中国近530年干湿变化及其持续性特征研究.docVIP

中国近530年干湿变化及特征龚志强封国林1. 兰州大学大气科学学院，兰州 730000 2. 国家气候中心，中国气象局气候研究开放实验室，北京 100081 3. 中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京 100029 qgzq0929@126.com 2007-08-06收稿,2008-01-07改回. 中图法分类号 P467 Dry-Wet Changes and its Durative Characteristics during the Past 530 Years GONG Zhiqiang1, 2 ZHI Rong1 FENG Guolin2, 3 ZHANG Qiang2 1. Atmospheric Science College, Lanzhou University, Lanzhou 730000, China 2. Laboratory for Climate Studies, National Climate Research Center CMA, Beijing 100081, China 3. Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, CAS, Beijing 100029, China  Abstract Based on a dry-wet (DW) index series of last 531 years at 48 stations, we divided the study area into three regions: Area Ⅰ covers North China and the east of Northwest China; Area Ⅱ covers most of the Yangtze River basin; Area Ⅲ covers South China and the Southeast coastal region. The evolutional characteristics of the mean value segments of the DW index series for each area were studied using the power spectrum analysis, the filtering method, and the BernaolaGalvan algorithm. The results show that the frequency of DW transition in the drought-intensive period of the last 130 years, has increased in Area Ⅰ, not obviously changed in Area Ⅱ, but decreased in Area Ⅲ, in comparison with the other two earlier historical droughtintensive periods. In the drynesswetness transition periods, abrupt change points were relatively concentrated, i.e., the climate was unstable, and various climatic extreme events were likely to occur. Based on the period analysis results of the DW index, we found that the current dry epoch started at about 1920 in Area Ⅰ with severe droughts recorded from the late 1970s to the early 1980s, might last for about 50-70 years in this century, and then a DW shift will take place; while the current wet epoch in Area Ⅱ may also continue in the next several decades. Comparing DW variations of Area Ⅰ, Ⅱ, and Ⅲ with the Northern Hemisph