Tropical cyclone landfall in Japan during 1900-2014

Tropical cyclone best track dataset is available from late 1940s over the western north Pacific by Joint typhoon warning center, RSMC Tokyo, Shanghai Typhoon Institute and Hong Kong Observatory. However before late 1940s, tropical cyclone dataset were not used due to the difference of tropical cyclone definition. We have collected historical tropical cyclone track data from various bulletins stored in US, Japan, Philippines, China and other countries back to late 19th century through the “data rescue” activity. In this study we reanalyzed the tropical cyclone numbers landed in mainland Japan using historical tropical cyclone track data and station data from 1900. Tropical cyclone is defined when it was generated south of Japan and measured less than 1000hPa near the cyclone. Landfall is defined when the minimum sea level pressure measured less than 1000 hPa near the landfall point and the right/left side station measured clockwise/anticlockwise wind direction change during the passage in Japan.

About 3.05 tropical cyclones per year were landed in Japan during 1900-2014. The maximum landfall number was 10 in 1951 and minimum was 0 in 1973, 1984, 2000 and 2008. The difference of landfall numbers from RSMC Tokyo using maximum wind speed definition was 0.06 per year during 1951-2014. We cannot find increasing or decreasing trend of landfall numbers during 1900-2014. The minimum sea level pressure was 911.9 hPa observed during the landfall in Muroto in September 21, 1934. Very strong tropical cyclone landfall of less than 940 hPa was concentrated from 1930s to 1960s. On the other hand, the ratio of strong tropical cyclone landfall numbers less than 970 hPa tends to increase from 1990s and reached more than half of tropical cyclone landfall in 2000s. Another large numbers of strong tropical cyclone landfall ratio were observed in 1900s and 1930s which indicates interdecadal variability of strong tropical cyclone landfall ratio during the 20th century.