It is generally believed that the Maritime Continent (MC) is rarely affected by tropical cyclones (TCs) due to its equatorial location. However, this study reveals that TCs in the tropical western North Pacific can significantly suppress rainfall over the MC and its surrounding seas, based on the composite analysis. This suppression effect of TCs exists across all phases of the Madden–Julian Oscillation (MJO). TCs greatly alleviate rainfall enhancement during the convective phases of the MJO and aggravate rainfall suppression during the suppressive phases. Particularly, TCs reduce the likelihood of extremely high rainfall in convective MJO phases from 9% to 5% and increase the likelihood of extremely low rainfall in suppressive MJO phases from 10% to 16%. The rainfall suppression is attributed to the lower-tropospheric southwesterly anomalies to the south of TCs, which result in moisture divergence over the MC. Additionally, the upper-tropospheric equatorward outflows of TCs also promote subsidence and suppress rainfall. This study introduces a new factor influencing the rainfall over the MC from a synoptic climatology perspective.

人们普遍认为，由于位于赤道，海洋大陆 （MC） 很少受到热带气旋 （TC） 的影响。然而，基于复合分析，本研究揭示了热带西北太平洋的 TC 可以显着抑制 MC 及其周围海域的降雨。TC 的这种抑制作用存在于 Madden-Julian 振荡 （MJO） 的所有阶段。TCs 大大减轻了 MJO 对流阶段的降雨增强，并加剧了抑制阶段的降雨抑制。特别是，TC 将对流 MJO 阶段出现极高降雨量的可能性从 9% 降低到 5%，并将抑制性 MJO 阶段出现极低降雨量的可能性从 10% 降低到 16%。降雨抑制归因于 TC 以南的对流层低层西南距平，这导致 MC 上的水汽散散。此外，TC 的对流层赤道上部流出也促进了沉降并抑制了降雨。本研究从天气气候学的角度引入了一个影响 MC 降雨量的新因素。