Special issue Economics of Bioenergy 2015.-- 36 pages, 1 figure, 6 tables, 9 appendix, A feasible way to avoid the risk of energy decline and combat climate change is to build a 100% renewable global energy mix. However, a globally electrified economy cannot grow much above 12 electric terawatts without putting pressure on the limits of finite mineral reserves. Here we analyze whether 12 TW of electricity and 1 TW of biomass (final) power will be able to fuel a future post-carbon economy that can provide similar services to those of a contemporary economy. Contrarily to some pessimistic expectations, this analysis shows that the principle economic processes can be replaced with sustainable alternatives based on electricity, charcoal, biogas and hydrogen. Furthermore, those services that cannot be replaced are not as crucial so as to cause a return to a pre-industrial society. Even so, land transport and aviation are at the limit of what is sustainable, outdoor work should be reorganized, metal primary production should be based on hydrogen reduction when possible, mineral production should be increasingly based on recycling, the petrochemical industry should shrink to a size of 40%–43% of the 2012 petrochemical sector, i.e., a size similar to that the sector had in 1985–1986, and agriculture may require organic farming methods to be sustainable., This work has been partially supported through the project “Vade Retro” (CTM2014-56987-P) of the Research and Development Spanish program. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI), We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)., Peer Reviewed

28 pages, 13 figures, 3 appendix, The steady flow of three-dimensional isolated axisymmetric baroclinic geophysical vortices in cyclo-geostrophic and hydrostatic balance with spheroidal pressure anomaly gradients is investigated through the analysis of three-parameter vortex families. The vortices have an inner core in near solid-body rotation and zero, or negligibly small, pressure anomaly gradient at the vortex boundary. Thus, these isolated vortices have zero amount of potential vorticity anomaly. As the vortex amplitude parameter a1 is increased in cyclones, static instability at some depth along the vortex vertical axis is reached before centrifugal instability occurs at the minimum of negative vertical vorticity at the surface vortex outer core. In anticyclones, as |a1| increases, centrifugal instability occurs before static instability at the vortex centre. The first vortex family analyzed, denoted V(p,q), is characterized by spheroidal pressure anomaly gradients F′(p,q;x) such that the first ⌊p⌋ (integer part of p) derivatives of F′′(p,q;x) at the vortex centre x=0, and the first ⌊q⌋ derivatives of F(p, q; x) at the vortex boundary x=1 are zero. For comparison purposes two other three-parameter vortex families are introduced, namely the exponential E and the hyperbolic tangent H vortex families. The relation between the parameter values in each vortex family leading to statically stable vortices is provided. The main static instability properties of the three vortex families are similar, but each vortex family has their own qualities which make them more or less appropriate to a particular application, Partial support for this research has come from the Spanish Ministerio de Economía y Competividad (grant numbers CTM2011-2886 and CTM2014-56987-P), Peer Reviewed

Special volume: Planet Ocean. Scientia Marina 80(Suppl.1) 2016.-- 10 pages, 7 figures, [EN] In this work we report short-term measurements of the thermohaline structure and velocity field inside a narrow submarine canyon by means of a yo-yo–like profiler. An Aqualog profiler was deployed inside the Besòs Canyon in the northwestern Mediterranean continental margin, providing a unique data set on the vertical evolution of water column characteristics with unprecedented fine-scale spatial and temporal resolution. The observations reported here show a very dynamic transient short-term response with a complex vertical structure not observed previously in any submarine canyon of this region. The vertical distribution of water masses was characteristic of the western Mediterranean basin with Atlantic waters (AW) at the surface, Western Intermediate waters (WIW) in the middle and Levantine Intermediate (LIW) waters below. Turner angle and empirical orthogonal functions show that double-diffusive and isopycnal mixing are the main dominant processes at small scales. The interfaces of the three layers exhibit highly vertical excursions in relatively short times. At the surface, deepening of AW was observed, associated with flow intensification events. Deeper in the water column, within the submarine canyon confinement, the WIW-LIW interface uplifts about 100-150 m. These motions are associated with relatively up- and down-canyon–enhanced current events (up to 15-20 cm s–1 at 500 and 800 m depths) along the canyon axis. The time scales of the vertical variability were concentrated in a broad band around the semi-diurnal and local inertial frequencies within the WIW and LIW layers, [ES] En este trabajo se muestran medidas a corto plazo de la estructura termohalina y del campo de velocidad dentro de un estrecho cañón submarino a través de un perfilador tipo yo-yo. Este perfilador Aqualog se desplegó dentro del cañón del Besòs en el noroeste del margen continental del Mediterráneo, proporcionando un conjunto de datos único sobre la evolución vertical de las características de la columna de agua, con una resolución espacial y temporal a escala fina sin precedentes. Las observaciones aportadas aquí muestran una respuesta de un periodo transitorio muy dinámico con una estructura vertical compleja no observada anteriormente en ningún cañón submarino de esta región. La distribución vertical de las masas de agua es característica de la cuenca mediterránea occidental con aguas del Atlántico (AW) en la superficie, aguas occidentales Intermedias (WIW) debajo de estas y aguas de Levante Intermedio (LIW) por debajo. Los ángulos de Turner calculados y sus EOFs muestran que la estabilidad a la difusión y mezcla isopicna son los principales procesos dominantes a escalas pequeñas. Las interfaces de las tres capas exhiben excursiones notablemente verticales en tiempos relativamente cortos. En la superficie, la profundización de AW se observó asociada a eventos de intensificación del flujo. A más profundidad en la columna de agua, dentro del régimen de cañón submarino, la interfase WIW-LIW se eleva unos 100-150 m. Tales movimientos se asocian al flujo de agua hacia arriba y hacia abajo del cañón (hasta 15-20 cm s–1 a 500 y 800 m de profundidad) a lo largo del eje del cañón. Las escalas de tiempo de variabilidad vertical aparecen concentradas en una amplia banda de frecuencias alrededor de los periodos inerciales semidiurnos y locales dentro de las capas WIW y LIW, This work was supported by the projects VA-DE-RETRO (CTM2014-56987-P), funded by the Spanish government. EU funded J.S. through the project Marine-Vectors (FP7-KBBE 266445). J.S. also acknowledges a CSIC JAE-Doc contract co-funded by the ESF, Peer Reviewed

Special volume: Planet Ocean. Scientia Marina 80(Suppl.1) 2016.-- 10 pages, 8 figures, 1 table, [EN] Mediterranean Water lenses (meddies) in the eastern North Atlantic, north of the Canary Islands, appear to often have their salty and nutrient-poor core accompanied by relatively fresh and nutrient-rich waters on top. We describe several occurrences of freshwater halos and berets for meddies sampled north of the Canary Islands—with instrumented moorings, Argo floats and oceanographic cruises—and identify the source of these fresh anomalies as diluted Antarctic Intermediate Water (AAIW). We propose that this capping takes place off Northwest Africa, as the southward-advected meddy interacts with the northward-advected AAIW. This interpretation is consistent with a simple analysis of the relevant advective-diffusive time scales associated with the passage of meddies under a layer of AAIW, and suggests that meddies may be a mechanism for AAIW export far into the North Atlantic Ocean, [ES] Los Meddies en el Atlántico Norte oriental, al norte de las Islas Canarias, a menudo parecen tener su núcleo salado y pobre en nutrientes acompañado de aguas relativamente frescas y ricas en nutrientes en la parte superior. Se describen varios casos de halos y boinas de agua dulce para meddies muestreados al norte de las Islas Canarias -con instrumentos anclados, perfiladores Argo y campañas oceanográficas- identificando así el origen de estas anomalías frescas como Agua Intermedia Antártica (AIAA) diluida. Proponemos que esta interacción se lleva a cabo en el noroeste de África, cuando el meddy advectado hacia el sur interactúa con el AIAA advectada hacia el norte. Esta interpretación es coherente con un simple análisis de las escalas de tiempo advectivo-difusivas asociadas con el paso de meddies bajo una capa de AIAA, y sugiere que los meddies pueden ser un mecanismo para exportar AIAA hacia el océano interior en el Atlántico Norte, This work was supported by the projects CANOA (CTM2005-00444/MAR), TIC-MOC (CTM2011-28867) and VA-DE-RETRO (CTM2014-56987-P), funded by the Spanish government. [...] FM was partly supported by the Spanish Ministry of Education and Science through the Juan de la Cierva Programme, Peer Reviewed

