Amplified East China precipitation related to East Asia-Pacific teleconnection due to preceding circumglobal teleconnection on quasi-biweekly timescale

The East Asia-Pacific (EAP) teleconnection is the dominant pattern along the East Asian coast during summer, playing a crucial role in modulating precipitation variability and extreme rainfall events over East China. This study investigates the precipitation anomalies in East China associated with the quasi-biweekly (QBW) EAP teleconnection, as well as the influence of preceding circumglobal teleconnections (CGT) on these anomalies. During QBW EAP events, the enhanced precipitation gradually shifts from Southeast China to the Yangtze River Valley and eventually diminishes over the Yellow River Valley. Notably, the QBW EAP events preceded by the negative phase of CGT exhibit substantially more intense, extensive, and persistent precipitation anomalies, accompanied by a higher probability of extreme precipitation events, compared with those preceded by the positive or neutral phase of CGT. The cause of such amplified precipitation was examined by moisture static energy (MSE) budget diagnosis. The MSE recharge process associated with the increasing precipitation can be divided into two substages. Firstly, the negative CGT pattern leads to anomalous upper-level descent over East China, which enhances MSE vertical advection and suppresses vigorous convection, triggering a rapid recharge of MSE. Secondly, the upstream warming and internal energy advection associated with the negative CGT significantly sustain the MSE recharge, leading to amplified and prolonged precipitation. These results highlight the effects of the preceding negative CGT on the QBW EAP-related precipitation via the upper-tropospheric circulation affecting local MSE dynamics. Our finding offers insights that could potentially enhance the predictive capabilities of high-impact rainfall events in East China.