Contour interval of the meridional SST gradient is 0.2 °C/°.
Ocean circulation, upwelling and turbulent heat flux errors all modulate the intensity and the seasonality of the ABFZ errors.).
In particular, the climatological Inter-tropical Convergence Zone (ITCZ) is shifted southward with erroneously intense rainfall over the equator, surface trade winds and equatorial upwelling are too weak, and the thermocline is too deep in the eastern Atlantic; (e.g., Tozuka et al.
) that a westerly wind bias over the western equatorial Atlantic in spring (March–April–May, hereafter MAM) depresses the ocean thermocline in the eastern Atlantic, preventing, the development of an Atlantic cold tongue (ACT, Vizy and Cook ).
The equatorial warm SST bias is most intense in boreal summer (JJA, not shown) during the West Africa Monsoon season.
The timing is consistent with previous studies (e.g., Richter ), Nor ESM has a large warm SST bias in the eastern tropical Atlantic that reaches 4 °C at the equator and 8 °C off the southwestern African coast.