Correlation census shows that the correlation between the tree-ring chronologies in the Urumqi River Basin and precipitation during July in the last year to February in the concurrent year is significant,and the best ...Correlation census shows that the correlation between the tree-ring chronologies in the Urumqi River Basin and precipitation during July in the last year to February in the concurrent year is significant,and the best single correlation coefficient is 0.74,with significance level of 0.0001. Using two residual chronologies collected from west Baiyanggou and Boerqingou,precipitation for 348 years can be reconstructed in the North Slope of middle Tianshan Mountains,its explained variance is 62%.According to much verification from independent precipitation data,historical climate records,glacier and other data.it shows that the reconstructed precipitation series of 348 years is reliable.Analysis of precipitation features indicates that there were three wet periods occurring during 1671(?)—1692,1716—1794 and 1825—1866 and three dry periods during 1693 —1715,1795—1824 and 1867—1969.Two wet periods,during 1716—1794 and 1825—1866, correspond to the times of the second and the third glacial terminal moraine formation,which is in front of No.1 glacier in Urumqi River source.According to computation,corresponding annual precipitation amounts are 59mm and 30mm more than now.The reconstructed precipitation series has a significant drying trend from 1716 to 1969.and has better representativeness to the precipitation of Urumqi and Changji Prefecture on the North Slope of Tianshan Mountains.展开更多
全新世气候变化一直是科学界关注的热点问题,尤其是罗布泊地区多次大规模的环境变化导致小河文明和楼兰文明等古文明的消失。笔者等通过对叶尔羌河流域的阿克奇河左岸黄土剖面系统采样和粒度、磁化率及年代学测试,重建了该地区5 ka BP...全新世气候变化一直是科学界关注的热点问题,尤其是罗布泊地区多次大规模的环境变化导致小河文明和楼兰文明等古文明的消失。笔者等通过对叶尔羌河流域的阿克奇河左岸黄土剖面系统采样和粒度、磁化率及年代学测试,重建了该地区5 ka BP以来的古气候环境,并在此基础上分析了昆仑山北区黄土沉积记录的古气候环境与塔里木河下游罗布泊地区小河文明之间的关系。研究结果显示4.5~3.58 ka BP,昆仑山区次生黄土快速堆积,气候较湿润,降水量较多,塔里木河上游水源充足,为下游罗布泊地区提供了大量水资源,也为小河文明的孕育和初期发展奠定了坚实基础;3.58 ka BP以后,昆仑山区的剖面沉积物由次生黄土转为风成黄土,显示气候开始转向干冷,因降水量减少导致流入到罗布泊地区的有效水资源逐步减少,罗布泊生态环境开始恶化,小河文明开始衰退,直至消失。因此小河文明的孕育与昆仑山区全新世湿润期气候有着非常密切的联系。展开更多
使用高空、地面观测资料、地面自动站雨量资料和美国国家环境预报中心(NCEP)再分析资料,通过水汽通量诊断分析、后向轨迹模型等方法,分析了昆仑山北麓和田地区2020年5月5—7日(简称“05·06”过程)和2021年6月14—17日(简称“06...使用高空、地面观测资料、地面自动站雨量资料和美国国家环境预报中心(NCEP)再分析资料,通过水汽通量诊断分析、后向轨迹模型等方法,分析了昆仑山北麓和田地区2020年5月5—7日(简称“05·06”过程)和2021年6月14—17日(简称“06·15”过程)两次极端暴雨过程的环流形势、中尺度系统、水汽输送和收支特征。结果表明:(1)两次暴雨过程有共同的特点:影响系统都为中亚低涡,均有来自里海、咸海一带的水汽输送;对流层低层偏东急流作用显著,最强水汽辐合集中在700~850 h Pa。(2)两次暴雨过程也有明显差异:“05·06”过程的南亚高压为带状分布,水汽输送路径为西方和偏东路径,其中西方路径水汽输送最明显,西边界水汽输入贡献占88%;“06·15”过程的南亚高压为双体型,水汽输送路径为北方和偏南路径,水汽来自阿拉伯海和孟加拉湾的偏南气流向北输送,南方路径输送量远远大于其他路径,南边界水汽输入贡献占78%。(3)和田大气可降水量(PW)增大尤其是超过平均状态时,对强降水出现有指示意义,当PW≥20 mm以上时,可能会出现暴雨或极端暴雨天气。展开更多
基金funded by Xinjiang Science and Technology Commission(980103002)by the National Key Project for Basic Research(G199043501)+1 种基金by the foundation of the open laboratory of National Climate Center,China Meteorological Administrationby the foundation of Observation and Experiment Station of Tianshan Mountain Glacier,Chinese Academy of Seienecs.