Special volume: Planet Ocean. Scientia Marina 80(Suppl.1) 2016.-- 14 pages, 7 figures, 4 appendixes, [EN] Offshore wind is proposed as an energy source to upwell nutrient-rich deep water to the ocean photic layers. A spar-buoy wind turbine with a rigid tube about 300 m long is proposed as a pipe to drive deep water up to the surface. The minimum energy required to uplift the water is the potential energy difference between surface waters inside and outside the pipe, which depends on the background density profile. The corresponding surface jump or hydraulic head, h, calculated for several analytical and experimental density profiles, is of the order of 10 cm. If the complete turbine power (of the order of several MW) is used for raising the water (assuming a 100% pump efficiency), in a frictionless flow, very large water volumes, of the order of thousands of m3 s−1, will be transported to the photic layers. In a more realistic case, taking into account pipe friction in wide pipes, of the order of 10 m radius, and a power delivered to the fluid of 1 MW, the volume transport is still very large, about 500 m3 s−1. However, such a large amount of dense water could sink fast to aphotic layers due to vertical static instability (the fountain effect), ruining the enhancement of primary production. Hence, some ways to increase the turbulent entrainment and avoid the fountain effect are proposed. From the energetic viewpoint, artificial upwelling using offshore wind energy is a promising way to fertilize large open sea regions. This mariculture application is, however, severely subjected to atmosphere and ocean climatology, as well as to ecological dynamics. The general problem is multidisciplinary, and some important physical, engineering and ecological questions need to be seriously addressed to improve our confidence in the approach presented here, [ES] Analizamos el uso de la energía eólica marina como fuente de energía para aflorar aguas profundas ricas en nutrientes a las capas fóticas del océano. Una turbina de viento tipo boya-pértiga, con un tubo rígido de unos 300 m de largo, se propone para transportar las aguas profundas hasta la superficie. La energía mínima necesaria para elevar el agua es la diferencia de energa potencial entre las aguas superficiales dentro y fuera de la tubería, que depende del perfil de densidad de fondo. El salto superficial de agua, o cabezal hidráulico h, calculado para varios perfiles analíticos y experimentales de densidad, resulta ser del orden de 10 cm. Si la potencia total de la turbina (del orden de varios MW) se utiliza para elevar el agua (suponiendo una eficiencia de la bomba del 100%), en un flujo sin fricción, el transporte de volumen de agua transportado a las capas fóticas es muy elevado, del orden de miles de m3 s−1. En un caso más realista, teniendo en cuenta la fricción en tuberías de un ancho del orden de 10 m radio, y una potencia proporcionada al fluido de 1 MW, el transporte volumen sigue siendo muy grande, de alrededor de 500 m3 s−1. Sin embargo, una cantidad tan grande de agua densa podría hundirse rápidamente a las capas afóticas debido a la inestabilidad estática vertical (efecto fuente) arruinando la mejora de la producción primaria. Por lo tanto se proponen algunas maneras de aumentar el arrastre turbulento y evitar el efecto fuente. Desde el punto de vista energético, el afloramiento artificial utilizando energía eólica marina parece una manera prometedora de fertilización de grandes regiones del mar abierto. Esta aplicación de maricultura, sin embargo, depende severamente de la climatología atmosférica y océanica, así como de la dinámica ecológica. El problema global es multidisciplinar, y algunos aspectos importantes de física, ingeniería, y ecología tienen que ser mejor estudiados para poder aumentar nuestra confianza en el método aquí presentado, Partial support for this study was obtained through projects CTM2011-28867 and CTM2014-56987-P (Spanish Ministry of Science and Innovation), Peer Reviewed

Special volume: Planet Ocean. Scientia Marina 80(Suppl.1) 2016.-- 12 pages, 4 tables, [EN] A feasible way to avoid the risk of energy decline and to combat climate change is to build a worldwide, 100% renewable energy mix. Renewable energy can be scaled up to the range of 12 electric terawatts (TWe) if 10% of continental shelves are exploited with floating turbines to depths as low as 225 m, 5% of continents with ground turbines, and 5% of the main deserts with concentrating solar power (CSP) farms. However, a globally electrified economy cannot grow much above 12 TWe without approaching the limit of terrestrial copper reserves. New photovoltaic silicon panels do not use silver metallization pastes and could contribute up to 1 TW of decentralized residential power. Hydroelectricity has a potential of 1 TW but a fraction of this would have to be sacrificed for energy storage purposes. Hydro, CSP, wave energy and grid integration at continental scales may be sufficient to fit supply to demand, avoiding intermittency. The renewable energy mix would have an energy return on energy invested about 18, which is 25% lower than the estimated present one. That should be sufficient to sustain an industrialized economy provided that the substitution of electricity for fossil fuels is done intelligently, [ES] Una forma posible de evitar el riesgo de declive energético y luchar contra el cambio climático sería construir un sistema energético global 100% renovable. Un sistema de energía renovable (ER) se podría escalar hasta el rango de 12 terawatios de electricidad (TWe) si el 10% de las plataformas continentales fueran explotadas con molinos flotantes hasta profundidades de unos 225 m, 5% de los continentes con turbinas terrestres, y el 5% de los principales desiertos fueran utilizados para estaciones de concentración solar (CSP). Sin embargo, una economía electrificada a nivel mundial no puede crecer muy por encima de 12 TWE sin acercarse al límite de las reservas globales de cobre. Los paneles fotovoltaicos (PV) de silicio más recientes no utilizan metalizaciones de plata y podrían contribuir con hasta 1 TW de energía residencial descentralizada. La hidroelectricidad tiene un potencial de 1 TW aunque una fracción de ello tendría que ser sacrificado con fines de almacenamiento de energía. Hidroelectricidad, CSP, energía de las olas y redes integradas de escala continental pueden ser suficientes para ajustar la oferta a la demanda, evitando la intermitencia. El nuevo mix eléctrico tendría una Tasa de Retorno Energético (TRE) de alrededor de 18, un 25% menos que la TRE actual estimada. Eso debería ser suficiente para sostener una economía industrializada, siempre que la sustitución de los combustibles fósiles por electricidad se haga de forma inteligente, This Work has been partially supported by projects “TIC-MOC”, ref. No. CTM2011-28867 and “VA-DE-RETRO”, ref. No. CTM2014-56987-P, financed by the Ministerio de Economía y Competitividad, from the Spanish National Research Programme, Peer Reviewed

