Multi-Decadal Variations in the Southeastern Atlantic Climate

Abstract:

High-resolution observations along with atmospheric and oceanic reanalyses are diagnosed to understand how the southeastern Atlantic climate has changed over the 1982 – 2013 period. Multiple datasets are used to evaluate confidence. Two large-scale circulation changes are identified as being important mechanisms for influencing the multi-decadal climate variability. The first change is a significant poleward shift of the South Atlantic anticyclone, which is consistent with the observed poleward expansion of the Tropics. The second change is an intensification of the continental thermal low over southwestern Africa, which is associated with an amplified warming effect over the Kalahari Desert. The impact of these circulation changes on the multi-decadal precipitation variability and South Atlantic SST trends is explored here. The findings from this study suggest that a better understanding of South Atlantic subtropical anticyclone and continental thermal low interactions is crucial to better understand regional climate variability associated with global warming over the South Atlantic.