Over the past two decades, there has been a significant shift in tropical cyclone (TC) activity in the western North Pacific (WNP) basin during the boreal summer. Our analysis of data spanning from 1979 to 2021 reveals significant shifts in the WNP TC characteristics and rainfall pattern variation. To deepen our understanding of TC-related precipitation dynamics, we expressly address the difference between TC-related core precipitation (TCP) and remote precipitation (TRP). The results show that TRP significantly impacts the East Asian (EA) continent, especially on the Korean Peninsula. Notably, TCP exhibits decadal variability, with a pronounced negative correlation identified between it and the Pacific decadal oscillation (PDO) following a strong climate shift. This pivotal shift was marked by the PDO first transitioning to its negative phase in 1997, a notable change since 1979, resulting in a marked increase in TC-related extreme rainfall over the EA area. Concurrently, the rising sea surface temperatures (SSTs) over the WNP have intensified the western Pacific subtropical high (WPSH) circulation. The easterly steering flow associated with the WPSH then strengthened, leading to the continental migration of TC trajectories, thereby intensifying TC-related extreme precipitation.

中文翻译：

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北半球夏季期间东亚地区与 WNP 热带气旋相关的极端降水增加，与 PDO 变化相关


过去二十年来，北半球夏季期间西北太平洋（WNP）盆地的热带气旋（TC）活动发生了显着变化。我们对 1979 年至 2021 年数据的分析揭示了 WNP TC 特征和降雨模式变化的显着变化。为了加深我们对与 TC 相关的降水动态的理解，我们明确讨论了与 TC 相关的核心降水（TCP）和远程降水（TRP）之间的差异。结果表明，TRP对东亚大陆，特别是朝鲜半岛影响显着。值得注意的是，TCP 表现出年代际变化，在强烈的气候变化后，它与太平洋年代际振荡 (PDO) 之间存在明显的负相关性。这一关键转变的标志是 PDO 在 1997 年首次过渡到负相位，这是自 1979 年以来的一个显着变化，导致 EA 地区与 TC 相关的极端降雨量显着增加。与此同时，西太平洋西北地区海面温度（SST）上升加剧了西太平洋副热带高压（WPSH）环流。与副高相关的东偏流随后加强，导致热带气旋轨迹向大陆迁移，从而加剧了与热带气旋相关的极端降水。