18 pages, 13 figures, 2 tables, 1 appendix supplemental material https://dx.doi.org/10.1016/j.dsr.2016.10.003-- Data Availability: DIGITAL.CSIC https://doi.org/10.20350/digitalCSIC/18158; https://doi.org/10.20350/digitalCSIC/18295, We explore the associations between larval fish assemblages and oceanographic conditions in the upper ocean (top 200 m) along the African slope, from tropical (15°N) to subtropical (35°N) latitudes, during a period of intense upwelling. In this extensive region, the northward Mauritanian Current and Poleward Undercurrent carry South Atlantic Central Waters (SACW) while the southward Canary Upwelling Current transports North Atlantic Central Waters (NACW). South of Cape Blanc we only find SACW, and north of Cape Blanc there is NACW far offshore and a combination of NACW and SACW nearshore, separated by the Canary Upwelling Front (CUF). The larvae of different myctophid species serve as indicators of the water masses, e.g. S. veranyi and M. punctatum were found in some coastal stations that were dominated by NACW, while the tropical mesopelagic B. argyrogaster, H. macrochir, M. affine and S. kreffti were associated to the SACW. The along-slope offshore convergence of NACW and SACW takes place at the Cape Verde Frontal Zone (CVFZ), representing a region of extensive offshore export for larvae of coastal species, S. pilchardus and E. encrasicolus, far from their nearshore spawning area. The large-scale frontal systems (CVFZ and CUF) and mesoscale eddies contribute to retain larvae within productive waters, influencing both coastal and oceanic species, This research has been funded by the Spanish Ministerio de Ciencia e Innovacion through projects MOC2 (Reference no. CTM2008-06438-C02-01) and VA-DE-RETRO (Reference no. CTM2014-56987-P), Peer Reviewed

29 pages, 15 figures, 1 table, supporting information https://dx.doi.org/10.1002/2016JC012611, Horizontal and vertical motions associated with coherent mesoscale structures, including eddies and meanders, are responsible for significant global transports of many properties, including heat and mass. Mesoscale vertical fluxes also influence upper ocean biological productivity by mediating the supply of nutrients into the euphotic layer, with potential impacts on the global carbon cycle. The Brazil-Malvinas Confluence (BMC) is a western boundary current region in the South Atlantic with intense mesoscale activity. This region has an active role in the genesis and transformation of water masses and thus is a critical component of the Atlantic meridional overturning circulation. The collision between the Malvinas and Brazil Currents over the Patagonian shelf/slope creates an energetic front that translates offshore to form a vigorous eddy field. Recent improvements in gridded altimetric sea level anomaly fields allow us to track BMC mesoscale eddies with high spatial and temporal resolutions using an automated eddy tracker. We characterize the eddies across fourteen 5° × 5° subregions. Eddy-centric composites of tracers and geostrophic currents diagnosed from a global reanalysis of surface and in situ data reveal substantial subregional heterogeneity. The in situ data are also used to compute the evolving quasi-geostrophic vertical velocity (QG-ω) associated with each instantaneous eddy instance. The QG-ω eddy composites have the expected dipole patterns of alternating upwelling/downwelling, however, the magnitude and sign of azimuthally averaged vertical velocity varies among subregions. Maximum eddy values are found near fronts and sharp topographic gradients. In comparison with regional eddy composites, subregional composites provide refined information about mesoscale eddy heterogeneity, E.M. is supported by a postdoctoral grant from the Conselleria d'Educació, Cultura i Universitats del Govern de les Illes Balears (Mallorca, Spain) and the European Social Fund. S.R. and E.M. have been partially supported by the Copernicus Marine Environment Monitoring Service (CMEMS) MedSUB project. P.G. acknowledges the support of NASA grant NNX16AH9G and NSF grant OCE-1558809. J.L.P. wishes to acknowledge support from the VA-DE-RETRO project (CTM2014-56987-P) funded by the Spanish National Research Program. ACC frontal positions were provided by CTOH (http://ctoh.legos.obs-mip.fr). ARMOR3D data supplied by Copernicus Marine Environment Monitoring Service (CMEMS) at http://marine.copernicus.eu/. SRTM bathymetry data taken from http://topex.ucsd.edu/www_html/srtm30_plus.html, Peer Reviewed

12 pages, 6 figures, 2 appendixes, supplementary movies https://doi.org/10.1017/jfm.2017.440, Long-term marginal stability of a new family of isolated oceanic vortices is analysed. Sign reversal of the radial gradient of the potential vorticity anomaly, as implied by the isolation requirement, leads to vortex unsteadiness but does not break the coherence of the vortex, which remains marginally stable even for high absolute Rossby numbers . The marginally stable vortices are characterized by a zero amount of potential vorticity anomaly on every isopycnal. The marginally stable final state is an unsteady vortex whose inner one-signed potential vorticity anomaly experiences revolution, rotation, precession and nutation, Partial support for this study was obtained through project CTM2014-56987-P (Spanish Ministry of Science and Innovation), Peer Reviewed

17 pages, 12 figures, A South Atlantic ring is studied through remote sensing altimetry, hydrographic stations, and drifters' trajectories. The ring's core was characterized by warmer and saltier Indian Ocean waters. At the time of the cruise, the ring's signature extended radially out to 124 km and vertically down to 2000 m, and its core absolute dynamic topography (ADT) exceeded the surrounding Atlantic Ocean waters in 0.4 m. The geostrophic velocities were anticyclonic with maximum speeds about 35 cm s−1 at 100 m and reaching negligible values near 4500 m. The rotational transport inside the ring was 33 Sv in the thermocline and intermediate layers. The drifters' data distinguish a 30-km core revolving as a solid body with periodicity near 5 days and a transitional band that revolves with constant tangential velocity, resembling a Rankine vortex. The ADT data identify the ring's track, showing that it was shed by the Agulhas Current retroflection in November 2009 and propagated northwest rapidly during the first 2 months (mean speed of about 10 cm s−1) but slowed down substantially (3–4 cm s−1) between March and July 2010, when it was last detected. The altimetry data also outlines the evolution of the ring's core ADT, radius, vorticity, and, through a simple calibration with the cruise data, rotational transport. In particular, the ring surface and vertical-mean vorticity decay with time scales of 373 and 230 days, respectively, indicating that most of the property anomalies contained by the ring are diffused out to the subtropical gyre before it reaches the western boundary current system, This study has been performed as part of projects MOC2 (CTM2008-06438), VA-DE-RETRO (CTM2014-56987-P), and SeVaCan (CTM2013-48695) funded by the Spanish Government through the Ministerio de Economía y Competitividad, Peer Reviewed

