Head of the Research Unit:
GEOMAR Helmholtz Centre for Ocean Research Kiel
East shore campus
Phone: +49-431 600-4101
Phone: +49-431 600-4288
PREFACE aims at a better understanding of the physical processes driving today's climate in the Tropical Atlantic. Understanding the interaction of the atmosphere and ocean in the Tropical Atlantic region is key to accurately project the future climate for the Tropical Atlantic region as well as the global climate. In the framework of PREFACE a quantification of the cumulative effects of climate variability, greenhouse-induced climate change and fisheries on marine ecosystems and functional diversity is aspired. Furthermore, one objective is to assess socio-economic vulnerabilities of the West-African fishing communities and evaluate their resilience to climate-driven ecosystem shifts and global markets.
WP4 aims at improving our understanding of the role of local and remote forcings, such as circulation variability or wave propagation along the equatorial and coastal wave-guide, in setting the mean sea surface temperature pattern and in driving sea surface temperature variability in the eastern boundary coastal upwelling regions of both hemispheres. The sea surface temperature variability in the eastern equatorial Atlantic is forced by different processes: Year-to-year variations are associated with air-sea interactions (including the positive Bjerknes feedback) similar to processes resulting in the El Niño phenomenon of the equatorial Pacific (the so-called Atlantic Niño), by advection and wave dynamics as well as by internal variability associated with stochastic processes due to variations in the intensity of tropical instability waves or basin-mode oscillations associated with the generation of equatorial deep jets. The equatorial variability was found to be strongly related to the generation of Benguela Niños, warm oceanic events in the southeastern tropical and subtropical Atlantic (Rouault, 2012).
However, local forcing of sea surface temperature variability in the coastal upwelling regimes of both hemispheres might be as important. In the southern hemisphere south of about 13°S, coastal upwelling is strongly related to variations in along-shore winds, north of it upwelling also occurs during periods of calm winds possibly induced by coastal Kelvin wave propagation.
The specific objectives of WP4 are as follows: