Long-term variation of the typhoon trajectory pattern estimated from the typhoon best track data

The long-term change of the typhoon trajectory pattern has been estimated based on the typhoon best track data for these 50 years. Typhoons are intense tropical cyclones forming in the north-western part of the Pacific Ocean. The long-term changes of the typhoon intensity and occurrence frequency have been examined by many studies. On the other hand, the present study focuses on the the long-term change of the typhoon trajectories. Since the typhoon trajectory pattern may affect the risks of typhoon hazards in a particular region, its long-term change is important in planning actions to reduce the risk of typhoon hazards. We estimated the variation of a typical pattern of typhoon trajectories from the typhoon best track data by using the Gaussian process regression technique. In order to exclude the effect of a seasonal variation, a variation on a longer time scale than an annual variation was considered separately from a seasonal variation. The result indicates north-south shifts of the typhoon trajectory pattern on a 5 year or longer time scale, which is discriminable from the seasonal variation.