Spatial and temporal seasonal trends in coastal upwelling off Northwest Africa, 1981-2012

Cropper, Thomas E., Hanna, Edward and Bigg, Grant R. 2014. Spatial and temporal seasonal trends in coastal upwelling off Northwest Africa, 1981-2012. Deep Sea Research Part I: Oceanographic Research Papers 86 , pp. 94-111. 10.1016/j.dsr.2014.01.007

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (3MB) | Preview

Abstract

Seasonal coastal upwelling was analyzed along the NW African coastline (11–35°N) from 1981 to 2012. Upwelling magnitudes are calculated by wind speed indices, sea-surface temperature indices and inferred from meteorological station, sea-surface height and vertical water column transport data. A permanent annual upwelling regime is documented across 21–35°N and a seasonal regime across 12–19°N, in accordance with the climatology of previous studies. Upwelling regions were split into three zones: (1) the Mauritania–Senegalese upwelling zone (12–19°N), (2) the strong permanent annual upwelling zone (21–26°N) and (3) the weak permanent upwelling zone (26–35°N). We find compelling evidence in our various indices for the Bakun upwelling intensification hypothesis due to a significant coastal summer wind speed increase, resulting in an increase in upwelling-favorable wind speeds north of 20°N and an increase in downwelling-favorable winds south of 20°N. The North Atlantic Oscillation plays a leading role in modifying interannual variability during the other seasons (autumn–spring), with its influence dominating in winter. The East Atlantic pattern shows a strong correlation with upwelling during spring, while El Niño Southern Oscillation and Atlantic Multi-decadal Oscillation teleconnections were not found. A disagreement between observationally-based wind speed products and reanalysis-derived data is explored. A modification to the Bakun upwelling intensification hypothesis for NW Africa is presented, which accounts for the latitudinal divide in summer wind regimes

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	Elsevier
ISSN:	0967-0637
Date of First Compliant Deposit:	9 June 2016
Date of Acceptance:	30 January 2014
Last Modified:	06 May 2023 07:57
URI:	https://orca.cardiff.ac.uk/id/eprint/91581

Citation Data

Cited 159 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item