Gasser, Marc ... et al.-- 25 pages, 19 figures, 1 table, supplementary material https://doi.org/10.1016/j.pocean.2017.05.015, The Mediterranean Water leaves the western end of the Strait of Gibraltar as a bottom wedge of salty and warm waters flowing down the continental slope. The salinity of the onset Mediterranean Outflow Water (MOW) is so high that leads to water much denser (initially in excess of 1.5 kg m¿3) than the overlying central waters. During much of its initial descent, the MOW retains large salinity anomalies ¿ causing density anomalies that induce its gravity current character ¿ and relatively high westward speeds ¿ causing a substantial Coriolis force over long portions of its course. We use hydrographic data from six cruises (a total of 1176 stations) plus velocity data from two cruises, together with high-resolution bathymetric data, to track the preferential MOW pathways from the Strait of Gibraltar into the western Gulf of Cadiz and to examine the relation of these pathways to the bottom topography. A methodology for tributary systems in drainage basins, modified to account for the Coriolis force, emphasizes the good agreement between the observed trajectories and those expected from a topographically-constrained flow. Both contour avenues and cross-slope channels are important and have complementary roles steering the MOW along the upper and middle continental slope before discharging as a neutrally buoyant flow into the western Gulf of Cadiz. Our results show that the interaction between bottom flow and topography sets the path and final equilibrium depths of the modern MOW. Furthermore, they support the hypothesis that, as a result of the high erosive power of the bottom flow and changes in bottom-water speed, the MOW pathways and mixing rates have changed in the geological past, This research has been carried out with the support of the Spanish government, through projects MOC2 (CTM2008-06438-C02-01), MED-OUTFLOW 2009 (CTM2008-03422-E/MAR), MED-OUTFLOW-2011 (CTM2010-11488-E) and VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

13 pages, 7 figures, 4 tables, supplementary material http://journals.ametsoc.org/doi/suppl/10.1175/JTECH-D-17-0090.1, The variability of a biogeochemical property in the ocean is the outcome of both nonconservative (such as respiration and photosynthesis) and conservative (mixing of water masses with distinct concentrations at origin) processes. One method to separate both contributions is based on a multiple regression of the biogeochemical property in terms of temperature θ and salinity S as conservative proxies of water masses. This regression delivers the variability related to the conservative fraction and hence allows for identifying the residual as the biogeochemical anomaly. Here, the standard multiple linear regression (MLR) method, which assumes that water masses mix locally and linearly, is compared with a nonlinear polynomial regression (PR) over the entire (θ, S) space. The PR method has two important advantages over MLR: allows for simultaneous nonlinear mixing of all water masses and does not require knowing the end-member water types. Both approaches are applied to data along 7.5°N in the equatorial Atlantic Ocean, and the biogeochemical anomalies are calculated for humic-like fluorescent dissolved organic matter, apparent oxygen utilization, and nitrate—all of them related through in situ remineralization processes. The goodness of both approaches is assessed by analyzing the linear dependence and the coefficient of correlation between the anomalies. The results show that the PR method can be applied over the entire water column and yet retains the local variability associated with nonconservative processes. The potential of the PR approach is also illustrated by calculating the oxygen–nitrate stoichiometric ratio for the entire 7.5°N transatlantic section, This research was supported by the Spanish government through projects MOC2 (CTM2008-06438-CO2) and VA-DE-RETRO (CTM2014-56987-P). Patricia De La Fuente would like to thank the Agència de Gestió d’Ajuts Universitaris i de Recerca de la Generalitat de Catalunya (AGAUR) for its financial support through an FI-AGAUR fellowship, Peer Reviewed

12 pages, 11 figures, supplementary data https://doi.org/10.1016/j.dynatmoce.2017.11.004, The interdecadal variability of the atmospheric and oceanic meridional overturning circulation is studied, using a coupled model with two narrow meridional barriers representing the land and a flat bottomed Aquaplanet. Empirical orthogonal function (EOF) analysis are used in the atmospheric and oceanic meridional overturning cells, revealing the atmospheric interdecadal variability is dominated by an annular mode, in both hemispheres, which introduces in the ocean a set of patterns of variability. The most energetic EOFs in the ocean are the barotropic responses from the annular mode. The interaction between the heat anomalies, due to the barotropic response, and the thermohaline circulation of each basin leads to a resonance mechanism that feeds back to the atmospheric forcing, modulating the annular mode spectrum. Besides the barotropic response, the annular mode introduces anomalies of salinity and temperature in the subtropical Atlantic that affects its upper buoyancy. These anomalies are incorporated within the ocean circulation and advected until the areas of deep sinking in the northern Atlantic, impacting on its overturning circulation as well, We are very grateful to the Brazilian National Council of Scientific and Technologic Development (CNPq) for the fellowship (140821/2013-9) and we want specially to acknowledge to the Vale Institute of Technology (ITV) for the financial and academic support to this project. The numerical experiments were conducted at the IO-USP Ocean Modeling Laboratory (LABMON) using computer resources funded by the São Paulo State Foundation for Research Support (FAPESP, Grants 2010/01943-8, and 2011/50552-4). Furthermore, the co-authors acknowledges the Brazilian National Council for Scientific and Technological Development (CNPq) for a Research Fellowship (Grant 302018/2014-0), and the support of the Spanish government, through project VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

23 pages, 9 figures, 3 tables, supporting information https://doi.org/10.1002/2017JC013509, Ventilation of the eastern South Pacific Oxygen Minimum Zone (ESP-OMZ) is quantified using climatological Argo and dissolved oxygen data, combined with reanalysis wind stress data. We (1) estimate all oxygen fluxes (advection and turbulent diffusion) ventilating this OMZ, (2) quantify for the first time the oxygen contribution from the subtropical versus the traditionally studied tropical-equatorial pathway, and (3) derive a refined annual-mean oxygen budget for the ESP-OMZ. In the upper OMZ layer, net oxygen supply is dominated by tropical-equatorial advection, with more than one-third of this supply upwelling into the Ekman layer through previously unevaluated vertical advection, within the overturning component of the regional Subtropical Cell (STC). Below the STC, at the OMZ's core, advection is weak and turbulent diffusion (isoneutral and dianeutral) accounts for 89% of the net oxygen supply, most of it coming from the oxygen-rich subtropical gyre. In the deep OMZ layer, net oxygen supply occurs only through turbulent diffusion and is dominated by the tropical-equatorial pathway. Considering the entire OMZ, net oxygen supply (3.84 ± 0.42 µmol kg yr) is dominated by isoneutral turbulent diffusion (56.5%, split into 32.3% of tropical-equatorial origin and 24.2% of subtropical origin), followed by isoneutral advection (32.0%, split into 27.6% of tropical-equatorial origin and 4.4% of subtropical origin) and dianeutral diffusion (11.5%). One-quarter (25.8%) of the net oxygen input escapes through dianeutral advection (most of it upwelling) and, assuming steady state, biological consumption is responsible for most of the oxygen loss (74.2%), P.J. Llanillo acknowledges support from CONICYT/FONDECYT through the Postdoctorado project 3150229. J.L. Pelegrí and J. Peña-Izquierdo acknowledge funding by the Spanish Ministerio de Economía y Competitividad through projects TIC-MOC (CTM2011-28867) and VA-DE-RETRO (CTM2014-56987-P), Peer Reviewed

