This study explores three decades (1993-2022) of interannual variability in primary production (PP) using a coupled physical-biogeochemical model. A long-term positive trend in the vertically-integrated PP was found in both the central and northern domains, exceeding 6 mol C m-2 yr-1 per decade, highlighting an increasing contribution of these regions to overall productivity. Over the study period, the region produced a cumulative 8.6 billion metric tons of carbon, underscoring its substantial role as a carbon sink despite its relatively small spatial extent. Interannual climatic events strongly modulated PP. Negative PP anomalies during El Ni & ntilde;o events and positive PP anomalies during La Ni & ntilde;a phases were primarily constrained within the first 10 m depths. The sensitivity analysis demonstrated that biological drivers, particularly chlorophyll concentration and phytoplankton biomass, dominated PP variability, accounting for over 95% of the explained variance. Physical factors, such as light availability, temperature, played secondary but significant roles during extreme events, modulating PP alongside biological processes. Overall, the findings reveal a resilient yet highly dynamic system, with long-term increases in productivity counterbalanced by episodic disruptions tied to interannual climatic variability. These results emphasize the importance of biological drivers in sustaining productivity and provide valuable insights into the factors shaping the variability and trends in this highly productive marine ecosystem.

The Gulf of Arauco, a highly productive area, sustains some of the primary epipelagic, mesopelagic, and benthic resources in the Southern Humboldt Current System. It is also an important nursery and spawning area. High productivity is driven by seasonal and synoptic wind variability, coastal upwelling, topographic upwelling from the Biobio Submarine Canyon, and freshwater flow, mostly from the Biobio River. The effect of freshwater discharge on early-stage fisheries resources has been poorly studied in central Chile, making our research all the more significant. From 2014 to 2018, a high-resolution interannual biophysical simulation incorporating the Biobio River freshwater discharge was conducted. It allowed us to thoroughly examine the impact of the Biobio River on the abundance and transport of anchovy early-life stages in the Gulf of Arauco. To ensure the accuracy of our findings, we compared model results to in-situ biological/hydrographic data in the Gulf of Arauco from 2007 to 2019. The biophysical model was run with release pulses every five days from September 1 to October 31. In the research area, the months of September and October have traditionally been identified as anchovy spawning months. The simulation was evaluated using General Linear Models, which suggested that larval survival would be influenced by the spawning's temporal fluctuation (year and day of release). The extension of the Biobo River plume, identified using the potential energy anomaly, was found to be similar to the observations. The model results showed that larvae were largely transported northward, and spawning zones from the research period showed strong retention in the Gulf of Arauco. The highest abundances of anchovy early-life stages were found south of the Biobio River mouth, in highly stratified waters associated with the Biobio River plume in the Gulf of Arauco. Significant correlations between Biobio River's monthly mean discharge, river plume extension, and anchovy early-life stages abundance were observed from 2014 to 2018, both for simulated and in situ data. However, when considering a larger egg in situ abundance time series data in situ (from 2007 to 2019), significant correlations were observed between egg abundance and the river plume extension area (R2 = 0.7 p = 0.03) only up to a threshold value, which ranged from 338 to 357 km2); below and above this threshold, abundance dropped drastically. This research concludes that the Biobio River is an essential factor regulating the early stages of the life of anchovy in the Gulf of Arauco.

The Casamance estuary, located in southern Senegal, is a region of remarkable ecological, tourist and economic significance. It undergoes strong seasonal variations of salinity due to its reverse estuary nature during the dry season. This study aims to characterize tidal dynamics in the western part of the Casamance estuary, spanning from the river mouth to the town of Ziguinchor, during the dry season. Utilizing a three-dimensional, non-linear model with a high spatial resolution, we focused on simulating the tidal elevations and currents and evaluating them with sea level and current measurements both within the estuary and at its mouth. Whereas modelled tidal elevations agreed with observations, revealing eastward tidal propagation within the estuary, tidal currents near the river mouth and into the estuary were underestimated. The Eulerian residual circulation was mainly seaward whereas the Lagrangian residual circulation was significantly weaker due to compensation by the Stokes drift. This modeling study marks a crucial first step towards conducting comprehensive environmental impact assessments in the Casamance estuary, paving the way for a deeper understanding and preservation of this region.

