Table of Contents
International Journal of Oceanography
Volume 2015 (2015), Article ID 510713, 8 pages
http://dx.doi.org/10.1155/2015/510713
Research Article

Relation between Upwelling Intensity and the Variability of Physical and Chemical Parameters in the Southern Benguela Upwelling System

1Department of Environmental Affairs, Oceans and Coasts, Private Bag Box X2, Cape Town 8012, South Africa
2Cape Peninsula University of Technology, P.O. Box 1906, Bellville 7535, South Africa

Received 13 November 2014; Revised 29 December 2014; Accepted 31 December 2014

Academic Editor: Swadhin Behera

Copyright © 2015 Hassan Ebrahiem Ismail et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The extent to which wind-driven seasonal upwelling cycles manifest in surface ocean temperature and nutrient variability along a monitoring line in the Southern Benguela upwelling system was investigated. Monitoring conducted monthly over a six-year period shows that surface temperature and nutrient concentrations exhibit very poor seasonality and weak correlation with the upwelling index. This is, despite clear evidence for spatial inshore-offshore gradients in temperature, nutrients, and chlorophyll, consistent with an upwelling regime. The upper ocean temperature gradient shows a much better correspondence to the upwelling index but at the same time demonstrates that surface heating, and not vertical mixing related to upwelling, controls the upper ocean temperature gradient. The results suggest that remote sensing techniques would be inadequate tools to monitor upwelling events in the Southern Benguela. Also, the incidence of phytoplankton blooms is more likely triggered by stratified conditions associated with surface heating than relaxation of upwelling winds.