Research groups such as Hokkaido University, Tokyo Metropolitan University, Narumi University, and Kobe University will restore typhoon path data and meteorological data observed at meteorological stations and lighthouses from 10 to 1877. The number, strength, and landing points of typhoons that landed in Japan were clarified.
In recent years, strong typhoons that cause great damage have landed in Japan.It is predicted that typhoons approaching Japan will become stronger due to global warming, but it is still difficult to grasp how typhoons are actually changing in the long run.
Under these circumstances, in this research, typhoon path data from the latter half of the 19th century and meteorological data observed at the meteorological observatory and the lighthouse were collected and restored to data that can be used for comparative analysis with the current meteorological data, and then the maximum wind velocity data was obtained. We have redefined typhoons using pressure and wind data so that the same typhoon definition can be used from pre-1950s to the present day.By this method, we succeeded in restoring the typhoon data that landed in Japan from 10 to 1877 by the same method throughout the period.
As a result of analyzing the restored typhoon data, the number of typhoons landing has tended to be high since 2014 and low in the latter half of the 20th century.There were many other periods, including the 19th century, but there was no long-term increasing trend, and it was found that the period fluctuated every several decades.
The intensity of landing typhoons has been increasing since the 1990s, but there have been no landings in recent years that are as strong as the four major typhoons of the Showa era.Regarding the landing point, the tendency toward the northeast has been remarkable since the 4s, but it was found that it changed in the northeast and southwest directions in a cycle of about 1970 years.
In addition, in this study, it was the first time to restore the route of a typhoon that approached Japan at the end of the Edo period before the observation of the meteorological observatory in Japan, using the meteorological data recorded in the US Navy Perry fleet and the British Navy's logbook. Successful.It can be said that the logbook of a foreign ship that was sailing with a meteorological instrument during the Age of Discovery is effective data for clarifying the climate of the Asian region in the era when there is no meteorological data.
Paper information:[Climatic Change] Tropical cyclones over the western north Pacific since the mid-19th century
