Sea surface temperature in False Bay (South Africa): Towards a better understanding of its seasonal and inter-annual variability

Two sea surface temperature (SST) products, Pathfinder version 5.0 and MODIS/TERRA are evaluated and used to study the seasonal and the inter-annual variability of sea surface temperature (SST) together with local SST and wind data in the vicinity of False Bay (Western Cape, South Africa). At the monthly scale, differences of up to 3 °C are detected between the two products in the bay. In the northern half of the bay, SST is fairly well explained by seasonality. In contrast, the southern half exhibits a higher inter-annual variability in SST. The southern half of the bay and the Western Cape upwelling system (Cape Agulhas to Cape Columbine) share most of their variance. Furthermore, the inter-annual variability of SST in False Bay is correlated with both the Niٌo 3.4 index and local wind speed anomalies. El Niٌo (La Niٌa) events induce an equatorward (poleward) shift in the South Atlantic High pressure system leading to a weakening (strengthening) of upwelling favourable south-easterly. Those changes induce a warm (cold) SST anomaly along the West Coast of Southern Africa.