How Typhoon/Mountain Interaction Influences Precipitation Distribution

About this animation

COMET animations communicate scientific concepts visually. The ones below were designed to help learners see how the relationship between Taiwan's Central Mountain Range and a typhoon’s circulation, structure, and intensity influence precipitation distributions across the island. They are included in the MetEd lesson Typhoon QPF in Taiwan, which introduces the typhoon QPF forecasting methodology used by Taiwan's Central Weather Bureau.

Morakot (2009) Content

Soulik (2013) Content

Tembin (2012) Content

Taiwan is a subtropical island (400 km long and 150 km wide) with a steep, north-south orientated mountain range called the Central Mountain Range (CMR). The CMR rises above 3,000 m over a distance of 50 km. Consequently, the elevated terrain has an influence on the typhoon-related torrential rainfalls, which can cause great devastation in the form of flooding, landslides, and debris flows.

The interaction between the CMR and a typhoon’s circulation, structure, and intensity presents a major challenge to producing accurate quantitative precipitation forecasts (QPFs). A typhoon's rainfall pattern is usually phase-locked with the elevated terrain of Taiwan's CMR, an interaction known as the "topographic phase-locked effect". As illustrated in the tabs, certain parts of the island can experience great amounts of precipitation, depending on the typhoon's specific position relative to the CMR and how its moisture interacts with the topography when it is in that position.