Coastal upwelling at Cape Frio: Its structure and weakening

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TitleCoastal upwelling at Cape Frio: Its structure and weakening
Publication TypeJournal Article
Year of Publication2017
AuthorsJury, MR
JournalCONTINENTAL SHELF RESEARCH
Volume132
Pagination19-28
Date PublishedJAN 1
Type of ArticleArticle
ISSN0278-4343
KeywordsAfrica, Cape Frio, Coastal upwelling, Warming trend
AbstractCape Frio at the Angola-Namibia border, is the northern-most coastal upwelling cell of the Benguela Current (similar to 17S, 11E) and is sensitive to climate variability. This study provides new insights using daily high resolution satellite and ocean-atmosphere reanalysis datasets in the period 1985-2015. The annual cycle of SST follows two months behind the net heat balance and wind stress curl, reaching a minimum in July-September. Ranking the daily SST record, two intense multi-day upwelling events stand out. The more recent case of 26-29 August 2005 is studied, given the greater density and sophistication of satellite data. A coastal wind jet > 10 m s(-1) develops next to Cape Frio, with sharp edges imposed by a thermal inversion and the mountainous cape. The cold plume < 14C west of Cape Frio is co-located with cyclonic wind stress curl and downward heat fluxes. Leeward of Cape Frio, a wind shadow and poleward currents contribute to phytoplankton blooms. Daily time series 1985-2015 reveal warming SST +.035C/yr and diminishing winds -0.025 m s(-1)/yr. The trend toward cyclonic winds over Angola and the northern Benguela Current reflects a poleward and offshore shift of the main axis of southeasterly winds.
DOI10.1016/j.csr.2016.11.009