Variability of the Southeast Pacific Subtropical Anticyclone and its impact on sea surface temperature off north-central Chile

Ancapichún, Santiago; Garces-Vargas, José

doi:10.7773/cm.v41i1.2338

Cited by 67 publications

(79 citation statements)

References 37 publications

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“…Our results agree with Ancapichún and Garcés-Vargas (2015), who demonstrated intensifi cation of the Southeast Pacifi c anticyclone from 2000 onward, which was accompanied by an increase in Ekman pumping along the northern and central coast of Chile. Additionally, the trend of change from 2000 onward matches the beginning of a decade of deceleration in sea surface warming on the global scale, most likely due to an increase of the SP trade winds (England et al 2014).…”

Section: Discussionsupporting

confidence: 93%

Contribution of Ekman pumping to the changes in properties and volume of the Eastern South Pacific Intermediate Water

Hernández-Vaca¹,

Schneider²,

Garces-Vargas³

2017

Gayana (Concepc.)

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Contribución del bombeo de Ekman a los cambios en las propiedades y volumen del RESUMENUna actualización de la distribución del Agua Intermedia del Pacífi co Sur Oriental (AIPSO) fue realizada con datos ARGO (Array for Real-Time Geostrophic Oceanography). Este estudio comprendió más de 46.000 perfi les obtenidos durante 2007-2012 del área entre la costa occidental de Sudamérica y 150° O, y 5°S y 40°S. Esta información se complementó con datos de las secciones P06 del World Ocean Circulation Experiment (WOCE) realizadas en 1992 y 2010 en 32° 30'S en el Océano Pacífi co Sur. Comparando ésta actualización y los datos de 1990-2001 se estableció que el volumen del AIPSO ha aumentado aproximadamente un 53%. Además, el área ocupada por AIPSO en el transecto WOCE P06 de 2010 fue 48% más grande que en 1992. La velocidad de bombeo Ekman, calculada a partir del viento para el tiempo y la región de la formación del AIPSO, mostró un aumento signifi cativo en el bombeo de Ekman entre 2000 y 2012. El aumento del bombeo de Ekman desde el 2000 podría explicar los cambios observados en la distribución del AIPSO (la masa de agua se extendió zonalmente) y las propiedades (la salinidad disminuyó 0.1). Estos cambios podrían explicarse como la consecuencia de la variabilidad climática atmosférica sobre el océano interior.Palabras clave: Pacífi co Sur, rotor del esfuerzo del viento, agua intermedia, subducción.Gayana 81(2): 52-63, 2017.

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Section: Discussionsupporting

confidence: 93%

Contribution of Ekman pumping to the changes in properties and volume of the Eastern South Pacific Intermediate Water

Hernández-Vaca¹,

Schneider²,

Garces-Vargas³

2017

Gayana (Concepc.)

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“…A possible mechanism driving the local variability observed at the southern section is the generation of local baroclinic instability and vorticity input from wind stress curl as observed for the Califor- nia system (Kelly et al, 1998). The southern section lies within the northeastern rim of the southeast Pacific anticyclone, and the peak in the seasonal DO eddy flux coincides with the reported intensity peak of the seasonal cycle of the Anticyclone, towards the end of the year (Rahn et al, 2015;Ancapichún and Garcés-Vargas, 2015). Therefore, the mesoscale activity in this region could be directly modulated by the winds.…”

Section: Discussionmentioning

confidence: 99%

Seasonal variability of the oxygen minimum zone off Peru in a high-resolution regional coupled model

