Capacitor effect of North Pacific on bridging the spring Tibetan Plateau heating anomaly and East Asian summer monsoon

The East Asian summer monsoon (EASM) arises from complex land-air-sea interactions, shaped by influences from the Tibetan plateau to the west and the Pacific ocean to the east. Using in situ observations, reanalysis data and simulations from the Community Earth System Model version 2.1.3, here we show that North Pacific sea surface temperature anomalies (SSTAs) act as a seasonal capacitor, mediating the delayed impact of spring Tibetan Plateau surface sensible heating (TPSH) anomalies on EASM. Enhanced spring TPSH excites Rossby waves that drives an anticyclonic circulation, establishing a persistent "warm-central/cold-flanks" SSTA pattern in the North Pacific. These SSTAs strengthen summer subtropical front and atmospheric baroclinicity, energizing transient eddies. The resultant cyclonic-anticyclonic circulation anomalies enhance low-level moisture convergence, intensifying rainfall from the Yangtze-Huaihe River basin to southeastern Japan. This capacitor effect facilitates a cross-seasonal linkage by converting spring-initiated TPSH anomalies into basin-scale summer circulation adjustments through oceanic thermal inertia-driven storage.

东亚夏季风（East Asian summer monsoon, EASM）起源于复杂的陆-气-海相互作用，其形成受西侧青藏高原与东侧太平洋的共同调控。本研究利用原位观测（in situ observations）、再分析资料（reanalysis data）以及社区地球系统模型版本2.1.3（Community Earth System Model version 2.1.3）的模拟结果，证实北太平洋海表温度异常（sea surface temperature anomalies, SSTAs）扮演着季节电容器（seasonal capacitor）的角色，介导了春季青藏高原地表感热加热（Tibetan Plateau surface sensible heating, TPSH）异常对东亚夏季风的延迟影响。春季增强的TPSH会激发罗斯贝波（Rossby waves），驱动反气旋环流（anticyclonic circulation）形成，并在北太平洋建立持续的"暖中心-冷侧翼"型SSTA分布。这些SSTA会增强夏季副热带锋面（subtropical front）与大气斜压性（atmospheric baroclinicity），激活瞬变涡旋（transient eddies）活动。由此产生的气旋-反气旋环流异常会增强低层水汽辐合（low-level moisture convergence），加剧从江淮流域（Yangtze-Huaihe River basin）到日本东南部的降水过程。该季节电容器效应借助海洋热惯性（thermal inertia）驱动的信号储存过程，将春季初始形成的TPSH异常转化为海盆尺度的夏季环流调整，从而构建起跨季节的关联链路。