1750年来西南季风区降水年代际变化及与东部的对比研究

本研究拟以西南地区（包括四川、贵州、云南3省和重庆市）清代雨雪分寸记录为基础资料；通过在土壤质地和降水类型均具有代表性的11个农业气象站点开展自然降水的田间入渗深度观测实验，构建雨季（5-10月）期间各站降雨日数、入渗深度与降雨量的定量关系，重建15个站点1750年来分辨率为年的雨季降水量变化序列，辨识西南季风区雨季降水的年代际变化特征、极端旱涝事件的长期变化趋势及其可能原因；并通过其与已重建的东部地区季风雨季降水序列的对比，探究西南季风区与东部季风区降水长期变化特征的异同；为深入理解亚洲季风系统及其不同分支的长期变化规律与相互关系提供降水长序列数据和区域案例。

This project will aim to reconstruct a set of annual precipitation data during the rainy season (May-October) since AD1750, in the selected 15 sites, covering the monsoon region of southwest China (including Sichuan, Guizhou, Yunnan provinces and Chongqing), the Yu (rainfall)-Xue (snowfall)-Fen (0.32cm)-Cun (10-fen) archives in the Qing Dynasty will be used as the precipitation proxy evidences, and the empirical relationship between depth of moisture penetration and rainfall amount will be obtained based on the field infiltration measurement at 11 agricultural meteorological stations, which have high representiveness for different soil textures and precipitation types. And the experimental method will follow the measurement documented in the historical records of the Qing dynasty. The inter-decadal precipitation variability, and the long-term trend and possible causes of extreme drought/flood events will be recognized. The precipitation difference between southwest and southeast monsoon regions will be analyzed by comparing with the precipitation series in the eastern monsoon region, and the possible links between precipitation and oscillation indices of ocean and atmosphere (such as NAO, ENSO, PDO and IMO) or external forcings will be detected. Our research will contribute data set and regional study cases to understanding long-term variations of Asian monsoon and relationship between their sub-moonsoon systems.