Previous studies have examined the strengthening of the western North Pacific anticyclone (WNPAC) after the mature phase of El Niño from a large-scale perspective. This study demonstrates that the intensification of WNPAC is preceded by a reduction in western North Pacific tropical cyclones (WNPTCs) approximately 2 months earlier. By estimating the relative vorticity associated with WNPTCs, we find that reduced WNPTC activity accounts for about 33% of WNPAC variability from November of the El Niño year to September of the following year. This reduction is primarily driven by decreased relative humidity at 600 hPa, with low-level vorticity changes playing a minor role. Our finding of the significant impact of WNPTCs on the WNPAC aligns with the circulation theorem and enhances the dynamical understanding of WNPAC changes induced by El Niño.
 

西北太平洋反气旋；热带气旋；厄尔尼诺；