Reconstruction of Typhoon Frequency and Social Impact in Honshu Island, Japan since AD1600

Abstract

In this research regarding typhoons in Honshu, documentary records in AD1600-1883, early instrumental records in AD1884-1939, and meteorological records since AD1939 are used to determine typhoons through such exclusive terms as "Ame-Kaze" (heavy rain and wind), "Arashi" (storm or typhoon), "Fu-Su Damage" (the flood disaster or typhoon), and "Dai-Fu" (typhoon) and such expressions of "wind, rain and tide". A typhoon is determined by the criteria that the latitude distance is less than 2.4 and the movement speed is 24.8 km/h - 41.7 km/h. The typhoon frequency series for Honshu Island during AD1600-2020 was formed by linking data about typhoons in documentary records with data about "significant" typhoons in instrumental records. The frequency sequence suggests that the typhoon frequency in Honshu hits the highest record in the past 20 years since the 17 th century. On the inter-decadal scale, global/hemispheric warming has coincided with the increasingly frequent typhoons in this century, but in the long term, the former shows a phased positive correlation with the typhoon frequency, with rapid warming in the Northern Hemisphere occurring at the same pace as frequent typhoon activity, a phenomenon that has only been more clearly demonstrated since the turn of the century. The El Nino-Southern Oscillation (ENSO) phenomenon, to some extent, has an antiphase relationship with the typhoon frequency in Honshu on the inter-decadal scale. As ENSO intensifies, the typhoon frequency in Honshu decreases. However, La Nina is not related to the increasingly frequent typhoons in this region. From the 1820s to the 1840s, Honshu saw a marked increase in typhoon frequency, which led to frequent "flood disasters or typhoons", exacerbating social unrest in Japan at that time. In the "Tenpō Reform" (AD1841-1843), the last reform chance for Tokugawa Shogunate, the Shogun chose AD1841 with rare typhoons to launch political reform. However, it ultimately failed as typhoons came back to Honshu in AD1843. This failure accelerated the downfall and breakdown of the Shogunate.