Variation of Tropical Cyclone Track in the Western North Pacific during ENSO Developing and Decaying Years

This paper aims to further explore the influence of various ENSO (El Niño-Southern Oscillation) phases on the tropical cyclone (TC) track over the western North Pacific (WNP). Based on the best-track TC data for the period 1979-2015 from the Shanghai Typhoon Institute (STI) of China Meteorological Administration (CMA), the present study applies the Finite Mixed Model algorithm to cluster the TC tracks. TC tracks from the best-track 1979-2015 dataset are classified into seven distinct clusters, i.e., Cluster-1 (WNP westward cluster), Cluster-2 (South China Sea westward cluster), Cluster-3 (coastal recurving cluster), Cluster-4 (low latitude recurving cluster), Cluster-5 (ocean recurving cluster), Cluster-6 (offshore recurving cluster) and Cluster-7 (Japan Sea recurving cluster). Besides, the four phases (El Niño developing years, El Niño decaying, La Niña developing years and La Niña decaying year) of ENSO are determined by S-EOF (Seasonal-Empirical Orthogonal Function) method. After that, the study analyzes the impacts of different ENSO phases on TC activities and circulation situations. The results show that Cluster-6 is the main path in El Niño developing years and TCs are active in the southeastern quadrant of the WNP. Cluster-2 and Cluster-7 are the two major tracks in El Niño decaying years. In La Niña developing years, TCs are active over the western part of the WNP and Cluster-7 accounts for most of the TC tracks. In La Niña decaying years, TCs are active over the southwestern quadrant of the WNP and Cluster-3 is the major TC path.