Affiliation:
1. a Nansen Tutu Center for Marine Environmental Research, Department of Oceanography, University of Cape Town, Cape Town, South Africa
Abstract
Abstract
The impact of El Niño–Southern Oscillation (ENSO) on the southern African climate is well documented and provides skill in the seasonal forecast of rainfall, but less is known about the impact of ENSO on the Benguela Current west of southern Africa. There is a significant weak correlation between ENSO and the Benguela Current upwelling sea surface temperature (SST) in austral summer. Correlation is positive for southern Benguela and negative for northern Benguela. A significant correlation exists with up to 8 months lag when ENSO leads. The impact of ENSO is due to weaker-than-normal upwelling favorable southeasterly winds during El Niño in southern Benguela, leading to warmer-than-normal coastal SST. In contrast, during La Niña, stronger-than-normal southeasterly winds lead to cooler-than-normal SST. The opposite effect applies to northern Benguela. The coastal wind change is part of an ENSO large-scale basinwide perturbation in the tropical and South Atlantic. However, non-ENSO-related SST variation in the Benguela upwelling can be as important as ENSO-related SST perturbation, and some ENSO events do not lead to the expected changes. Changes in the Benguela upwelling are linked to changes in the intensity of the trade winds associated with a change of the South Atlantic anticyclone intensity and position. In southern Benguela, changes are also associated with variations in midlatitude low pressure systems and associated upwelling unfavorable westerly winds. La Niñas favor the development of Benguela Niños in Angola and Namibia. This study shows the potential for SST seasonal predictability in the Benguela upwelling due to the leading lag correlation between ENSO and the Benguela upwelling SST.
Funder
Horizon 2020 Framework Programme
National Research Foundation
Publisher
American Meteorological Society
Reference41 articles.
1. Teleconnections in the atmosphere;An, S.,2020
2. Interannual coastal trapped waves in the Angola-Benguela upwelling system and Benguela Niño and Niña events;Bachèlery, M.-L.,2020
3. Subtropical SST dipole events in the southern Indian Ocean;Behera, S. K.,2001
4. Ecosystem change in the southern Benguela and the underlying processes;Blamey, L. K.,2015
5. Atmosphere–ocean interactions;Chang, P.,2020
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献