et al. 2016

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Abstract. In addition to being one of the most productive upwelling systems, the oceanic region off Peru is embedded in one of the most extensive oxygen minimum zones (OMZs) of the world ocean. The dynamics of the OMZ off Peru remain uncertain, partly due to the scarcity of data and to the ubiquitous role of mesoscale activity on the circulation and biogeochemistry. Here we use a high-resolution coupled physical/biogeochemical model simulation to investigate the seasonal variability of the OMZ off Peru. The focus is on characterizing the seasonal cycle in dissolved O 2 (DO) eddy flux at the OMZ boundaries, including the coastal domain, viewed here as the eastern boundary of the OMZ, considering that the mean DO eddy flux in these zones has a significant contribution to the total DO flux. The results indicate that the seasonal variations of the OMZ can be interpreted as resulting from the seasonal modulation of the mesoscale activity. Along the coast, despite the increased seasonal low DO water upwelling, the DO peaks homogeneously over the water column and within the Peru Undercurrent (PUC) in austral winter, which results from mixing associated with the increase in both the intraseasonal wind variability and baroclinic instability of the PUC. The coastal ocean acts therefore as a source of DO in austral winter for the OMZ core, through eddy-induced offshore transport that is also shown to peak in austral winter. In the open ocean, the OMZ can be divided vertically into two zones: an upper zone above 400 m, where the mean DO eddy flux is larger on average than the mean seasonal DO flux and varies seasonally, and a lower part, where the mean seasonal DO flux exhibits verticalzonal propagating features that share similar characteristics than those of the energy flux associated with the annual extratropical Rossby waves. At the OMZ meridional boundaries where the mean DO eddy flux is large, the DO eddy flux has also a marked seasonal cycle that peaks in austral winter (spring) at the northern (southern) boundary. In the model, the amplitude of the seasonal cycle is 70 % larger at the southern boundary than at the northern boundary. Our results suggest the existence of distinct seasonal regimes for the ventilation of the OMZ by eddies at its boundaries. Implications for understanding the OMZ variability at longer timescales are discussed.

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“…On the other hand, Cheuque, Chaihuín, and Pucatrihue are management and exploitation areas for benthic resources where the exploitation of intertidal macroalgae and invertebrates by small-scale artisanal fishermen is regulated (Gelcich et al, 2010). During the last decades, the intensification and southward migration of the Southeast Pacific Subtropical Anticyclone have led to a strong cooling of coastal sea surface temperatures in the region of the southeastern Pacific located to the south of 33°S (Ancapichún & Garcés-Vargas, 2015). Satellite-derived MODIS data were downloaded from http://oceancolor.gsfc.nasa.gov/.…”

Section: Studyregionandenvironmentalconditionsmentioning

confidence: 99%

Context‐dependent functional dispersion across similar ranges of trait space covered by intertidal rocky shore communities

Valdivia

Segovia-Rivera

Fica

et al. 2017

Ecology and Evolution

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Functional diversity is intimately linked with community assembly processes, but its large‐scale patterns of variation are often not well understood. Here, we investigated the spatiotemporal changes in multiple trait dimensions (“trait space”) along vertical intertidal environmental stress gradients and across a landscape scale. We predicted that the range of the trait space covered by local assemblages (i.e., functional richness) and the dispersion in trait abundances (i.e., functional dispersion) should increase from high‐ to low‐intertidal elevations, due to the decreasing influence of environmental filtering. The abundance of macrobenthic algae and invertebrates was estimated at four rocky shores spanning ca. 200 km of the coast over a 36‐month period. Functional richness and dispersion were contrasted against matrix‐swap models to remove any confounding effect of species richness on functional diversity. Random‐slope models showed that functional richness and dispersion significantly increased from high‐ to low‐intertidal heights, demonstrating that under harsh environmental conditions, the assemblages comprised similar abundances of functionally similar species (i.e., trait convergence), while that under milder conditions, the assemblages encompassed differing abundances of functionally dissimilar species (i.e., trait divergence). According to the Akaike information criteria, the relationship between local environmental stress and functional richness was persistent across sites and sampling times, while functional dispersion varied significantly. Environmental filtering therefore has persistent effects on the range of trait space covered by these assemblages, but context‐dependent effects on the abundances of trait combinations within such range. Our results further suggest that natural and/or anthropogenic factors might have significant effects on the relative abundance of functional traits, despite that no trait addition or extinction is detected.

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Variability of the Southeast Pacific Subtropical Anticyclone and its impact on sea surface temperature off north-central Chile

Cited by 67 publications

References 37 publications

Contribution of Ekman pumping to the changes in properties and volume of the Eastern South Pacific Intermediate Water

Contribution of Ekman pumping to the changes in properties and volume of the Eastern South Pacific Intermediate Water

Seasonal variability of the oxygen minimum zone off Peru in a high-resolution regional coupled model

Context‐dependent functional dispersion across similar ranges of trait space covered by intertidal rocky shore communities

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