Climatological features of surface winds blowing through the Taiwan Strait

摘要

This study investigates surface winds blowing through the Taiwan Strait using scatterometer wind measurements and atmospheric reanalysis data to present climatological features specific to northeasterly and southwesterly along-strait winds. For both the northeasterly and southwesterly along-strait winds, strong winds occur within the strait and originate from the southern tip of Taiwan Island. Between these strong wind regions, weak winds are formed in the lee of Taiwan Island. This contrastive wind structure extends downwind. While fluctuating winds are aligned with the strait throughout the year, the northeasterly and southwesterly along-strait winds exhibit contrastive seasonal variations. The northeasterly along-strait winds predominantly occur in the cool season and are induced by the East Asian winter monsoon when the developed Siberian high with cold air moves southward to cover the Asian continent and a cyclone develops to the southeast of Japan. The monthly mean speeds of the northeasterly along-strait winds rapidly increase, coincident with the onset of the winter monsoon, and gradually weaken with seasonal advance. The southwesterly along-strait winds often occur in the warm season. Although the speeds reach a maximum in the warm season, they are less than the seasonal minimum speeds for the northeasterly along-strait winds. In the warm season, tropical cyclones approaching Taiwan Island from the southeast create a large pressure gradient across the strait and induce the strong northeasterly along-strait winds. The southwesterly along-strait winds blow along the western periphery of the Pacific high developing westward. Tropical cyclones after making landfall on the Asian continent also contribute to the southwesterly along-strait winds.