Chen, Jen-PingJen-PingChenTsai, Pei-ChunPei-ChunTsaiChen, Li-RuLi-RuChenWu, Chung-KaiChung-KaiWuFontaine, EmmanuelEmmanuelFontaine2025-12-152025-12-152025-07https://www.scopus.com/pages/publications/105000058266https://scholars.lib.ntu.edu.tw/handle/123456789/734635The profuse winter rainfall over Taiwan's northern coastal mountain area (NCMA) was investigated and quantified, focusing on the associated daily weather types, for ten winters from November 2010 to February 2021. The dominant rainfall-producing system we identified is the boundary-layer-top clouds associated with the northeasterly monsoon (N-type weather), contributing 43 % to the rainfall and 55.6 % to rainy days. Rainfall from the N-type weather correlated highly with the surface winds, total column water (TCW), and the Oceanic Niño Index. While the rainfall depends linearly on TCW, a cubic dependence is found on the northerly wind speed. The N-type rainfall can be drastically enhanced when an overlaying cloud layer emerges in the lower free troposphere. The Oceanic Niño Index represents a large-scale influence on the East Asian winter monsoon, regulating winds and water vapor of the region. Regional-scale composite analysis substantiated such regional influences, with heavier NCMA rainfall associated with stronger Mongolian/Siberian High and enhanced moisture transport at the lower free troposphere over Taiwan. The NCMA winter rainfall shows significant decadal variation, but no apparent long-term trend can be observed from 1940 to 2023.ENSOFrontal systemMarine boundary layer cloudsOrographic effectsWinter heavy rainWinter monsoon[SDGs]SDG13journal article10.1016/j.atmosres.2025.108055