【摘要】 利用在青海柴达木盆地建立的祁连圆柏树轮宽度指数年表,分析了自公元前800年以来树轮所记录的该地区2800年来极端干旱事件的变化。研究发现,过去2800年来极端干旱事件的出现存在群发性和间歇性的特点,其中魏晋南北朝时期(公元3世纪至4世纪)和明清时期(15世纪中叶至19世纪)是极端干旱事件的群发期,公元5世纪至12世纪的800年内极端干旱事件的出现频率较低。出现在西汉末年、东汉初年前后的持续性干旱是柴达木盆地过去2800年内最严重的极端干旱事件。更多还原

【Abstract】 Droughts are one kind of the most devastating natural hazards faced by China,severe droughts have had large impacts on economies,society,and environment of China,especially in the arid and semi-arid regions of northwestern China. The instrumental record of this region is not more than 100 years and it contains only a limited subset of severe drought cases,so it is necessary to turn to the paleoclimatic record to examine the full range of past drought variability to gain the improved understanding of sustained severe extreme drought events. In this study,the authors analyzed the severe extreme drought events of the past 2800 years inferred from tree-ring width variations in Qaidam Basin,Qinghai. It is found that the extreme drought events occurred in a cluster in some periods and intermittten in other periods. In the Wei,Jin,and Southern/Northern Dynasties period ( 3rd century to 4th century AD) and in the Ming and Qing Dynasties period ( mid-15th century to 19th century AD),severe extreme drought events occurred in high frequency,while in the period from the 5th century to 12th century occurred less frequently. The most serious extreme drought over the past 2800 years occurred in the transition of Western Han to Eastern Han Dynasties.更多还原