13 pages, 10 figures, 2 tables, supporting information https://doi.org/10.1002/joc.5424, The role that the Indonesian Throughflow plays on climate is investigated in an alternative scenario, expected during glacial ages. The equatorwards shift of the Southern Hemisphere westerlies found in glacial ages acts to decrease the Agulhas Leakage (AL) and the thermohaline circulation (THC) in the Atlantic. Recent results suggest that these changes are followed by an increased THC in the Pacific, through an inter-basin seesaw mechanism. The enhanced circulation in the Pacific demands thermocline water to cross the equator towards northern latitudes, which shifts the water source of the throughflow from the low-salinity North Pacific to the relative saltier South Pacific. It is shown that in this equilibrium, the salinity anomalies of the throughflow impact the inter-basin seesaw towards the restoration of the modern climate, enhancing the North Atlantic Deep Water (NADW) formation and decreasing the THC in the Pacific. These results are consistent with paleo-observations and provide new insights to interpreting the climate changes in glacial periods., We are very grateful to the Brazilian National Council of Scientific and Technologic Development (CNPq) for the fellowship (140821/2013‐9) and we want specially to acknowledge to the Vale Institute of Technology (ITV) for the financial and academic support to this project. The numerical experiments were also a contribution to Projects SAMOC (grant 2011/5055‐4) and SANSAO (grant 2008/58101‐9), funded by the São Paulo State Foundation for Research Support (FAPESP). Furthermore, the co‐authors acknowledges the Brazilian National Council for Scientific and Technological Development (CNPq) for a Research Fellowship (grant 302018/2014‐0), and the support of the Spanish government, through project VA‐DE‐RETRO (CTM2014‐56987‐P), Peer Reviewed

18 pages, 13 figures, tables, 5 appendices, Two fundamental modes of vertical velocity (w) in mesoscale subsurface eddies are described using the quasigeostrophic (QG) approximation and nonhydrostatic numerical modeling. The first mode of w (the spheroidal mode) arises when a spheroidal upright subsurface eddy acquires horizontal eccentricity and becomes an ellipsoid, still upright, vertically symmetric vortex. In this case, the vertical displacement of isopycnals vanishes at the middepth z = 0. Conservation of potential vorticity anomaly (PVA) on elliptical concave/convex isopycnals entails a three‐dimensional octupolar pattern of w which also vanishes at z = 0. The second mode of w (the tilted mode) arises when the eddy remains spheroidal but its vertical axis tilts relative to the vertical direction. In this case, the displacement of isopycnals is largest at the middepth z = 0 and has a dipolar distribution. The associated w is largest at the middepth and develops also a dipolar pattern. In both spheroidal and tilted modes, the vertical velocity pattern may be inferred from the fast advection of PVA conserving fluid particles on slower translating concave/convex or tilted isopycnals. This implies that the vertical velocity of both modes is approximately QG and may be correctly inferred from the QG omega equation as long as the Rossby number remains small. Under more general circumstances, the vortex is both spheroidal and tilted. In this case, both spheroidal and tilted modes coexist but remain, to a large extent, uncoupled, rotating with different and, at least at a first order of approximation, constant phase speeds, Partial support for this study was obtained through project CTM2014-56987‐P (Spanish Ministry of Science and Innovation), Peer reviewed

12 pages, 3 figures, tables, 1 appendix, supplementary movies are available at https://doi.org/10.1017/jfm.2018.892, Exact solutions for multipolar azimuthal-mode vortices in two-dimensional Euler flows are presented. Flow solutions with non-vanishing far-field velocity are provided for any set of azimuthal wavenumbers m and arbitrary number n of vorticity shells. For azimuthal wavenumbers m=0 and m=1, the far-field velocity is a rigid motion and unsteady flow solutions with vanishing far-field velocity are obtained by means of a time-dependent change of reference frame. Addition of these first two modes, in the case of n = 1, results in a particular Chaplygin-Lamb (C-L) dipole, with continuous and vanishing vorticity at the vortex boundary. Numerical simulations suggest that this particular C-L dipole is stable, Partial support for this study was obtained through project CTM2014-56987-P (Spanish Ministry of Science and Innovation), Peer Reviewed

Orúe-Echevarría, Dorleta ... et al.-- 10 pages, 7 figures,4 tables, supplementary material https://doi.org/10.1016/j.dib.2018.12.004, This oceanographic dataset was gathered during the TIC-MOC cruise, which was designed to characterize the dynamics of the Brazil-Malvinas Confluence. The cruise was carried on board the R/V Hespérides, with departure from Ushuaia and arrival to Salvador de Bahía. A total of 66 conductivity-temperature-depth (CTD) stations were completed between 8 and 22 March 2015, offshore from the continental platform and within 45°S-35°S and 61°W-50°W. At each station, water samples were collected, which were used to calibrate the CTD salinity-oxygen sensors and to determine inorganic nutrient concentrations, and the horizontal current was measured. Along its track, the vessel recorded surface temperature and salinity, as well as the horizontal flow down to about 700 m. Lastly, eight position-transmitting drifters were launched and two profiling floats were deployed and later recovered, This research has been supported by the Spanish Government, through projects TIC-MOC (CTM2011-28867) and VA-DE-RETRO (CTM2014-56987-P) and through the funding of PhD scholarships for D.O.E. (FPU2013–02884), S.R.G. (BES-2012–055970) and C.H. (CSIC JAE-Predoc program), Peer Reviewed

28 pages, 17 figures, 4 tables, supporting information https://doi.org/10.1029/2018JC014733, The Brazil‐Malvinas Confluence arises from the frontal encountering of the subtropical Brazil Current and subantarctic Malvinas Current. It displays a complex regional circulation that is accompanied by mesoscale features and thermohaline intrusions. Here we combine altimetry and cruise data to describe the circulation pattern in the upper 2,000 m at two spatial scales encircling the frontal system. The major regional features appear south of the confluence latitude at 39–40°S: (a) a relatively weak Malvinas Current near 41°S, 56°W (28.3 ± 1.4 Sv), followed by its cyclonic retroflection; (b) an intense subtropical anticyclone (59.3 ± 10.7 Sv) that replaces the Brazil Current overshoot; and (c) a very intense subantarctic inflow (78.9 ± 13.7 Sv) near 53°W that is maintained through both an upstream (near 42°S) earlier diversion of the Malvinas Current and the cyclonic recirculation of the flow exiting east along the confluence. North of the confluence, the Brazil Current provides a net input of 30.8 ± 12.0 Sv (29.1 ± 8.3 Sv along the slope). The southern inflow splits nearly equal between barotropic and baroclinic contributions while the entire northern flow is essentially baroclinic. These northern and southern inputs add to an eastward along‐front transport of 109.7 ± 15.1 Sv, with significant contribution of highly oxygenated, relatively fresh Subantarctic Mode and Antarctic Intermediate Waters (58.7 ± 5.6 Sv). The regional circulation experiences substantial temporal variability, with southern waters flowing into the Brazil‐Malvinas Confluence through along‐slope and interior pathways and partly recirculating within the subtropical South Atlantic gyre, This research has been supported by the Spanish Government through projects TIC‐MOC (CTM2011‐28867) and VA‐DE‐RETRO (CTM2014‐56987‐P), and by RIS‐3, PO Feder Canarias through project BOUNDARY (ProID2017010083). Dorleta Orúe‐Echevarría has been funded through an FPU contract (ref. FPU2013‐02884)., Peer Reviewed