The oxygen minimum zone (OMZ) in the Gulf of California entrance (GCE) is a crucial feature of the northeastern tropical Pacific, significantly influencing regional biogeochemical cycles and marine ecosystems. This study investigates the seasonal and interannual variability of the OMZ upper boundaries using a high-resolution physical-biogeochemical coupled model. The model results are evaluated against satellite observations, Argo profiles, and in situ data, demonstrating its capability to capture key dynamical processes, including mesoscale eddies, poleward undercurrents, and coastal-trapped waves (CTWs). The high-resolution CROCO-PISCES model reveals two alternating periods of shoaling and deepening of the OMZ upper boundary in the Gulf of California Entrance, modulated by seasonal mesoscale dynamics and coastal-trapped wave (CTW) propagation. This study provides novel insights into the interannual influence of El Nino Southern Oscillation (ENSO) events on OMZ dynamics, with El Nino driving significant deepening and contraction of the OMZ, and La Nina promoting shoaling and expansion. These variations are linked to changes in mesoscale dynamics, particularly the modulation of anticyclonic circulation at the Gulf's entrance by equatorially forced CTWs associated with ENSO. The study highlights the complex interplay between local and remote oceanographic processes in determining the OMZ variability in the GCE. This research provides insights into the mechanisms driving OMZ dynamics in the Gulf of California and underscores the need for integrated observational and modeling approaches to predict the response of OMZs to ongoing climate variability.

​​​​​In tropical regions, the fresh water flux entering into the ocean originates primarily from precipitations and, in a lesser extent, from continental rivers. Nevertheless, at regional scale, river flows can have a significant impact on the surface ocean dynamics. Riverine fresh water modifies salinity, and therefore density, stratification and circulation in the surface layer. The eastern Southern North Tropical Atlantic (e-SNTA) region off Northwest Africa, with its particular coastline, relatively high cumulative river discharge and the vicinity of ITCZ, is a particularly interesting location to study the linkage between precipitations, river flows and Sea Surface Salinity (SSS). In particular, the effect of river flows interannual anomalies on SSS have been unexplored in this region.In this work, we focus on the regional SSS interannual variability, and their relations to river discharge and rainfall. We quantify the impact of these forcings on surface salinity and dynamics, combining informations coming from the CROCO regional ocean model and from SSS remote sensing. Several simulations forced by different interannual and climatological forcings are analyzed. We compare the simulated SSS with satellite (ESA CCI product), in-situ (Argo, ships and Melax mooring datasets), and Glorys reanalysis. The mixed layer salinity budget is investigated to better understand the dynamics driving SSS variability.Overall, the simulations are in good agreement with the observations, with a slight statistical improvement in the river plume regions when using ISBA interannual runoff and IMERG precipitation. We find that interannual SSS variability depends on surface circulation, river discharge, precipitation and wind variability. Strong anomalies are mostly linked to strong precipitation anomalies. The impact of river discharge is highly dependent on surface currents. This highlights the importance of properly constraining river runoff and precipitation to simulate realistic sea surface salinities. This study shows the value of satellite salinity data for validating ocean models, and highlights the potential contribution of future L-band radiometric missions for coastal ocean observation.