文摘Correlation census shows that the correlation between the tree-ring chronologies in the Urumqi River Basin and precipitation during July in the last year to February in the concurrent year is significant,and the best single correlation coefficient is 0.74,with significance level of 0.0001. Using two residual chronologies collected from west Baiyanggou and Boerqingou,precipitation for 348 years can be reconstructed in the North Slope of middle Tianshan Mountains,its explained variance is 62%.According to much verification from independent precipitation data,historical climate records,glacier and other data.it shows that the reconstructed precipitation series of 348 years is reliable.Analysis of precipitation features indicates that there were three wet periods occurring during 1671(?)—1692,1716—1794 and 1825—1866 and three dry periods during 1693 —1715,1795—1824 and 1867—1969.Two wet periods,during 1716—1794 and 1825—1866, correspond to the times of the second and the third glacial terminal moraine formation,which is in front of No.1 glacier in Urumqi River source.According to computation,corresponding annual precipitation amounts are 59mm and 30mm more than now.The reconstructed precipitation series has a significant drying trend from 1716 to 1969.and has better representativeness to the precipitation of Urumqi and Changji Prefecture on the North Slope of Tianshan Mountains.
文摘全新世气候变化一直是科学界关注的热点问题,尤其是罗布泊地区多次大规模的环境变化导致小河文明和楼兰文明等古文明的消失。笔者等通过对叶尔羌河流域的阿克奇河左岸黄土剖面系统采样和粒度、磁化率及年代学测试,重建了该地区5 ka BP以来的古气候环境,并在此基础上分析了昆仑山北区黄土沉积记录的古气候环境与塔里木河下游罗布泊地区小河文明之间的关系。研究结果显示4.5~3.58 ka BP,昆仑山区次生黄土快速堆积,气候较湿润,降水量较多,塔里木河上游水源充足,为下游罗布泊地区提供了大量水资源,也为小河文明的孕育和初期发展奠定了坚实基础;3.58 ka BP以后,昆仑山区的剖面沉积物由次生黄土转为风成黄土,显示气候开始转向干冷,因降水量减少导致流入到罗布泊地区的有效水资源逐步减少,罗布泊生态环境开始恶化,小河文明开始衰退,直至消失。因此小河文明的孕育与昆仑山区全新世湿润期气候有着非常密切的联系。
文摘使用高空、地面观测资料、地面自动站雨量资料和美国国家环境预报中心(NCEP)再分析资料,通过水汽通量诊断分析、后向轨迹模型等方法,分析了昆仑山北麓和田地区2020年5月5—7日(简称“05·06”过程)和2021年6月14—17日(简称“06·15”过程)两次极端暴雨过程的环流形势、中尺度系统、水汽输送和收支特征。结果表明:(1)两次暴雨过程有共同的特点:影响系统都为中亚低涡,均有来自里海、咸海一带的水汽输送;对流层低层偏东急流作用显著,最强水汽辐合集中在700~850 h Pa。(2)两次暴雨过程也有明显差异:“05·06”过程的南亚高压为带状分布,水汽输送路径为西方和偏东路径,其中西方路径水汽输送最明显,西边界水汽输入贡献占88%;“06·15”过程的南亚高压为双体型,水汽输送路径为北方和偏南路径,水汽来自阿拉伯海和孟加拉湾的偏南气流向北输送,南方路径输送量远远大于其他路径,南边界水汽输入贡献占78%。(3)和田大气可降水量(PW)增大尤其是超过平均状态时,对强降水出现有指示意义,当PW≥20 mm以上时,可能会出现暴雨或极端暴雨天气。
