Cluster analysis of tropical cyclones affecting the Taiwan Strait

Automatic weather station (AWS) observations are used to select tropical cyclones (TCs) affecting the Taiwan Strait during 2007-2016. Applying these data, the influence of TCs on the Taiwan Strait is measured and TCs with weak or no impact are removed. Objective statistical properties of the remaining TCs are analysed by clustering them into three groups using the fuzzy C-means method. Clusters are differentiated as (a) TCs affecting the Taiwan Strait but recurving at the edge of the TC alert area, (b) TCs moving straight across The Philippines and the South China Sea, and (c) TCs striking Taiwan and eastern China and recurving after landfall. Differences among the clusters include in the spatial range and duration of gales monitored by AWS, and the track, intensity, and genesis location of TCs. Also analysed are the influence of large-scale atmospheric environments on TC motion, sea-surface temperature responses to TCs, and the influence of El Nino-Southern Oscillation on TC classifications.