Ages of major Little Ice Age glacier fluctuations on the southeast Tibetan Plateau derived from tree-ring-based moraine dating
Ages of major Little Ice Age glacier fluctuations on the southeast Tibetan Plateau derived from tree-ring-based moraine dating
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DOI：
10.1016/j.palaeo.2015.01.002
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发表时间：
2015-03
期刊：
影响因子：
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通讯作者：
P. Hochreuther;D. Loibl;Jakob Wernicke;Haifeng Zhu;Jussi Grießinger;A. Bräuning
中科院分区：
文献类型：
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作者：
P. Hochreuther;D. Loibl;Jakob Wernicke;Haifeng Zhu;Jussi Grießinger;A. Bräuning
青藏高原冰川进退被广泛认为是气候变化的指示器，对亚洲夏季风等宏观气候强迫机制非常敏感。然而，人们往往不清楚为什么有些冰川比其他冰川退缩或前进得更早，特别是关于所谓的“小冰期（LIA）最大期”的时间。在这项研究中，我们提出了新获得的树木年轮数据，从四个冰川前场在念青唐古拉山脉东南TP和链接到以前的研究。两个冰川形成了一个双舌冰碛设置在LIA期间，树木提供了两个不同的主要冰川范围的最低年龄。结合来自第三个冰川的证据，可以推断出世纪上半叶、17世纪中期和18世纪期间，普遍寒冷的LIA内有三个温暖的阶段。这意味着之前发生了三次大的寒流。1790年至1850年的一个小的冷相标志着东南TP的LIA的结束。念青唐古拉山脉所有采样的季风性温带河谷冰川，从最后一次大的LIA冰川推进开始退缩的最小年龄仅相差40年。这意味着一个共同的强迫，其对冰川动力学的影响只是轻微改变地形因素或当地的气候条件。回归分析表明，冰川从最大程度退缩的延迟主要与冰川规模有关，消融面积方面的影响较小。所有的冰碛年龄突出中间LIA暖相对应的暖相在北方半球的东南TP，从而证明季风温带冰川是高度敏感的档案北方半球的气候条件。
Advances and retreats of glaciers on the Tibetan Plateau (TP) are widely regarded as indicators for climate changes sensitive to macroclimatic forcing mechanisms like the Asian summer monsoon. However, it often remains unclear why some glaciers retreat or advance earlier than others, particularly regarding the timing of the so-called ‘Little Ice Age (LIA) maximum’. Within this study, we present newly acquired tree-ring data from four glacier forefields in the Nyainqêntanglha Range on the southeastern TP and link them to previous studies. Two of the glaciers formed a double-tongue moraine set during the LIA, with trees providing minimum ages for two different major glacier extents. In combination with evidence from a third glacier, three warm phases within the generally cold LIA can be deduced during the first half of the 16th century, and the mid-17th and 18th centuries. This implies the occurrence of three preceding major cold spells. A minor cool phase between 1790 and 1850 marks the end of the LIA on the southeast TP. Minimum ages for beginning retreat from the last major LIA glacial advance differ by only 40 years for all sampled monsoonal temperate valley glaciers in the Nyainqêntanglha Range. This implies a common forcing, whose impact on glacier dynamics is only slightly altered by topographical factors or local climatic conditions. Regression analysis suggests that the delay of the glacier retreat from the maximum extent is mainly related to glacier size, with minor influence of ablation area aspect. All moraine ages highlight intermediate LIA warm phases on the southeast TP corresponding to warm phases on the northern Hemisphere and thus prove monsoonal temperate glaciers to be highly sensitive archives for northern hemispheric climatic conditions.