The Chilean Inland Sea (CIS) and the fjords region in Southern Chile host human activities such as salmon aquaculture. During the productive austral summer, the CIS exchanges heat, salt, dissolved oxygen, and nutrients with the Southern Pacific Ocean via the Guafo Mouth, a very shallow strait. Tides influence the productivity of the CIS, a high-frequency forcing typically not considered in circulation models when estimating exchange fluxes. In this work, the inflow, outflow, net, mass, and nutrient fluxes through the Guafo Mouth are evaluated using a high-resolution regional model forced by tides. Model output (temperature, salinity, and currents) is compared to hydrodynamic data. The impact of tidal forcing on summer-mean currents and transports is quantified. These findings are compared with results from a lower-resolution, commonly used, general circulation model. A Lagrangian modeling approach highlights that the water masses transiting from the open ocean through the Guafo Mouth mainly originate from the region south of the mouth.

Abstract The Canary current upwelling System (CCS) is one the most productive marine ecosystems. CMIP5 simulations under the RCP8.5 scenario for the end of the 21st century project a modest upwelling‐favorable wind decrease over the CCS southern outpost, that is, the southern senegalese upwelling center (SSUC). We explore the coastal‐scale physical manifestations of climate change in the SSUC through dynamical downscaling of projected changes from nine CMIP5 models selected for their realistic representation of present‐day thermohaline structure. We find that coastal upwelling reduction due to wind changes is projected to be aggravated by geostrophic/pressure adjustments related, in large part, to changes in upper ocean stratification. The reduction could reach 25% of present‐day upwelling rates. The intensity of the poleward boundary current offshore of the SSUC is projected to decrease. Together with upper ocean warming this opens vast possibilities of ecological evolutions with large impact on neighboring societies.

Coastal jets, characterized by wind maxima at low atmospheric levels, are a prominent feature of Eastern Boundary Upwelling Systems (EBUS) and play a crucial role in regional ocean dynamics and climate. These jets significantly affect environmental processes and human activities, particularly in marine ecosystems and fisheries. Despite their importance, the coastal jet in the Peruvian Upwelling System remains one of the least studied phenomena within EBUS.This study employs high-resolution (7 km) regional climate simulations using the Weather Research and Forecasting (WRF) model to analyze the characteristics of coastal jets off the coast of Peru. We performed a retrospective simulation for the period 1994–2003, driven by NCEP2 reanalysis data, to characterize the baseline conditions of coastal jets in terms of their frequency of occurrence, intensity, vertical structure, and directional patterns. The identification of coastal jets was based on a detailed analysis of vertical wind and temperature profiles, focusing on wind speed maxima at low atmospheric levels and their association with upwelling events and coastal features. The vertical profiles of wind and temperature were examined at multiple altitudes (from 10 m to 1000 m a.s.l.) to determine the spatial distribution, intensity, and vertical extent of these jets.In addition to the retrospective analysis, we conducted future climate projections for the period 2086–2095 under the RCP8.5 climate change scenario. The future simulations were forced with climate change signals derived from the CMIP5 ensemble, which includes the differences between monthly mean climatologies for the periods 2080–2100 and 1989–2009. These climate change forcings were added to the NCEP2 reanalysis data to simulate future atmospheric conditions. The future projections focus on the potential changes in the frequency, intensity, and altitude of coastal jets, as well as shifts in their seasonal patterns and directional tendencies.Results indicate that coastal jets occur year-round, with variations in frequency and spatial distribution. In summer, jets are more frequent and concentrated near the coastline, with intensities between 8 and 10 m.s⁻¹ and altitudes ranging from 200 to 300 m a.s.l. In contrast, winter coastal jets are less frequent but cover larger areas, with intensities between 9 and 11 m.s⁻¹ and altitudes of 400–500 m a.s.l. The predominant direction of the jets is south-southeast, parallel to the coastline, throughout the year, except in winter when significant occurrences are also observed from the southeast.Under the climate change scenario, the frequency of coastal jets is projected to increase, particularly along the northern and central coasts of Peru. A notable increase of up to 20% in frequency is expected during June, July, August, September, and October, especially north of the Paracas Peninsula (14°S). While the intensity of the jets remains largely unchanged, the vertical distribution of coastal jets is expected to shift, with a tendency towards lower altitudes in future projections.

