Subtropical clouds key to Southern Ocean teleconnections to the tropical Pacific

Global climate models suffer from common errors of excessive precipitation over the southeastern tropical Pacific. This tropical precipitation bias limits the skill of model simulations and the confidence in future climate projections. While the underestimated subtropical low clouds typically are considered the main culprit of the tropical precipitation bias, more recent studies propose the overly warm Southern Ocean as another possible cause, but models disagree on the quantitative importance of this remote contribution. Here, we show the Southern Ocean-driven teleconnection mechanism mediated by subtropical low cloud feedback, which is erroneously weak in climate models. This suggests that the impact of the Southern Ocean bias on the tropical precipitation bias is likely to be stronger than recent studies suggest.