1997–1998 El Niño off Peru: A numerical study

Colas, François; Capet, Xavier; McWilliams, James C.; Shchepetkin, Alexander F.

doi:10.1016/j.pocean.2008.10.015

Cited by 93 publications

(94 citation statements)

References 49 publications

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“…Our results show that compensation of coastal upwelling by cross-shore geostrophic currents is an important process, which needs to be taken into account [Colas et al, 2008;Marchesiello and Estrade, 2010]. In all of our simulations, the onshore geostrophic velocity plays an important role all year round and compensates up to one third of the Ekman transport ( Figure 11).…”

Section: Discussionmentioning

confidence: 76%

“…We first study the seasonal evolution of cross-shore transport in a coastal band, which can be considered as a proxy of coastal upwelling, following Colas et al [2008]. For each month, we calculate the mean horizontal transport in a coastal strip extending from 7 S to 13 S and from 40 km (two model grid points from the coast) to 160 km (eight model grid points from the coast) offshore.…”

Section: Cross-shore Mass Balancementioning

confidence: 99%

“…The mass balance is verified, as U tot $U Ek 1U G . Ekman transport overestimates total cross-shore transport by up to 40% in the annual means, due to a compensation by the shoreward geostrophic crossshore transport U G in the Ekman layer, as described by Colas et al [2008] during El Niño events and by Marchesiello and Estrade [2010] in a more general context.…”

Section: Cross-shore Mass Balancementioning

confidence: 99%

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Peru‐Chile upwelling dynamics under climate change

et al. 2015

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The consequences of global warming on the Peru-Chile Current System (PCCS) ocean circulation are examined with a high-resolution, eddy-resolving regional oceanic model. We performed a dynamical downscaling of climate scenarios from the IPSL-CM4 Coupled General Circulation Model (CGCM), corresponding to various levels of CO 2 concentrations in the atmosphere. High-resolution atmospheric forcing for the regional ocean model are obtained from the IPSL atmospheric model run on a stretched grid with increased horizontal resolution in the PCCS region. When comparing future scenarios to preindustrial (PI) conditions, the circulation along the Peru and Chile coasts is strongly modified by changes in surface winds and increased stratification caused by the regional warming. While the coastal poleward undercurrent is intensified, the surface equatorial coastal jet shoals and the nearshore mesoscale activity are reinforced. Reduction in alongshore wind stress and nearshore wind stress curl drive a year-round reduction in upwelling intensity off Peru. Modifications in geostrophic circulation mitigate this upwelling decrease in late austral summer. The depth of the upwelling source waters becomes shallower in warmer conditions, which may have a major impact on the system's biological productivity.

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Section: Discussionmentioning

confidence: 76%

Section: Cross-shore Mass Balancementioning

confidence: 99%

Section: Cross-shore Mass Balancementioning

confidence: 99%

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Peru‐Chile upwelling dynamics under climate change

et al. 2015

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“…The physical model ROMS has been used in several previous works to simulated the dynamics of the HCLME (Penven et al 2005, Colas et al 2008, Montes et al 2010, Echevin et al 2012, Illig et al 2014.…”

Section: Pisces Biogeochemical Model-mentioning

confidence: 99%

Biogeochemical validation of an interannual simulation of the ROMS-PISCES coupled model in the Southeast Pacific