Consequences of the mesoscale Thermal FeedBack (TFB) on the ocean dynamics are studied in the South-East Pacific (SEP) using a high-resolution regional ocean-atmosphere coupled model. Three simulations are compared: the first one is a fully coupled simulation. In the second one, the TFB has been removed with an online smoothing of the Sea Surface Temperature (SST) conditions used by the atmosphere. In the third one, to disentangle the impact of the nearshore and the offshore TFB, the smoothing is only applied in the offshore region. In the SEP, the coastal upwelling cold tongue constitutes a permanent mesoscale SST pattern. We show that this SST pattern alters the coastal wind structure, reducing the coastal upwelling-favorable wind intensity. So, the nearshore TFB reduces the coastal surface current and the vertical velocities. As a result, the Eddy Kinetic Energy (EKE) generation by baroclinic conversion is also weakened. In the offshore region, on the contrary, the oceanic mean state is not affected by the TFB and only the EKE is weakened. Composites above the coherent eddies show that the heat flux response to the mesoscale SST anomalies is responsible for the mesoscale activity weakening over the whole studied area. Although the wind response to the SST anomalies has a very weak mean impact on the EKE generation through wind work, we show that it strongly modifies the mean oceanic vertical velocity anomalies over the coherent eddies. The ocean dynamics is usually seen as driven by the atmosphere. However, the influence between the ocean and the atmosphere is mutual and the oceanic surface conditions feedback on the atmosphere. In this paper, we focus on the response of the atmosphere to the sea surface temperature mesoscale structures (structures that ranges from a few tens of km to a few hundred km). This response, called Thermal Feedback (TFB), is modeled with a high-resolution ocean-atmosphere coupled model to investigate its consequences on the oceanic dynamics in the South-East Pacific. This region is characterized by a wind-driven upwelling of sub-surface waters near the coast, forming a sea surface coastal cold tongue. We show that this structure alters in return the coastal wind structure, which contributes to reduce the upwelling and the surface current. The generation of mesoscale structures, such as coherent eddies and filaments, is also reduced. The mesoscale structures are also weakened in the offshore region. We analyze the atmospheric response above the coherent eddies and show that the heat flux response to the SST anomalies is responsible for the eddy damping. Vertical velocities are also created in the eddy by the wind response to the SST anomalies. Mesoscale thermal feedback decreases the mean coastal upwelling-favorable wind, surface current and nearshore eddy generation Mesoscale thermal feedback on the heat fluxes decreases the coherent eddy intensity through baroclinic conversion Coherent eddy mean vertical velocity is strongly modified by the mesoscale thermal feedback

A coupled physical-biogeochemical model was employed to explore the spatiotemporal dynamics of primary production (PP) rates within the Northern Humboldt Current System (NHCS). The coastal zone spanning 250 km from the shore, from 3°to 18°S, stands out as a highly productive upwelling region, exhibiting an average surface PP value of 2.5 mol C m−3 yr−1. Correspondingly, the average vertically integrated PP within the euphotic layer amounts to 13 mol C m−2 yr−1. In this context, summer emerges as the peak of productivity, yielding 18 mol C m−2 yr−1, while winter signifies the period of least productivity, with 9 mol C m−2 yr−1. Our study revealed that surface PP variability is primarily driven by changes in surface chlorophyll and phytoplanktonic biomass (mainly diatoms), followed by changes in photosynthetically active radiation (PAR) levels. During summertime, these three drivers contribute to substantial positive anomalies in surface PP. However, the reduction in nutrient availability resulting from weakened upwelling-favorable winds has a slight negative impact on surface PP rates. Yet, this decline is offset by a positive thermal effect during the warmer season. In contrast, during the winter season, a significant decrease in surface chlorophyll concentrations due to a vertical redistribution into a deeper mixed layer significantly diminishes surface PP. Furthermore, the reduction in both PAR levels and biomass concentrations has a comparable effect, further contributing to the decrease in surface PP rates during wintertime. At a depth of 20 m, changes in PP are primarily driven by variations between the opposing influences of PAR and chlorophyll concentrations. While PAR adheres to the seasonal cycle of warming and cooling throughout the year, chlorophyll-driven anomalies exhibit an inverse pattern to those at the surface, influenced by the vertical dilution effect within the mixed layer. Overall, this study provides valuable insights into the complex interplay of drivers that govern PP dynamics across various depths within one of the world’s most productive marine regions.