17 pages, 8 figures, supplementary material https://doi.org/10.3390/rs11070802, Three of the world’s most energetic regions are in the tropical and South Atlantic: the North Brazil Current Retroflection, the Brazil-Malvinas Confluence, and the Agulhas Current Retroflection. All three regions display offshore diversions of major boundary currents, which define the intensity of the returning limb of the Atlantic meridional overturning circulation. In this work, we use a sea-surface salinity (SSS) satellite product, combined with a high-resolution numerical model and in situ measurements, in order to explore the seasonal variation of the surface currents and transports in these three regions. The analysis of the model output shows that the SSS patterns reflect the surface velocity structure, with the largest horizontal SSS gradients coinciding with those areas of highest velocity and the most predominant velocity vector being 90° anticlockwise (clockwise) from the horizontal SSS gradient in the northern (southern) hemisphere. This information is then applied to the SSS satellite product to obtain maps of water velocity and salt transports, leading to a quantitative tool to estimate both water and salt transports in key regions of the world ocean, This work has been funded by the Spanish government through the National R+D Plan through projects VA-DE-RETRO (reference number CTM2014-56987-P), Promises (reference number ESP2015-67549-C3) and L-Band (reference number ESP2017-89463-C3-1-R). The HYCOM numerical experiment was supported by the São Paulo State Foundation for Research Support (FAPESP, Grants: 2008/58101-9, 2010/01943-8, and 2011/50552-4). E. Campos acknowledges the Brazilian National Council for Scientific and Technological Development (CNPq) for a Research Fellowship (Grant 302018/2014-0) and FAPESP (Grants, 2017/09659-6), We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

13 pages, 3 figures, 3 appendices, supplementary material https://dx.doi.org/10.1017/jfm.2019.234, An exact solution of a baroclinic three-dimensional vortex dipole in geophysical flows with constant background rotation and constant background stratification is provided under the quasi-geostrophic (QG) approximation. The motion of the dipole is unsteady but the potential vorticity contours move rigidly. The vortex comprises three potential vorticity anomaly modes, with a radial dependence given by the spherical Bessel functions and with azimuthal and polar dependences given by the spherical harmonics. The first mode, or spherical mode, accounts for the horizontal asymmetry of the vortex dipole and curvature of the dipole's horizontal trajectory. The second mode, or dipolar mode, accounts for the speed of displacement of the vortex dipole. A third mode, or vertical tilting mode, accounts for the dipole's vertical asymmetry. The QG vertical velocity field has two contributions: the first one is octupolar and depends entirely on the dipolar mode, and the second one is dipolar and depends on the nonlinear interaction between dipolar and vertical tilting modes, Partial support for this study was obtained through project CTM2014-56987-P (Spanish Ministry of Science and Innovation), Peer Reviewed

18 pages, 11 figures, 3 tables, Here we explore the water transfer between the subtropical and tropical gyres of the South Atlantic Ocean to better understand its unique equatorward heat delivery. A Lagrangian technique is applied to the reanalysis product GLORYS2V4 in order to trace back the western boundary flow in the tropical (North Brazil Undercurrent, NBUC) and subtropical (Brazil Current) gyres. Most of the northward NBUC core transport (14.9 Sv at 8°S) arrives from the eastern boundary subtropical current (Benguela Current) via the zonal South Equatorial Current. This subtropical-tropical transfer represents the core of the returning limb of the Atlantic meridional overturning circulation and accounts for most of the observed increase in heat and salt-volume transports (0.18 PW and 0.19 Sv from 30°S to 8°S, respectively) across the South Atlantic. The NBUC also includes Antarctic Intermediate Water below 400 m (7.4 Sv at 8°S) coming from the interior subtropical gyre, as well as water from the current's surface and peripheral components coming from the tropical gyre (13.3 Sv at 8°S). The Brazil Current (9.9 Sv at 29°S) is mostly composed of subtropical water originating in the upper 800 m west of the eastern boundary current at 30°S (8.5 Sv), with a minor contribution of surface tropical water that transfers to the subtropics (1.4 Sv), A. Cabré is grateful to the Beatriu de Pinos fellowship and the program Marie Curie Actions COFUND of the 7th Framework Program for Research and Technological Development of the European Union. I. Vallès‐Casanova acknowledges an FPI contract (BES‐2015‐071314) from the Spanish government. We also acknowledge funding from the Spanish government through projects VA‐DE‐RETRO (reference CTM2014‐56987‐P) and SAGA (reference RTI2018‐100844‐B‐C33), Peer Reviewed

24 pages, 7 figures, 10 tables, 2 appendices, supplementary material https://doi.org/10.1016/j.pocean.2019.102136, Mass transports for the thermocline, intermediate, deep and abyssal layers in the Atlantic Ocean, at 30°S and for 2003 and 2011, have been estimated using data from GO-SHIP hydrographic transoceanic sections and applying three inverse models with different constraints. The uppermost layers comprise South Atlantic Central Water (SACW) and Antarctic Intermediate Water (AAIW), with a net northward transport in the range of 12.1–14.7 Sv in 2003 and 11.7–17.7 Sv in 2011, which can be considered as the northward returning limb of the Meridional Overturning Circulation (MOC). The western boundary Brazil Current transports twice as much SACW in 2003 (−20.2 ± 0.7 Sv) than in 2011 (−9.7 ± 0.7 Sv). A poleward current consisting of AAIW and Upper Circumpolar Deep Water (UCDW) flows beneath the Brazil Current. The eastern boundary Benguela Current, characterized by a high mesoscale eddy activity, transports 15.6 ± 0.9 Sv in 2003 and 11.2 ± 0.8 Sv in 2011, east of the Walvis Ridge. In the ocean interior, the northward flow is mainly located east of the Mid Atlantic Ridge (MAR) where Agulhas Rings (ARs), observed in both 2003 and 2011, transport warm and salty water from the Indian to the Atlantic Ocean. For the deep layers, the southward transport of North Atlantic Deep Water (NADW) occurs as the Deep Western Boundary Current and also in the eastern basin. The western and eastern basins transport similar amounts of NADW to the south during both years, although the eastern pathway changes substantially between both years. The total NADW transport, which is also considered the MOC, is in the range 16.3–24.5 Sv in 2003 and 17.1–29.6 Sv in 2011, hence with no significant change, This study has been performed as part of projects: US CLIVAR Repeat Hydrography Program, which is now part of the International GO-SHIP project, with US funding from the US National Oceanic and Atmospheric Administration (NOAA) Climate Program Office, and National Science Foundation Geoscience Division, BOUNDARY (ProID2017010083) funded by RIS-3, PO Feder Canarias, VA-DE-RETRO (CTM2014-56987-P) and SAGA (RTI2018-100844-B-C31) funded by the Spanish Government. [...] EM was supported by NERC national capability funding through the ORCHESTRA (NE/N018095/1) and CLASS (NE/R015953/1) projects, Peer Reviewed

