The ‘Little Ice Age’ in the Himalaya: A review of glacier advance driven by Northern Hemisphere temperature change
The ‘Little Ice Age’ in the Himalaya: A review of glacier advance driven by Northern Hemisphere temperature change
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DOI：
10.1177/0959683616658530
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发表时间：
2017-02
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影响因子：
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通讯作者：
A. Rowan
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作者：
A. Rowan
北半球在公元1400年至1900年间变冷，导致冰川扩张，这一时期被称为“小冰期”（LIA）。根据冰碛的外观和位置，并且没有数字年龄控制，对喜马拉雅冰川最近进展的早期调查假设这些事件与欧洲确定的LIA进展是同步的。然而，第四纪测年技术的应用，如陆地宇宙形成核素测年，使研究人员能够确定这些年轻冰碛的数值年龄，并澄清冰川高峰发生的时间。本文综述了喜马拉雅山冰川最后一次推进的地质年代学证据。从138个冰川地貌样本中计算出的66个小于2000年（0-2000年）的年龄表明，冰碛高峰的形成发生在1300 - 1600年之间，略早于北半球气温最冷的时期。低气压推进的时间在空间上有所不同，可能受到山脉两侧和沿线地形和气象变化的影响。古气候代用物表明，从公元1300年开始，空气温度变冷，导致亚洲季风向南移动，冬季西风降水增加，在公元1400年至1800年左右的范围内，气候普遍湿润。在气候变化时期，喜马拉雅冰川的最后一次推进是由于北半球寒冷的气温造成的，并且由于低冰期变冷导致大气环流重组，降雪增加而得以维持。
Northern Hemisphere cooling between 1400 and 1900 in the Common Era (CE) resulted in the expansion of glaciers during a period known as the ‘Little Ice Age’ (LIA). Early investigation of recent advances of Himalayan glaciers assumed that these events were synchronous with LIA advances identified in Europe, based on the appearance and position of moraines and without numerical age control. However, applications of Quaternary dating techniques such as terrestrial cosmogenic nuclide dating have allowed researchers to determine numerical ages for these young moraines and clarify when glacial maxima occurred. This paper reviews geochronological evidence for the last advance of glaciers in the Himalaya. The 66 ages younger than 2000 years (0–2000 CE) calculated from 138 samples collected from glacial landforms demonstrate that peak moraine building occurred between 1300 and 1600 CE, slightly earlier than the coldest period of Northern Hemisphere air temperatures. The timing of LIA advances varied spatially, likely influenced by variations in topography and meteorology across and along the mountain range. Palaeoclimate proxies indicate cooling air temperatures from 1300 CE leading to a southward shift in the Asian monsoon, increased Westerly winter precipitation and generally wetter conditions across the range around 1400 and 1800 CE. The last advance of glaciers in the Himalaya during a period of variable climate resulted from cold Northern Hemisphere air temperatures and was sustained by increased snowfall as atmospheric circulation reorganised in response to cooling during the LIA.