Two distinct modes of convection variability over the tropical Indo‐Pacific during January and the associated climate variability over East Asia, especially in Korea, are identified. The first mode (empirical orthogonal functions [EOF1]) exhibits a zonal dipole structure of suppressed convection over the Maritime Continent and enhanced convection over the tropical central Pacific, which represents a typical El Niño response. The second mode (EOF2) is a tripole pattern showing suppressed convection over the eastern Indian Ocean and east of the dateline, and enhanced convection over the tropical western Pacific. The temporal variation of EOF2 exhibits a distinctive positive trend and stronger amplitude after the early 2000s. During the positive phase of EOF2, the sea surface temperature (SST) anomaly pattern displays central Pacific (CP) El Niño, and the associated atmospheric circulation pattern is characterized by a high‐pressure anomaly that directly affects Korea and induces warm and dry conditions. Of the winter months, these distinctive features of EOF2 are particularly evident in January. This study attempts to identify a possible mechanism for the relatively unfamiliar convection structure of EOF2. Enhanced Madden‐Julian Oscillation (MJO) activity over the tropical western Pacific, namely, phases 5, 6, and 7, plays a crucial role in driving the positive phase of the EOF2 convection structure. The recent CP type El Niño, which does not accompany the cold SST anomaly and suppressed convection over the Maritime Continent, may provide favorable conditions for the frequent occurrence of MJO phases 5, 6, and 7.

中文翻译：

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一月东亚/韩国热带对流结构的两种不同模式及相关的气候变化

确定了1月热带印度太平洋太平洋对流变化的两种不同模式，以及东亚（尤其是韩国）的相关气候变化。第一种模式（经验正交函数[EOF1]）显示出一种区域偶极子结构，该区域偶极子结构在海上大陆对流受到抑制，而在热带中部太平洋对流增强，这是典型的厄尔尼诺现象。第二种模式（EOF2）是三重峰模式，显示出印度东部和日期线以东的对流受到抑制，热带西太平洋上的对流增强。在2000年代初期之后，EOF2的时间变化呈现出明显的正趋势，并呈现出更强的振幅。在EOF2的正阶段，海面温度（SST）异常模式显示太平洋中部（CP）厄尔尼诺（ElNiño），相关的大气环流模式的特征是高压异常，直接影响韩国，并诱发温暖干燥的环境。在冬季，EOF2的这些独特功能在1月尤为明显。这项研究试图确定EOF2相对不熟悉的对流结构的可能机制。在热带西太平洋，即第5、6和7期，增强的Madden-Julian振荡（MJO）活动在驱动EOF2对流结构的正相中起着至关重要的作用。最近的CP型ElNiño不伴有冷SST异常并抑制了海上大陆的对流，这可能为频繁发生MJO 5、6和7期提供了有利条件。