Precipitation Variability and Extreme Events in Eastern China during the Past 1500 Years

Abstract

A proxy precipitation index dataset for the period 501 - 2000 over eastern China (east of 105°E; 25 - 40°N approximately) was statistically derived from three existing datasets, which were reconstructed based on Chinese historical documents and instrument measurements. The index was then used to analyze decadal-to-centennial precipitation variability with a focus on three subregions, North China Plain (34 - 40°N approximately), Jiang-Huai area (31 - 34°N approximately) and Jiang-Nan area (25 - 31°N approximately). In addition, major drought/flood events considering severity, persistency, and spatial coverage were also identified. On the centennial time scales, precipitation variation in eastern China exhibited four dry epochs (500s - 870s, 1000s - 1230s, 1430s - 1530s and 1920s - 1990s) and three wet epochs (880s -990s, 1240s - 1420s and 1540s - 1910s), with multi-decadal dry/wet fluctuations within each epoch. However, variation showed strong regional differences, for example, opposite trends were found in the Jiang-Nan area and Jiang-Huai area during the 11 - 13th centuries and in the North China Plain and Jiang-Nan area since the 16th century. The data also showed 16 drought and 18 flood events in eastern China, with the most severe drought event occurring in 1634 - 1644. Droughts dominated in the 12 - 14th centuries, but since the middle of the17th century eastern China has been more subject to flooding. The severity of floods during the 20th century was comparable in intensity to historical times, but the droughts were usually less severe.