Remote effect of the model cold bias in the tropical North Atlantic on the warm bias in the tropical southeastern Pacific

Most state-of-the-art climate models show significant systematic biases in the tropical southeastern Pacific (SEP) and tropical North Atlantic (TNA). These biases manifest themselves as the sea surface temperature (SST) in the SEP being too warm and the SST in the TNA being too cold. That is, as the cold SST biases appear in the TNA, the warm SST biases also occur in the SEP. This indicates that if climate models cannot succeed in simulating the TNA variability, they will also fail at least partially in the SEP. Our coupled model experiments show that the cold SST bias in the TNA results in a weakening of the Hadley-type circulation from the TNA to the SEP. This meridional circulation reduces the South Pacific subtropical anticyclone and the associated subsidence, which in turn leads to a reduction of low clouds, a weakening of the easterly trade wind, and thus an increase of the warm SST bias in the SEP.