Stalagmite flooding frequency record since the middle Little Ice Age from Central China

Abstract

Comparison of the climate, especially extreme climate changes between the Little Ice Age (LIA) and the present, could provide important information for the predication of extreme climate change in the future. Based on a laminated stalagmite from the middle reaches of the Yangtze River, Central China, an annually resolved stalagmite record of growth rate has been produced dating from 1640 AD. An 11-year running variance sequence of the growth rate shows a positive correlation with a local historical flooding frequency record from 1640 to 1920 AD, suggesting that the stalagmite growth rate variance could be used as a local flooding frequency indicator. In the middle Yangtze catchment, the flooding frequency during the late LIA (1750–1900 AD) is much higher than during the middle LIA (1640–1750 AD) and the early twentieth century (1900–1920 AD). The discrepancy between the stalagmite growth rate variance and the flooding frequency after 1920s AD suggests that the scale of modern flooding is possibly larger than during the earlier periods. Spectral power analysis on growth rate variance of the stalagmite suggests that the flooding cycles around the middle Yangtze River catchment may relate to El Nino/Southern Oscillation (ENSO). The comparison between the stalagmite growth rate variance and reconstructed ENSO records further suggests a link between strong ENSO and high flooding frequency in the middle Yangtze catchment.