Fundamental challenge in simulation and prediction of summer monsoon rainfall

The scientific basis for two‐tier climate prediction lies in the predictability determined by the ocean and land surface conditions. Here we show that the state‐of‐the‐art atmospheric general circulation models (AGCMs), when forced by observed sea surface temperature (SST), are unable to simulate properly Asian‐Pacific summer monsoon rainfall. All models yield positive SST‐rainfall correlations in the summer monsoon that are at odds with observations. The observed lag correlations between SST and rainfall suggest that treating monsoon as a slave possibly results in the models' failure. We demonstrate that an AGCM, coupled with an ocean model, simulates realistic SST‐rainfall relationships; however, the same…