Frequency of Synoptic-Scale Precipitation Events Recorded by Daily Resolved δ18O of Land Snail Shells

Land snails exhibit the potential for capturing synoptic-scale precipitation events through the δ¹⁸O records of their shells (δ¹⁸O_shell), but the application is hindered by the absence of a practical methodology for tracking these events. Here, we developed a statistical methodology to track the synoptic-scale precipitation events from daily resolved snail body fluid δ¹⁸O (δ¹⁸O_BF) record. We further tested and verified our approach using daily resolved δ¹⁸O_shell records of modern Cathaica fasciola from the Chinese Loess Plateau (CLP). The reconstructed 3-day-timescale precipitation events frequencies using first derivations of δ¹⁸O_BF and δ¹⁸O_shell shows strong agreement with instrumental data (>85% detection accuracy). The strong correlation between precipitation days in snail-growing-season and annual precipitation amounts across the CLP also permits the reconstruction of synoptical precipitation frequency for investigating the interannual variability of precipitation. Our study paves the avenue in paleoweather study, enabling quantitative reconstructions of past synoptic-scale precipitation events.