A 100-year reconstruction of typhoon events on the inner shelf of the East China Sea: Coupling of meteorological observations and sedimentary records

Future global changes may increase the intensity and frequency of extreme events, coupled with the rapid rise in sea level, bringing the issue of updated protection standards to the coastal areas. Due to the short length of observational records, it is necessary to find other alternative records to extend typhoon records other than meteorological observations. The sedimentary records and historical documents provide alternative approaches to extend typhoon records. This study attempts to reconstruct typhoon events on a 100-year scale on the inner shelf of the East China Sea through coupling of meteorological observations and sedimentary records. This reconstruction is compared with the meteorological disaster records to explore the preservation potential, path and intensity of typhoon events in the shelf mud area. In May 2018, a 2 m Core J1 was collected in the offshore area of Zhejiang Province. Typhoon events were comprehensively identified by multiple indicators (grain size distribution, D₉₀, Zr/Fe, Sr/Al and Ca). The radioisotope²¹⁰Pb dating method was used to determine the age model of Core J1. The results show that the sedimentation rate of Core J1 is about 1.1 cm/a, and the time span is about 1836 to 2018. 25 typhoon events are identified in Core J1 and 10 of which match the meteorological observation period (1950−2018). The average wind speed of the 10 typhoons is close to the one of all typhoons affecting Core J1, and most of them belong to the strong typhoons of type III and IV landing on Zhejiang Province and Fujian Province. Through multivariate comprehensive analysis, it is found that the preservation potential of typhoon events in sedimentary records is close to 30% for Core J1. In addition, the typhoon events recorded in historical documents may be biased towards stronger landing typhoons, thus the number of typhoons recorded in literatures is significantly less than that actually affected. The knowledge obtained here helps to not only make better use of sedimentary records to expand the time span of typhoon records, but also guide future sampling to obtain more complete typhoon sedimentary records.