Intercomparison of Heat Fluxes in the South Atlantic. Part I: The Seasonal Cycle

Abstract

Intercomparison of the seasonal cycle for the fluxes of sensible and latent heat for four observation-based products [DaSilva, NCEP, Esbensen?Kushnir (EK), and the Southampton Oceanography Centre (SOC)] and the results for the NCAR Community Climate System Model (CCSM) are examined in order to gain an improved understanding of the South Atlantic characteristic spatial patterns. Their seasonal structure associated with ocean dynamics, evolution, and the net heat flux patterns are also discussed. The key regions of the Brazil?Malvinas confluence, Agulhas retroflection, and Benguela upwelling region off Africa were chosen for a closer examination of the fluxes. All climatologies show very different behavior. The SOC product presents sudden changes in the seasonal cycle evolution, departing from the annual or semiannual observed pattern of EK and NCEP. Compared to the other climatologies, EK shows equivalent temporal behavior but different magnitudes because this climatology covers a period where much less data was available. It was found that the eastern Atlantic shows more differences among the climatologies than the Brazil?Malvinas confluence region in the west. It is also in the eastern Atlantic that the difference between NCAR CCSM results and observations are bigger, probably due to a bias in cloud simulation, which affects the air?sea interaction dynamics. In the Brazil?Malvinas confluence region differences between the NCAR CCSM and the observed datasets are comparable to the difference between the observations themselves.