et al. 2016

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TRABAJOS ORIGINALES© Los autores. Este artículo es publicado por la Revista Peruana de Biología de la Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos. Este es un artículo de acceso abierto, distribuido bajo los términos de la Licencia Creative Commons Atribución-NoComercial-CompartirIgual 4.0 Internacional.(http://creativecommons.org/licenses/by-nc-sa/4.0/), que permite el uso no comercial, distribución y reproducción en cualquier medio, siempre que la obra original sea debidamente citadas. Para uso comercial, por favor póngase en contacto con editor.revperubiol@gmail.com. Información sobre los autores:DEM redactó el trabajo y analizó los datos. VE y ROR analizaron los datos. JTM redactó el trabajo. JLR y JRF ayudaron en la recolección de datos. CRT contribuyó en la discusión en el trabajo.Los autores no incurren en conflictos de intereses. Presentado:31/07/2015 Aceptado:08/06/2016 Publicado online: 27/08/2016 AbstractCurrently biogeochemical models are used to understand and quantify key biogeochemical processes in the ocean. The objective of the present study was to validate predictive ability of a regional configuration of the PISCES biogeochemical model on main biogeochemical variables in Humboldt Current Large Marine Ecosystem (HCLME). The statistical indicators used to evaluate the model were the bias, root-mean-square error, correlation coefficient and, graphically, the Taylor's diagram. The results showed that the model reproduces the dynamics of the main biogeochemical variables (chlorophyll, dissolved oxygen and nutrients); in particular, the impact of El Niño 1997-1998 in the chlorophyll (decrease) and oxygen minimum zone depth (increase). However, it is necessary to carry out sensitivity studies of the PISCES model with different key parameters values to obtain a more accurate representation of the properties of the Ocean. Keywords: PISCES model; HCLME; chlorophyll; dissolved oxygen; nutrients. ResumenLos modelos biogeoquímicos en la actualidad son utilizados para entender y cuantificar los principales procesos biogeoquímicos que suceden en el océano. El objetivo del presente estudio es validar estadísticamente la habilidad predictiva de una simulación del modelo biogeoquímico PISCES en reproducir la dinámica de las principales variables biogeoquímicas del Ecosistema de la Corriente de Humboldt (ECH). Para evaluar el modelo se utilizaron indicadores estadísticos: sesgo, error de la raíz del cuadrado medio, coeficiente de correlación y gráficamente el diagrama de Taylor. Los resultados muestran que el modelo es capaz de reproducir la dinámica de las principales variables biogeoquímicas (clorofila, oxígeno disuelto y nutriente), captando bien el impacto que tiene El Niño 1997-1998 en la clorofila (disminución) y profundidad de la zona mínima de oxígeno (incremento). Es necesario llevar a cabo estudios de sensibilidad del modelo PISCES usando diferentes valores de los principales parámetros para obtener una mejor representación de las propiedades biogeoquímicas del océano.Pala...

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“…In the HCS, SST is affected by both the wind-induced upwelling and the heat fluxes at the air-sea interface (e.g., [24][25][26][27]). The propagation of coastal-trapped waves (CTW) also plays a role in the SST variability [24,28], in particular during El Niño Southern Oscillation (ENSO) events [29,30]. The imprint of CTWs is strong in the Northern HCS, but off Central Chile (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) • S) their amplitude is largely attenuated so that the SST can be inferred from a one-dimensional model forced by the local wind stress and solar heating [24].…”

Section: Introductionmentioning

confidence: 99%

Coastal Upwelling Front Detection off Central Chile (36.5–37°S) and Spatio-Temporal Variability of Frontal Characteristics

et al. 2018

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Abstract:In Eastern Boundary Upwelling Systems, cold coastal waters are separated from offshore by a strong cross-shore Sea Surface Temperature (SST) gradient zone. This upwelling front plays a major role for the coastal ecosystem. This paper proposes a method to automatically identify the front and define its main characteristics (position, width, and intensity) from high resolution data. The spatio-temporal variability of the front characteristics is then analyzed in a region off Central Chile (37 • S), from 2003 to 2016. The front is defined on daily 1 km-resolution SST maps by isotherm T 0 with T 0 computed from mean SST with respect to the distance from the coast. The probability of detecting a front, as well as the front width and intensity are driven by coastal wind conditions and increased over the 2007-2016 period compared to the 2003-2006 period. The front position, highly variable, is related to the coastal jet configuration and does not depend on the atmospheric forcing. This study shows an increase by 14% in the probability of detecting a front and also an intensification by 17% of the cross-front SST difference over the last 14 years. No trend was found in the front position.

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1997–1998 El Niño off Peru: A numerical study

Cited by 93 publications

References 49 publications

Peru‐Chile upwelling dynamics under climate change

Peru‐Chile upwelling dynamics under climate change

Biogeochemical validation of an interannual simulation of the ROMS-PISCES coupled model in the Southeast Pacific

Coastal Upwelling Front Detection off Central Chile (36.5–37°S) and Spatio-Temporal Variability of Frontal Characteristics

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