE-RETRO (CTM2014-56987-P). Dorleta Orúe-Echevarría has been funded through a FPU contract of the Ministerio de Educación y Ciencia, Peer Reviewed

V Encuentro de la Oceanografía Física (EOF 2018) - V Physical Oceanography Meeting, VI Simposio Internacional de Ciencias del Mar - VI International Symposium of Marine Sciences (ISMS 2018), 20- 22 June 2018, Vigo.-- 1 page, Output of an eddy-resolving numerical experiment (1/12-degree resolution), forced with NCEP Reanalysis products from 1970 to 2010, has been found for studying the variations in the Agulhas System and their impact on the tropical Atlantic Ocean. That work has suggested that the increase of the Agulhas transport affects the western boundary system of the tropical Atlantic Ocean, which is directly related to an increase in the precipitation and latent heat flux along the western coast. Paralel to this, other studies have found how tropical Atlantic interanual variability modes have changed showing a westward extension in the configuration of the Atlantic Niño. Using the above-mentioned simulations, the present study tries to conciliate both results and to seed light about the impact of the Agulhas leakage in changes in the south Atlantic heat content and configuration of the oceanic interanual variability, This research has been supported by the Ministerio de Economía y Competitividad of the Spanish Government through projects VA-DE-RETRO (CTM2014-56987-P, Paola Castellanos) and Juan de la Cierva Incorporación Programme (IJCI-2015-26645, Teresa Losada Doval), Peer Reviewed

VII International Symposium on Marine Sciences (ISMS 2020), 1-3 July 2020 (Barcelona).-- 2 pages, Warm phases of the Atlantic Zonal Mode (AZM), known as Atlantic Niño (AN), are caused by a variety of mechanisms. In this study we analyze the diversity of AN-events through an inter-event empirical orthogonal function (EOF) methodology. The first two orthogonal modes, which explain 30% and 24% of the inter-annual variability, allow describing four of the principal spatio-temporal patterns in sea surface temperature (SST). The first two contrast the timing of dissipation (i.e., early-terminating versus persistent), while the other two the timing of onset (i.e., early-onset versus late-onset). Largely consistent with the differences in the timings of onset and dissipation, these four varieties display remarkable differences in rainfall response over West Africa and South America. Some are also subject to onset mechanisms that involve preconditioning in boreal spring from the Atlantic Meridional Mode or El Niño in the Pacific, while for others there is no clear source of external forcing, This work was supported by the Spanish Government funding through projects VA-DE-RETRO (CTM2014-56987-P) and SAGA (RTU2018-100844-B-C33), and by NOAA’s Climate Program Office, Climate Variability and Predictability Program (award GC16-207) and NOAA/AOML. I.V.C. was funded through FPI contract (BES-2015-071314), Peer reviewed

VII Encuentro de Oceanografía Física (EOF) - Expanding Ocean Frontiers Conference, VIII International Symposium on Marine Sciences, 6-8 July 2022, Las Palmas de Gran Canaria, España, The northward warm North Brazil Current (NBC) in the western tropical Atlantic is the main cross-equatorial pathway of the Atlantic Meridional Overturning Circulation (AMOC). An important part is distributed through the recirculation pathways of the interior basin, which mostly take place through a complex retroflection system. The Equatorial Undercurrent (EUC) arise from the NBC retroflection at the equator transporting thermocline waters from the western to eastern equatorial Atlantic basin.
In this study we characterize this NBC-EUC retroflection with temperature, salinity and velocity data acquired in the framework of MOC2 oceanographic cruise in April 2010. Moreover, we expand our analysis by performing off-line Lagrangian modelling on the 3D velocity field form the ocean-reanalysis GLORYS2v4. From particle trajectories, and their associated transport, we reveal four main water sources and water mass transformations from tropical and subtropical North and South Atlantic regions that feed the NBC-EUC retroflection. The predominant water contribution changes as we shift between density classes and each one is dominated by distinct retroflection latitudinal pathway. Additionally, we describe the seasonal-to-interannual transport variability associated with the coupled ocean-atmosphere tropical Atlantic system. Outstandingly, we show a transport increase of tropical South Atlantic waters from 2008 onwards consistent with the recently reported Subtropical Cells (STCs) intensification, This work has been funded by the Spanish Government through project VADERETRO (Ministerio de Economia y Competitividad, ref. no. CTM2014-56987-P), SAGA (Ministerio de Ciencia, Innovacion y Universidades, ref. no. RTI2018-100844-B-C33) and supported by the Israeli Science Foundation grant 1022/21, Peer reviewed