Warming in the Agulhas Current system since the 1980's
International audience; Since the 1980's, the sea surface temperature of the Agulhas Current system has increased significantly. The warming is due to an augmentation of its transport in response to an increase in wind stress curl in the South Indian Ocean at relevant latitudes. This causes an increase in the fluxes of salt and heat into the Atlantic Ocean and in the transfer of energy from the ocean to the atmosphere. Therefore, the changes we are witnessing in the region could have far reaching consequences on top of the regional impacts on ecosystem and climate. The increase in wind stress curl is consistent with a poleward shift of westerly wind in the Southern Hemisphere reported by ot…
On the recent warming of the Agulhas Current
The Agulhas Current is an energetic current driven by the wind field over the Indian Ocean. It has a profound effect on the climate and the coastal ecosystem of South Africa and plays a key role in the global ocean circulation. The current carries warm and salty water from the tropics polewards and controls the exchange of heat and salt between the Indian and Atlantic Oceans. Since the 1980s, the sea surface temperature of the Agulhas Current system has increased significantly. This is due to an increase of its transport in response to an augmentation in wind stress curl in the South Indian Ocean. This causes an intensification of the Agulhas Current system and leads to an increased flux of…
Coastal Oceanic climate change and variability from 1982 to 2009 around South Africa
Changes and fluctuations in sea surface temperature (SST) around the South African coast are analysed at a monthly scale from 1982 to 2009. There is a statistically significant negative trend of up to 0.5 °C per decade in the southern Benguela from January to August, and a cooling trend of lesser magnitude along the South Coast and in the Port Elizabeth/Port Alfred region from May to August. The cooling is due to an increase in upwelling-favourable south-easterly and easterly winds. There is a positive trend in SST of up to 0.55 °C per decade in most parts of the Agulhas Current system during all months of the year, except for KwaZulu-Natal where warming is in summer. The warming was attri…