On the existence of an El Niño-type phenomenon in the Benguela System

Shannon, L. V.; Boyd, A. J.; Brundrit, G. B.; Taunton-Clark, J.

doi:10.1357/002224086788403105

Cited by 271 publications

(215 citation statements)

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“…In addition, altimetry and regional ocean simulations revealed equatorial forced CTWs having interannual time scales (13-20 months; Bachèlery et al 2016). Along the Angolan and Namibian continental margin, CTWs contribute to triggering sea surface temperature (SST) anomalies, which impact atmospheric circulation and rainfall (Shannon et al 1986;Rouault et al 2003;Imbol Koungue et al 2017;Rouault et al 2018). CTWs may also modulate biogeochemical conditions in the coastal upwelling ecosystems and directly impact fisheries by displacing fish eggs and larvae latitudinally along the continental margin (e.g., Ostrowski 2007).…”

Section: History Of Physical Oceanography In Angolamentioning

confidence: 99%

Eastern Boundary Circulation and Hydrography Off Angola: Building Angolan Oceanographic Capacities

Tchipalanga

Dengler

Brandt

et al. 2018

Bulletin of the American Meteorological Society

122

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The eastern boundary region off Angola encompasses a highly productive ecosystem important for the food security of the coastal population. The fish-stock distribution, however, undergoes large variability on intraseasonal, interannual, and longer time scales. These fluctuations are partly associated with large-scale warm anomalies that are often forced remotely from the equatorial Atlantic and propagate southward, reaching the Benguela upwelling off Namibia. Such warm events, named Benguela Niños, occurred in 1995 and in 2011. Here we present results from an underexplored extensive in situ dataset that was analyzed in the framework of a capacity-strengthening effort. The dataset was acquired within the Nansen Programme executed by the Food and Agriculture Organization of the United Nations and funded by the Norwegian government. It consists of hydrographic and velocity data from the Angolan continental margin acquired biannually during the main downwelling and upwelling seasons over more than 20 years. The mean seasonal changes of the Angola Current from 6° to 17°S are presented. During austral summer the southward Angola Current is concentrated in the upper 150 m. It strengthens from north to south, reaching a velocity maximum just north of the Angola Benguela Front. During austral winter the Angola Current is weaker, but deeper reaching. While the southward strengthening of the Angola Current can be related to the wind forcing, its seasonal variability is most likely explained by coastally trapped waves. On interannual time scales, the hydrographic data reveal remarkable variability in subsurface upper-ocean heat content. In particular, the 2011 Benguela Niño was preceded by a strong subsurface warming of about 2 years’ duration.

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Section: History Of Physical Oceanography In Angolamentioning

confidence: 99%

Eastern Boundary Circulation and Hydrography Off Angola: Building Angolan Oceanographic Capacities

Tchipalanga

Dengler

Brandt

et al. 2018

Bulletin of the American Meteorological Society

122

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“…The northern Benguela system is subjected to large-scale environmental variability, which originates in the tropics and is similar to the El Niño phenomenon in the Pacific Ocean. These major environmental anomalies, termed Benguela Niños, have severe biological effects at all levels of the marine foodweb (Shannon et al 1986, Gammelsrød et al 1998, Roux 2003.…”

Section: Biological and Historical Backgroundmentioning

confidence: 99%

Ecosystem approach to fisheries management in the northern Benguela: the Namibian experience

Roux¹,

Shannon²

2004

African Journal of Marine Science

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“…Major southward frontal shifts have been observed during warm events in the tropical South East Atlantic Ocean, such as Benguela Niños [Shannon et al, 1986;Veitch et al, 2006]. On time scales up to millennia, [Kim et al, 2003] found evidence of thermal gradient changes of the front due to changes in the intensity of the trade wind system.…”

Section: Introductionmentioning

confidence: 99%

A model study of the Angola Benguela Frontal Zone: Sensitivity to atmospheric forcing

Colberg

Reason

2006

Geophysical Research Letters

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A regional ocean model is applied to the tropical South East Atlantic Ocean in order to investigate the sensitivity of the intensity and position of the Angola Benguela Frontal Zone. The results suggest that the position of the Angola Benguela Frontal Zone is mainly determined by opposing northward and southward flow within 2 degrees off the coast. The windstress curl plays a major role in altering the position of the Angola Benguela Frontal Zone, as it controls the southeastward flow of the South Equatorial Counter Current. The opposing northward flow is mainly the result of geostrophic adjustment to coastal upwelling driven by the meridional windstress. The strength of the frontal zone is found to be related to the strength of the southerly windstress that controls the coastal upwelling.

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On the existence of an El Niño-type phenomenon in the Benguela System

Cited by 271 publications

References 0 publications

Eastern Boundary Circulation and Hydrography Off Angola: Building Angolan Oceanographic Capacities

Eastern Boundary Circulation and Hydrography Off Angola: Building Angolan Oceanographic Capacities

Ecosystem approach to fisheries management in the northern Benguela: the Namibian experience

A model study of the Angola Benguela Frontal Zone: Sensitivity to atmospheric forcing

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