19 pages, 14 figures, 1 table, supporting information https://doi.org/10.1002/joc.6247, We combine daily in situ precipitation data with meteorological reanalysis data in order to explore the contribution of cut-off low systems to the seasonal and inter-annual rainfall variations over Baghdad from 2005 to 2016. During these 12 years (average rainfall of 131 ± 67 mm/year), 38 rainy cut-off lows brought 43% of the total precipitation, with extreme inter-annual variations. Indeed, precipitation associated with autumn cut-off lows was the principal factor that turned an arid into a wet year: during the three most arid years cut-off lows contributed about 25% of the average rainfall (10 out of 40 mm/year) while during the three wettest years they contributed near 67% (171 out of 254 mm/year). The extreme-rain cut-off low systems displayed analogous synoptic characteristics: upper-atmosphere divergence, upwards vertical motions in the middle atmosphere, and lower-atmosphere winds into central Iraq at times when the surface Red Sea and Persian Gulf waters were warmer than the surface air. During those days previous to an extreme event, the surface waters cooled substantially and the amount of precipitable water increased largely, suggesting high latent heat transfer. In order to characterize those conditions that favour rainfall, we focus on the November 18–20, 2013 cut-off low system, which led to the largest flooding and wettest year in Baghdad between 2005 and 2016. The distribution of properties in the middle (500 hPa) and upper (250 hPa) troposphere shows that the region was affected by intense horizontal divergence and upwards motions, coinciding with a surface low over the Arabian Peninsula that caused intense northwards winds over the Persian Gulf and brought substantial moisture to central Iraq. The analysis of several stability indexes indicates that convective instability played a secondary role during the episode., This work has been supported by projects VA‐DE‐RETRO (CTM2014‐56987‐P), FLUXES (CTM2015‐69392‐C3‐3‐R), TECBIOMET (CTM2017‐89565‐C2‐1‐P), and SAGA (RTI2018‐100844‐B‐C33), funded by the Spanish government. Ali Raheem Al‐Nassar wishes to thank the Iraqi Ministry of Higher Education and Scientific Research and the Mustansiriyah University for their support to carry out this research, With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

10 pages, 4 figures, supporting information https://doi.org/10.1029/2020GL087108.-- The HadISST1 data were provided by UK Met Office at https://www.metoffice.gov.uk/hadobs/hadisst. The NCEP‐NCAR reanalysis, the NOAA gauge observation‐based global land precipitation reconstruction data, the COBE data and the ERSST5 data were provided by NOAA/ESRL/PSD at http://www.esrl.noaa.gov/psd. The ORAS4 data were provided by the Copernicus Marine Environment Monitoring Service (CMEMS) at ftp://ftp‐icdc.cen.uni‐hamburg.de/EASYInit/ORA‐S4/monthly_1x1, The spatiotemporal evolutions of equatorial Atlantic sea surface temperature anomalies (SSTAs) during Atlantic Niño events and the associated climate impacts on the surrounding continents are extremely diverse. In this study, we construct longitude‐time maps of equatorial Atlantic SSTAs for each observed Atlantic Niño event during 1948–2019 and perform a spatiotemporal empirical orthogonal function analysis to identify the four most frequently recurring Atlantic Niño varieties. The first two contrast the timing of dissipation (early terminating vs. persistent) and the other two the timing of onset (early onset vs. 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. Most of the varieties are subject to onset mechanisms that involve preconditioning in boreal spring by either the Atlantic meridional mode or Pacific El Niño, while for the late onset variability 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), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

11 pages, 5 figures, 1 appendix, supplementary movies https://doi.org/10.1017/jfm.2019.730, An exact solution of a stable vortex tripole in two-dimensional (2-D) Euler flows is provided. The stable tripole is composed of an inner elliptical vortex and two small-amplitude lateral vortices. The non-vanishing vorticity field of this tripole, referred to as here as an embedded tripole because of the closeness of its vortices, is given in elliptical coordinates (,) by the even radial and angular order-0 Mathieu functions Je0 () ce0 () truncated at the external branch of the vorticity isoline passing through the two critical points closest to the vortex centre. This tripole mode has a rigid vorticity field which rotates with constant angular velocity equal to 0 Je0 (1) ce0 (0)/ 2, where 1 is the first zero of Jef0 () and 0 is a constant modal amplitude. It is argued that embedded 2-D tripoles may be conceptually regarded as the superposition of two asymmetric Chaplygin–Lamb dipoles, separated a distance equal to 2R, as long as their individual trajectory curvature radius R is much shorter than their dipole extent radius, Partial supportfor this study was obtained through project CTM2014-56987-P (Spanish Ministry of Science and Innovation)

11 pages, 7 figures, 3 tables, This dataset, gathered during the RETRO-BMC cruise, reports multiple-scale measurements at the Confluence of the Brazil and Malvinas Currents. The cruise was carried out between 8 and 28 April 2017 onboard R/V Hespérides, departing from Ushuaia and arriving to Santos. Along its track, the vessel recorded near-surface temperature and salinity, as well as the horizontal flow from 20 m down to about 800 m. A total of 33 hydrographic stations were completed in a region off the Patagonian Shelf, within 41.2°S–35.9°S and out to 53.0°W. At each station, a multiparametric probe and velocity sensors were deployed inside the frame of a rosette used to collect water samples at selected depths; these samples were later used for several water analyses, including inorganic nutrient concentrations. Microstructure measurements were carried out in 11 of these hydrographic stations. In addition, two high-resolution three-dimensional surveys were conducted with an instrumented undulating vehicle between 40.6°S–39.0°S and 55.6°W–53.8°W. Lastly, eight high-frequency vertical profilers were deployed in the region and five position-transmitting drifters were launched. These data allow the description of the Confluence from the regional scale to the microscale, and provide a view of the variability of the frontal region on time scales from days to weeks, This research has been supported by the Spanish government (Ministerio de Economía and Competitividad through project VA-DE-RETRO, CTM2014-56987-P, and Ministerio de Ciencia, Innovación y Universidades through project SAGA, RTI2018‐100844‐BC33). Dorleta Orúe-Echevarría (FPU2013-02884) and Ignasi Vallés-Casanova (BES‐2015‐071314) have also been funded with PhD scholarships by the Spanish government (Ministerio de Ciencia, Innovación y Universidades). Paola Castellanos has been partly supported by the Portuguese government (Fundação para a Ciência e a Tecnologia through project COASTNET, PINFRA/22128/2016), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

11 pages, 7 figures, 4 tables, supplementary material https://doi.org/10.1016/j.ijheatmasstransfer.2020.120185.-- This article is a publication of the Unidad Océano y Clima of the Universidad de Las Palmas de Gran Canaria, a R+D+I CSIC-associate unit, The large uncertainties in the forecasting of future global climatic conditions endorse the need of developing simple yet credible predicting tools. Here we propose a three-zone steady-state radiative model that maximizes latitudinal heat fluxes and considers the potential effect of the Earth's declination. The model is formulated as a set of five equations and six unknowns (zonal temperatures and widths, and the latitudinal heat transport) that requires specifying the reflected (albedo) and back-to-Earth (greenhouse) radiation fractions and obliges turning the low-latitude temperature into an additional parameter. The results do depend on the Earth declination, with changes of 0.5/1.5 K in the intermediate/high zones, which is interpreted as potentially affecting the greenhouse and high-latitude albedo coefficients. Therefore, we focus on identifying the effects of changes in these parameters – properly selected to represent last-glacial-maximum, modern and end-of the-century conditions. The main change is a large rise of the high-latitude temperature, favored both by a decrease in the high-latitude albedo and an increase in the greenhouse factor. For the other variables, the temporal changes in albedo and greenhouse gases compete among them, resulting in one trend from glacial to modern times and a reversal between preindustrial times and the end of the 21st century (currently a warming-narrowing of the intermediate region and the widening of both the low- and high-latitude zones); however, we note that an increase in the low-latitude temperature would tend to alleviate these changes. Despite its simplicity, the model leads to realistic global trends, becoming a useful simple tool for exploring the sensitivity of the Earth's heat distribution to changes in radiative fluxes and endorsing the validity of the maximum latitudinal-heat-transport premise, This work has been funded by the Spanish Government through projects VA-DE-RETRO (Ministerio de Economía y Competitividad, ref. no. CTM2014-56987-P) and SAGA (Ministerio de Ciencia, Innovación y Universidades, ref. no. RTI2018-100844-B-C33), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