In tropical regions, the freshwater flux entering the ocean originates primarily from precipitation and, to a lesser extent when considering basin-scale averages, from continental rivers. Nevertheless, at the regional scale, river flows can have a significant impact on the surface ocean dynamics. Riverine freshwater modifies salinity and, therefore, density, stratification, and circulation. With its particular coastline and high cumulative river discharge, as well as its being in the vicinity of the intertropical convergence zone (ITCZ), the eastern part of the North Tropical Atlantic (e-NTA) region off northwestern Africa is a particularly interesting location to study the linkage between precipitation, river outflow, and sea surface salinity (SSS). Here, we focus on the regional e-NTA SSS seasonal cycle and interannual variability and on the impact of using various river runoff and precipitation forcing data sets to simulate SSS with a regional model. The simulated SSS values are compared with the Climate Change Initiative (CCI) satellite SSS values; in situ SSS values from Argo floats, ships, and a coastal mooring; and the GLORYS reanalysis SSS values. An analysis of the mixed-layer salinity budget is then conducted. Overall, the simulations reproduce the seasonal cycle and interannual variability well despite a positive mean model bias north of 15 degrees N. The seasonal cycle is impacted by the phasing of the different runoff products. The mixed-layer SSS decrease during the rainy season is mainly driven by precipitation followed by runoff by means of horizontal advection and is partly compensated for by vertical mixing. In terms of interannual anomalies, river runoff has a more direct impact on SSS than precipitation. This study highlights the importance of properly constraining river runoff and precipitation to simulate realistic SSS values and the importance of observing SSS in coastal regions to validate such constraints.

Synoptic intensification or relaxation of upwelling favorable winds are major sources of variability in eastern boundary upwelling systems. This study aims to investigate their impact on the planktonic ecosystem of the South Senegalese Upwelling Sector (SSUS), located south of the Cape Verde peninsula over a wide and shallow continental shelf. Numerical experiments using a three-dimensional coupled physical-biogeochemical model with four plankton functional types simulated the response of the coastal planktonic ecosystem to idealized synoptic (similar to 10 days) wind intensification and relaxation of the same amplitude. We find that these perturbations induce spatio-temporal oscillations of plankton concentrations. Zooplankton response occurred with a time lag that manifests itself in space as an equatorward/downstream shift in distribution relative to phytoplankton. Overall, the transmission of the synoptic perturbation from the physics to zooplankton is characterized by a damping in relative anomalies. All these elements and the weakness of the asymmetries in the biogeochemical/planktonic ecosystem responses between intensification and relaxation events support the hypothesis that synoptic variability has limited impact on the climatological state of low-latitude upwelling systems such as the SSUS.

The circulation and stratification in the shallow semi-enclosed bay of Paracas located downstream of the main upwelling cell off the Peruvian coast were studied during the summer season using a regional circulation model and in situ observations. A downscaling strategy based on a series of three embedded grids, from 10 km to 500 m resolution in the bay allows to take into account the influence of remote perturbations on the bay dynamics. Debiased surface winds from a high-resolution regional atmospheric model were used to force the model. The shortwave absorption depth was parameterized using satellite measurements of surface chlorophyll.Sensitivity experiments to the model forcing and parameterizations were performed to investigate the impact of the wind diurnal variability, tidal forcing, freshwater discharge from a nearby river and shortwave absorption depth on the bay stratification. Results show that: debiasing the wind intensity reduced the model cold bias in the bay and increase the stratification; a shallow shortwave absorption depth induced a cooling of the subsurface water, increasing the stratification; freshwater discharge from the Pisco river north of the bay increased slightly the stratification in the bay during days of weak wind. The high sensitivity of the bay stratification to the at-mospheric forcing calls for the need to use more realistic wind forcing products. The circulation in the bay under strong (>5.5 m s-1) and weak (<3 m s-1) winds was also examined. The summer circulation during strong upwelling-favorable wind conditions was characterized by northward surface currents transporting the bay surface waters outward and subsurface currents transporting cold deeper waters into the bay along its western shore. During weak wind conditions, the current is outward in the bottom layer and a surface southward current related to the poleward undercurrent flowing over the continental slope and shelf transported warm waters into the bay, generating a cyclonic circulation in the bay.

