【摘要】 使用树轮年代学的研究方法,对采自青藏高原怒江上游河谷川西云杉进行研究,建立了1761-2016年的树轮宽度年表。通过对树轮差值年表与1960-2016年间的气候数据进行相关普查,发现树轮差值年表与区域上一年8月到当年6月的月降水量相关性最强,相关系数达0. 655。利用该年表重建了研究区过去171年(1846-2016年)上一年8月到当年6月的月降水量变化,经相关检验,降水重建具有较好的可信性。经分析,重建序列中存在3个极端干旱年和4个极端湿润年;研究区经历了5次湿润期和5个干旱期,其中最长湿润期间为1890-1913年,最长干旱期间为1914-1948年;该降水重建序列存在1. 9～2. 0年、2. 3年、2. 5～2. 6年、2. 7～2. 8年的准周期变化;空间相关分析表明该重建序列能够表征研究区大范围的降水量变化;另外,流域水文变化和树木生长变化存在联系,说明怒江上游河谷川西云杉径向生长不仅仅包含了降水信号,而且同时包含了水文信号。更多还原

【Abstract】 Based on the tree-ring research methods,the cores of Picea likiangensis were collected from the upper reaches of Nu River in Tibetan Plateau.We developed a tree-ring width chronology for the period CE 1761– 2016.Growth – climate response analyses showed that the tree-ring width of Picea likiangensis were mainly influenced by total August-June precipitation variation.We then developed a total August-June precipitation reconstruction for the period CE 1846 – 2016.The climate/tree-growth model accounted for 42.9% of the instrumental precipitation variance during the period 1960 – 2016.The leave-one-out cross-validation test showed that the reconstruction model was reliable.3 extreme dry years and 4 extreme wet years were found in the reconstruction sequence.Wet periods occurred during 1856-1871,1890-1913,1949-1956,1986-2008 and 2012-2016; while the periods of 1846-1855,1872-1889,1914-1948,1957-1985 and 2009-2011 were relatively dry.Spatial climate correlation analyses with gridded land surface data revealed that our precipitation reconstruction contains a strong regional precipitation signal for the upper reaches of the Nu River.The interannual cycles( 1.9 ~ 2.0 year,2.3 year,2.5 ~ 2.6 year,2.7 ~ 2.8 year) were found in the precipitation reconstruction.The relationship between streamflow and tree-ring width chronology indicated that the radial growth of Picea likiangensis in the upper reaches of the Nujiang river not only can represent precipitation variation,and but also can reveal hydrological signals.更多还原