| Abstrakt: |
The climate characteristics of remote rainfall events in Taiwan from September to February over 41 years (1980–2020) are studied. These events are induced by the interaction between the northeasterly flow and the typhoon's outer circulation. Our findings reveal that rainfall in northeastern Taiwan becomes more prominent when tropical cyclones move to the remote rainfall‐prone area, located in the north Philippine area to the northern South China Sea, and when the background northeasterly wind speed exceeds 7 m s−1. Under these criteria, the confluence of the typhoon's outer circulation and the northeasterly flow creates a convergence area that enhances rainfall in northeastern Taiwan, increasing the occurrence of moderate to extreme rainfall (ER) events. This leads to an average enhancement in rainfall amount of 80–220 mm per day. Additionally, when typhoons are in the remote rainfall‐prone area, there is a greater than 20% chance for events with maximum rainfall over 200 mm day−1 to occur, particularly in the region of 20°–22°N, 116°−124°E, and north to Luzon Island. In this area, the occurrence rate can exceed more than a 45% chance. The highest risk of ER events occurs between 20°–22°N and 118°−120°E, with a probability of over 90%. Notably, the convergence area for the Taiwan cases does not necessarily coincide with the baroclinic forcing as that associated with remote rainfall events observed in Japan, Korea, and North America. Plain Language Summary: We studied a particular pattern of rainfall in Taiwan that occurs between September and February over a 41‐year period (1980–2020). Our research found that when tropical cyclones (TCs) are far from Taiwan and there is a strong northeasterly wind, it causes more rainfall in northeastern Taiwan. This can lead to moderate to extreme rainfall, with an increase in rainfall of 80–220 mm per day. When tropical storms are in a specific area north of Luzon Island, there is a higher chance of heavy rain, with some places receiving more than 200 mm per day. The highest probability of extreme rain events occurs when TCs are in a specific area between 20°–22°N and 118°−120°E, where the chance of extreme rain in Taiwan is over 90%. It happens because the TC circulation meets with the northeasterly flow and creates a convergence area. It's important to note that the way remote rainfall events happen in Taiwan may not be the same as in Japan, Korea, and North America. Key Points: Northeastern Taiwan experiences heavy rainfall as tropical cyclone (TC) move toward North South China Sea while northeasterly flow >7 m/sTyphoons' outer flow and the northeasterly convergence enhanced remote rainfall events to 80–220 mm/dayAbove 45% of events with max daily rainfall over 200 mm occur when TCs are in the 20°–22°N, 116°–124°E area and north to Luzon Island [ABSTRACT FROM AUTHOR] |
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