8 pages, 5 figures, [EN] The oceans are origin and instrument for the life of a planet that, paradoxically, we call Earth. The oceans keep most of the water and other properties that flow in the cycle of life, all of them conditioned by the energy that comes from the Sun. This insolation reaches the surface waters according to latitude and time, and it is incorporated and distributed through the oceans as heat and mechanical and chemical energy. During the processes of incorporation and transformation, the thermodynamic and dynamic conditions of the regional habitats are defined, which give rise to biogeochemical properties and typical communities, and the ocean currents, with a broad range of temporal patterns and spatial structures, shape a circulatory system analogous to other living organisms. A complex network of subsystems with complementary tasks is established: the great planetary organism emerges!, [CAT] Els oceans són origen i instrument per a la vida del planeta que, paradoxalment, anomenem Terra. Els oceans guarden la major part de l’aigua i altres propietats que flueixen en el cicle de la vida, totes elles condicionades per l’energia que ens ve del Sol. Aquesta insolació arriba a les aigües superficials en funció de la latitud i el temps, i s’incorpora i distribueix pels oceans en forma de calor i energia mecànica i química. Durant els processos d’incorporació i transformació, es defineixen les condicions termodinàmiques i dinàmiques dels hàbitats regionals, que donen peu a característiques biogeoquímiques i comunitats pròpies, i són els corrents oceànics els que, amb tot un ventall de patrons temporals i d’estructures espacials, conformen un sistema circulatori anàleg al d’altres éssers vius. S’estableix una xarxa complexa de subsistemes amb tasques complementàries: sorgeix el gran organisme planetari!, Les idees aquí presentades han sorgit al llarg de més d’una dècada de feina en el marc de nombrosos projectes finançats pel Plan Nacional de I+D (CANOA, referència CTM2005-00444/MAR; MOC2, referència CTM2008-06438-CO2; TIC-MOC, referència CTM2011-28867; VA-DE-RETRO, referència CTM2014-56987-P; SAGA, referència RTI2018-100844-B-C33) i pel CSIC (FISIO-CEAN, referència PIF2008-30F0061), Peer reviewed

25 pages, 18 figures, 3 tables, 1 appendix, 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, We acknowledge support from the Spanish Government through grants CTM2011-28867 (TIC-MOC project), CTM2014-56987-P (VA-DE-RETRO project) and RTI2018-100844-B-C33 (SAGA project), and through the funding of PhD scholarships for D.O.E. (FPU2013-02884), C.H. (CSIC JAE-Predoc program), S.R.G. (BES-2012-055970) and I.V.C. (BES-2015-071314). We also recognize the institutional support of the Spanish Government through the Severo Ochoa Centre of Excellence accreditation (CEX2019-000928-S), Peer reviewed

12 pages, 8 figures, 1 table.-- Data availability: Data will be made available on request, Subpolar coastal waters are key hotspots in the global carbon cycle. However, the small-scale distribution of partial pressure of carbon dioxide (pCO2) in these environments and the physical and biological controls underlying this variability are still poorly understood. Here, we examine simultaneous high-resolution spatial measurements of wind speed and pCO2, temperature, salinity, and in-vivo chlorophyll-a fluorescence (chl-a fluo, a proxy of phytoplankton biomass) in surface waters that were obtained during an oceanographic survey in the Argentinian Beagle Channel (subantarctic Atlantic Patagonian) in early fall 2017. The 240 km study transect (centered at 55°S - 67°W) was divided into two zones: (A1) The Beagle Channel innermost portion, semi-enclosed and subject to strong continental influence and (A2) its eastern outlet towards the open Southwest Atlantic. Discrete seawater samples were also collected for apparent oxygen utilization (AOU), nutrients and pH measurements. High-resolution spatial measurements revealed the persistence of pCO2 below atmospheric equilibrium, increasing in median (interquartile range 25–75%) from 314 μatm in the inner Beagle Channel (A1) to 348 μatm towards the adjacent open sea (A2). A decrease in atmospheric CO2 sequestration was associated with an increase in water temperature from 9.5 °C to 10.7 °C, salinity from 30.8 to 32.5, and chl-a fluo from 2.24 to 2.91 mg m−3 along the coastal-offshore gradient. Low AOU and nutrient levels were found in regions inside the channel. Indeed, the relationships between CO2 and temperature or salinity were significantly different from those expected from the theoretical solubility effect, indicating a dominance of metabolic over physicochemical controls on this gas. Moreover, physical factors such as vertical stratification contributed to the variable surface pCO2 values. These findings reveal the existence of short-scale spatial variability of CO2 in the Beagle Channel, improving our understanding of the multiple controls on atmospheric carbon sequestration in extensive subpolar continental shelves, We acknowledge support from the Spanish Government through grants CTM2014-56987-P (VA-DE-RETRO Project) and RTI2018-100844-B-C33 (SAGA project) and also recognize the institutional support of the Spanish Government through the Severo Ochoa Centre of Excellence accreditation (CEX2019-000928-S). This study was funded by grants from the Council for Research and Scientific Development of Brazil (CNPq, 203366/2019-0, 314995/2020-0) and the Research Support Foundation of the State of Rio de Janeiro (E-26/211.329/2021 and E-26/201.118/2022). H.M. and L.C.C. were awarded by CNPq Research Productivity and FAPERJ Scientist of Our State fellowships. L.C.C. was awarded by UERJ/PROCIENCIA fellowship, Peer reviewed

13 pages, 5 figures, supporting information https://doi.org/10.1029/2022JC018730.-- Data Availability Statement: Microstructure data are available at https://microstructure.ucsd.edu/#/cruise/740H20111224. World Ocean Atlas 2018 climatological data are available from https://www.ncei.noaa.gov/archive/accession/NCEI-WOA18, The rates of isopycnal stirring and water mass transport by mesoscale eddies, and of diapycnal mixing by small-scale turbulence, across the Brazil-Malvinas Confluence (BMC) are assessed from a set of microstructure and hydrographic measurements in the Argentine Basin. This assessment is founded on a theoretical framework that applies a triple decomposition to the temperature variance equation and assumes eddies to transfer potential vorticity downgradient. The BMC is found to host widespread intense isopycnal stirring at rates of O(103–104 m2 s−1), and generally weak diapycnal mixing at rates of O(10−6–10−5 m2 s−1). Despite such disparity, both diapycnal mixing and isopycnal stirring play roles of comparable importance in determining regional water mass properties within surface and mode waters. In deeper layers, isopycnal stirring prevails. Eddies are further diagnosed to effect an important cross-BMC transport, at rates of O(1 m2 s−1). When scaled by the along-stream extent of the BMC, these rates integrate to volume transports that may be as large as O(10 Sverdrups). This suggests that cross-BMC transfers of waters are substantially effected by eddy-induced flows, We acknowledge support from NSF Grant #OCE-1208454 for collection and analysis of the data and the Spanish Government through grants CTM2014-56987-P (VA-DE-RETRO Project) and RTI2018-100844-B-C33 (SAGA project) and through the funding of PhD scholarship for D.O.E. (FPU2013-02884). We also recognize the institutional support of the Spanish Government through the Severo Ochoa Centre of Excellence accreditation (CEX2019-000928-S), Peer reviewed