Off the central-southern Chilean coast (35°–38°S), the Gulf of Arauco is one of Chile's largest semi-enclosed coastal areas. It hosts industrialized activities within a highly productive zone of the Southern Humboldt Current System. One of the principal hydrodynamical forcings of the region is the Biobio River, whose discharge significantly influences coastal dynamics in the Gulf. The present work aims to study the impact of the Biobio River freshwater discharge on the circulation patterns in the Gulf of Arauco, using a high-resolution interannual simulation of the period 2013–2018. The simulation includes monthly interannual discharge from the significant four rivers for the study zone (Mataquito, Maule, Biobío, and Itata). The focus is primarily on wintertime (June–September), the highest freshwater discharges period. The modeled temperature and salinity fields were consistent with in-situ observations, presenting a moderate bias. The water masses highlighted in the TS diagrams, the temperature time series, and especially the currents near the Biobio River mouth were well represented in the simulation. It was found that the Biobio River strongly impacted the circulation in the Gulf of Arauco, intensifying the currents and causing a notable salinity decrease. Offshore zonal currents were intensified west of the Biobio River mouth, whereas southward alongshore currents were enhanced, especially during August. The influence of the Biobio River in the Gulf of Arauco was closely related to discharge strength. A strong relation between predominant southward downwelling-favorable wind stress and meridional currents was found, probably due to the formation of a buoyant coastal current strengthened by the wind-driven current during winter. Finally, surface buoyant waters associated with the river discharge generated a strong baroclinic zonal pressure gradient equilibrating the sheared meridional flow and enhancing the meridional ageostrophic pressure gradient, Reynolds stress, and near-surface vertical mixing of momentum.

In addition to their well-known seasonal cycle, eastern boundary upwelling systems (EBUS) undergo mod-ulation on shorter synoptic to intraseasonal time scales. Energetic intensifications and relaxations of upwelling-favorable winds with 5-10-day typical time scales can impact the EBUS dynamics and biogeochemical functioning. In this work the dynamical effects of wind-forced synoptic fluctuations on the South Senegalese Upwelling Sector (SSUS) are characterized. The region geomorphology is unique with its wide continental shelf and a major coastline discontinuity at its northern edge. The ocean response to synoptic events is explored using a modeling framework that involves applying idealized syn-optic wind intensification or relaxation to a five-member climatological SSUS ensemble run. Model evaluation against sparse midshelf in situ observations indicates qualitative agreement in terms of synoptic variability of temperature, stratifi-cation, and ocean currents, despite a moderate but systematic bias in current intensity. Modeled synoptic wind and heat flux fluctuations produce clear modulations of all dynamical variables with robust SSUS-scale and mesoscale spatial pat-terns. A mixed layer heat budget analysis is performed over the continental shelf to uncover the dominant processes in-volved in SSUS synoptic variability. Modulations of horizontal advection and atmospheric forcing are the leading-order drivers of heat changes during either wind intensification or relaxation while vertical dynamics is of primary importance only in a very localized area. Also, modest asymmetries in the oceanic responses to upwelling intensification and relaxation are only identified for meridional velocities. This brings partial support to the hypothesis that synoptic variability has a modest net effect on the climatological state and functioning of upwelling systems dynamics.

