Disentangling the Driving Mechanisms of the Tripole Mode of Summer Rainfall over Eastern China

Abstract The spatial distribution of summer rainfall anomalies over eastern China often shows a tripole pattern with the Yangtze River basin varies in opposite phase North and South China. It is not clear whether this an intrinsic atmospheric mode or it remotely forced. Using two sets model outputs from 20 models participating 5 Coupled Model Intercomparison Project (CMIP5), paper investigates driving mechanisms leading its major influencing factors. One set (piControl) fully coupled atmosphere–ocean simulations under constant preindustrial forcing other (sstClim) atmosphere-alone forced by prescribed climatological sea surface temperatures (SSTs). By comparing results these different simulations, found that precipitation variability without oceanic forcing. can be regarded as although air–sea interaction modify temporal variability. cyclonic–anticyclonic circulation anomaly northern Pacific identified key factor both experiments. As internal variability, related to circumglobal zonal wave train propagating along westerly jet stream. When interactions involved, modulation SST exerted through meridional Pacific–Japan/East Asia–Pacific East Asian coast. Our suggest could another region providing potential predictability monsoon addition Indo-Pacific.