[A-AS02] 台風研究の新展開～過去・現在・未来

[AAS02-P11] Cluster Analysis of Typhoon Tracks by using SOM

*加藤 雅也¹、荒木 孝夫²、坪木 和久¹ (1.名古屋大学宇宙地球環境研究所、2.東京海上研究所)

キーワード：台風、クラスター解析、SOM、気候変化、d4PDF

It is very important to understand the changes in typhoon intensity and its tracks associated with climate change, especially when considering disasters and associated damage. We have developed a method for cluster analysis of typhoon tracks using Self-Organizing Map (SOM) based on the characteristics of typhoons at each time (location, central pressure, maximum surface wind speed, etc.). One of the important features of this method is that it could handle different numbers of time series of data (which means different lifetimes of typhoon), which is difficult with ordinary time series SOM.This makes it possible to cluster typhoons by taking into account not only their tracks but also their lifetimes. The method was applied to all typhoons in all climates calculated in dataset of database for Policy Decision making for Future climate change (d4PDF) (13,471 in the latter half of 20th climate (HPB), 7,566 in the climate 2K warmer than the pre-industrial climate (HFB2K), 11,541 in the 4K warmer climate (HFB4K), and 16,452 in non-warming climate (NAT)). In HFB4K, clusters of typhoons identified in the western North Pacific that are short-lived and move both westward and northward tended to increase the existence ratio. Clusters of typhoons identified the central North Pacific had the smaller existence ratio in all climates compared to them identified in the western North Pacific. In HFB4K, the existence ratio of clusters with westward-moving typhoons decreased. On the other hand, the existence ratio of clusters with northward-moving typhoons over the sea east of Japan increased.