Reconstruction of typhoons in the Yangtze River Delta during 1644-1949AD based on historical chorographies

Abstract

The proxy records on typhoons in the Yangtze River Delta from 1644 to 1949AD were extracted from historical chorographies in the Qing Dynasty and the Republic of China Period. In reference to the basic principles for identifying historical typhoons, time series on the Yangtze River Delta over a period of 306 years were developed. The conclusions are as follows. (1) There were a total of 241 typhoons from 1644 to 1949AD. Using the historical chorographies from 1884 to 1949AD, the number of typhoons was 65, equal to 87.8% recorded by meteorological observation. The number of years with differences in typhoon activities reconstructed using two ways no more than once is 55, reaching 83.3% in the period from 1884 to 1949AD. This result means the series of historical typhoons reconstructed using historical chorographies can represent the change of typhoon activities over years. (2) The average number of typhoon activities is 0.79 times per year from 1644 to 1949AD, and they show an increasing trend. These 306 years can be divided into three periods by the average number of typhoon activities: it is low from 1644 to 1784AD, and more typhoon activities are found from 1785 to 1904AD. It is worth noting that the number of typhoon activities reaches the summit in the last period, which is 1.2 times per year from 1905 to 1949AD. (3) Before the 20th century, the number of typhoon activities in warm periods is less than the number of cold periods. However, the number of typhoon activities increased dramatically in the early 20th century. Comparing the typhoon activities with El Nino events, the data show that the number of typhoon activities did not increase when El Nino occurred.