Variations in the summer monsoon rainbands across eastern China over the past 300 years

Based on reconstructions of precipitation events from the rain and snowfall archives of the Qing Dynasty (1736--1911), the drought/flood index data mainly derived from Chinese local gazettes from 1736--2000, and the observational data gathered since 1951, the spatial patterns of monsoon rainbands are analyzed at different time scales. Findings indicate that monsoon rainfall in northernChina and the middle-lower reaches of the Yangtze River have significant inter-annual (e.g., 5--7-yr and 2--4-yr) as well as inter-decadal (e.g., 20--30-yr and quasi-10-yr) fluctuation signals. The spatial patterns in these areas also show significant cycles, such as on a 60--80-yr time scale, a reversal phase predominates the entire period from 1736--2000; on a quasi-30-yr time scale, a consistent phasewas prevalent from 1736 to 2000; and on a 20-yr time scale, the summer monsoon rains show differentspatial patterns before and after 1870.