The north-east North Atlantic Tripole implicated as a predictor of the August precipitation decadal variability over north China

Monthly precipitation over north China in August (NCAP) is the second highest in the year, and it is important to understand its driving mechanisms to facilitate reliable forecasting. The NCAP displays a significant decadal variability of a cycle about 10-year and negatively correlates with the July north-east North Atlantic Tripole (NAT) over the decadal timescales. This study shows that the Eurasian decadal teleconnection (EAT) acts as a bridge that links the July NAT with NCAP decadal variability. This coupled ocean-atmosphere bridge (COAB) mechanism, through which the July NAT influences the decadal variability of NCAP, can be summarized as follows. The cumulative effect of the NAT drives the EAT to adjust atmospheric circulation over north China and the surrounding regions, and so regulates precipitation in north China by influencing local water vapor transport. When the July NAT is in a negative (positive) phase, the EAT pattern has a positive (negative) pattern, which promotes (weakens) the transmission of water vapor from the sea in the south-east to north China, thus increasing (decreasing) NCAP over decadal timescales. The decadal NCAP model established based on the July NAT can effectively predict the NCAP decadal variability, illustrating that the July NAT can be implicated as a predictor of the NCAP decadal variability.