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引用本文:施雅风,贾玉连,于革,杨达源,范云崎,李世杰,王云飞.40-30kaBP青藏高原及邻区高温大降水事件的特征、影响及原因探讨.湖泊科学,2002,14(1):1-11. DOI:10.18307/2002.0101
SHI Yafeng,JIA Yulian,YU Ge,YANG Dayuan,FAN Yunqi,LI Shijie,WANG Yunfei.Features, Impacts and Causes of the High Temperature and Large Precipitation Eventin the Tibetan Plateau and Its Adjacent Area During 40-30kaBP. J. Lake Sci.2002,14(1):1-11. DOI:10.18307/2002.0101
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40-30kaBP青藏高原及邻区高温大降水事件的特征、影响及原因探讨
施雅风1,2, 贾玉连2, 于革2, 杨达源3, 范云崎2, 李世杰2, 王云飞2
1.中国科学院寒区旱区环境与工程研究所, 兰州 730000;2.中国科学院南京地理与湖泊研究所, 南京 210008;3.南京大学城市与资源学系, 南京 210093
摘要:
40-30kaBP相当于末次冰期大间冰阶或海洋氧同位素MIS3晚期.青藏高原在岁差周期夏季高太阳辐射作用下,据古里雅冰芯与若干孢粉记录指示温度比现在高 2-4℃,高原及邻区众多大湖的高湖面记录指示大范围降水丰沛.应用Kutzbach水能平衡方程推算了封闭湖泊流域 (青海湖、扎布耶/拉果错、阿克塞钦/甜水海)年平均降水可达 640mm,560mm,260mm,分别是现代降水的 1.7倍,3倍,5倍.高原及邻区包括祁连山以北和云南部分区域在内的大降水对水系河流产生了重大影响.高原内部河湖串联,水系合并;如色林错、班戈错、纳木错串联为高原上最大的内陆水系;若尔盖古湖外流并入黄河水系;长江上游大水在三峡束狭形成强烈旋涡掏蚀成低于海平面的深槽,形成了深槽中、底部的砂砾沉积.这次高温大降水事件是由高太阳辐射导致的由青藏高原高温热低压加强、热带洋面增暖蒸发强烈、南半球越赤道气流增强共同作用而形成的高原特强夏季风,同时极地冰盖迫使西风带南移也可能加强了对高原尤其是西部的降水.H3事件(27kaBP)促进了高温大降水事件的结束,H4事件 (35.5kaBP)则可能短期萎缩了夏季风,使高温大降水事件呈现不稳定性特点.
关键词:  青藏高原  高湖面记录  高温大降水  水能平衡公式
DOI:10.18307/2002.0101
分类号:
基金项目:国家重点基础研究发展规划项目(G1998040800)
Features, Impacts and Causes of the High Temperature and Large Precipitation Eventin the Tibetan Plateau and Its Adjacent Area During 40-30kaBP
SHI Yafeng1,2, JIA Yulian2, YU Ge2, YANG Dayuan3, FAN Yunqi2, LI Shijie2, WANG Yunfei2
1.Lanzhou Institute of Glaciology and Geocryology, Chinese Academy of Sciences, Lanzhou 730000, P.R.China;2.Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P.R.China;3.City and Resource Department, Nanjing University, Nanjing 210093, P.R.China
Abstract:
Based on records of the Guliya Ice Core (35.6°N,80.5°E) pollen and high lake levels in the Tibetan Plateau and its adjacent area, there appeared a particular warm and wet stage with the mean temperature 2-4℃ higher and large precipitation much more than that of the present.The reconstructed precipitations with Kutzbach's water and energy balance model of closed lake basin are estimated up to 640mm,560mm and 260mm in the Qinghai Lake,Chabyer Caka/Laguo Co, and Akesaiyi/Tianshuihai Lake which are 1.7,3,5 times of thatin the present respectively.The large precipitation extended to the north slope of Qilian Mountains at the north and to Yunnan Province at the south-east of Qinghai-Xizang plateau had played an important role in the geomorphological evolution of some liveis originated from the Tibetan Plateau.The upstream river pattern of the Yellow River same as present, had come into being for the Zoige Palaeolake overflowing to meet the headward erosion of the Yellow River in the borderland of Gansu and Sichuan Provinces.The formation of the deep channels with their bottom lower than present sealevel in the Three Gorge area in the middle reach of the Yangtze River might be related to high speed flood resulted from the upstream large precipitation in the Tibetan Plateau.While flood currents were narrowish and hindered in the gorge channel the high energy turbulent flow carried large quantitative gravels to cut the river bottom and formed the deep channels (formed before 40kaBP).Some 14C dates of the buried woods between 40-30kaBP, in the gravel deposits at the channel bottom indicated the upper mechanism process.Some separated closed lake catchments in the Tibetan Plateau, such as,Serling Co,Nam Co and Pangkog Co were merged into a great closed catchment by water overflow.This high lake leveleventis mainly caused by the particularly strong Indian monsoon for enhanced cross equator aircurrent from south hemiphere over Indian Ocean activated by high solar radiation of precession cycle in low latitude.On the other hand we infer in the period between the event H4 (35.5kaBP) and H3 (28-27kaBP) the southward-shifted westerlies,from the warm North Atlantic Ocean for northern Eurasia ice sheet gave passive impact on high lake levels for arousing much precipitation.
Key words:  Tibetan Plateau  high level records  high temperature and large precipitation  water and energy balance model
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