Connections between the South Asian summer monsoon and the tropical sea surface temperature in CMIP5

The South Asian summer monsoon (SASM) precipitation is analyzed based on reanalysis datasets and historical simulation results from 23 climate models of the Coupled Model Intercomparison Project phase 5 (CMIP5). The results show that most models reproduce well the climatological pattern of SASM precipitation, but the main rainfall period lags that of the reanalysis by one month. The relationship between the simulated SASM precipitation and sea surface temperature anomalies (SSTAs) is quite similar to the reanalysis data. This is attributed to the well-reproduced Walker cell anomaly in the tropical zone. It is projected that the negative correlation between SASM precipitation and SSTAs in the eastern equatorial Pacific will weaken and even reverse to a positive one in the period 2070–2096 under the representative concentration pathway (RCP) scenario with strong external forcing (RCP8.5), while the change of the correlation under moderate forcing (RCP4.5) still has great uncertainty.