In addition to the wind seasonal cycle, Eastern Boundary Upwelling Systems undergo intraseasonal fluctuations. These synoptic fluctuations are characterized by an intensification or a relaxation of upwelling favorable winds of a period of about 10 days and are believed to have a major impact on the upwelling dynamics. Here we focus on the South Senegalese Upwelling System (SSUS) which is located south of the sharp Cape Verde peninsula which acts as an abrupt coastline break and has a particularly shallow continental shelf. Previous studies described not only the SSUS climatological dynamics but also the importance of synoptic events that play a major role in the observed variability. However, their precise impacts on the 3D dynamics on the shelf remain unclear and consequences on biogeochemistry are unknown. We identify the key dynamical and biogeochemical processes of the coastal ocean in its response to synoptic events. This is done using a modeling experiment that consists in applying idealized synoptic wind intensification and relaxation to climatological SSUS states (with CROCO-PISCES). We find that synoptic fluctuations affect the regional circulation and shape robust anomalies of temperature, boundary layer depth, sea surface height, surface and subsurface currents. Nutrients supply in the euphotic layer is significantly affected by synoptic fluctuations (+-30%). We find asymmetrical responses in nitrate, iron and silicate concentrations both between intensification and relaxation and between the inner and outer shelf regions. Persistent nitrate depletion is observed over the inner shelf. Phytoplanktonic ecosystem response to synoptic wind intensification thus differs spatially, with enhanced development of diatoms over the outer shelf and of nanophytoplankton over the inner shelf. Consequences on the zooplanktonic ecosystem are observed with a time delay and space shift, consistent with typical prey - predator relationships. Processes at play in the nutrients supply and planktonic ecosystem structure in response to synoptic fluctuations are discussed.

Máximos de viento en niveles bajos de la atmósfera ocurren frecuentemente sobre el mar peruano frente a la costa, denominados chorros o jets costeros. Estos jets costeros tienen un papel importante en la dinámica oceánica e impactos significativos en el clima y la ecología regional, así como en una serie de actividades humanas, por lo que las investigaciones sobre ellos son de mucha importancia. Este estudio presenta las características (frecuencia de ocurrencia, altura, intensidad y dirección) de los jets costeros frente a la costa peruana, usando datos de simulación atmosférica a alta resolución (7 km) con el modelo regional WRF, para el periodo 1994-2003, siguiendo un conjunto de criterios basado en el análisis de perfiles verticales del viento y de temperatura. Los resultados del análisis muestran que los jets costeros sobre el mar peruano pueden ocurrir durante todos los meses del año, sin embargo, varían en frecuencia y localización espacial. Estos jets son más frecuentes en verano y se concentran muy cerca de la costa. Predominantemente, tienen intensidad entre 8 y 10 m.s-1 y se presentan entre 200 y 300 m.s.n.m. Por otro lado, en invierno los jets costeros son menos frecuentes y tienen mayor extensión espacial; mayormente tienen intensidad entre 9 y 11 m.s⁻¹ y altura entre 400 y 500 m.s.n.m. Además, la dirección de los jets costeros es predominantemente sursureste (paralelo a la línea de costa) para todas las estaciones de año, excepto en invierno cuando el jet presenta también altas ocurrencias desde la dirección sureste.

Climate change is expected to result in smaller fish size, but the influence of fishing has made it difficult to substantiate the theorized link between size and ocean warming and deoxygenation. We reconstructed the fish community and oceanographic conditions of the most recent global warm period (last interglacial; 130 to 116 thousand years before present) by using sediments from the northern Humboldt Current system off the coast of Peru, a hotspot of small pelagic fish productivity. In contrast to the present-day anchovy-dominated state, the last interglacial was characterized by considerably smaller (mesopelagic and goby-like) fishes and very low anchovy abundance. These small fish species are more difficult to harvest and are less palatable than anchovies, indicating that our rapidly warming world poses a threat to the global fish supply.