Typhoon Bawei Nears: Zheng Ming-dian Reveals 'Cloud Line' West of Taiwan

As Typhoon Bawei nears Taiwan, former Central Weather Bureau Director Zheng Ming-dian has highlighted a distinct cloud band appearing west of the island on satellite imagery. Zheng shared the observation on his Facebook page, noting that the cloud line extends roughly from the coast of Taoyuan.

Zheng explained this phenomenon using principles of fluid dynamics, describing it as a 'separated flow.' He noted that Taiwan, in this context, acts as an obstacle. The cloud band effectively delineates an area where wind speeds are faster to its west and relatively slower to its east. This difference in wind speed on either side of the boundary creates the visible cloud formation.

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This cloud line roughly extends from the Taoyuan coast and forms a boundary with the wind field near Taiwan, making the wind speed west of the cloud line faster and the wind speed east of it relatively weaker.

According to Zheng, Taiwan's position at the 'very end' of this flow places it in a 'free flow' region characterized by higher wind speeds. Conversely, areas on the inner side fall into a 'wake region' with comparatively slower wind speeds. This meteorological observation provides insight into the complex wind patterns influenced by the approaching typhoon and Taiwan's geographical position.

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This is a 'separated flow' phenomenon in fluid dynamics, which can occur when fluid flows past an obstacle.