基于冰川钻孔温度的古气候重建研究进展

Reconstruction of paleoclimate by glacier borehole temperatures:a review

冰川内部温度与过去冰面温度变化密切相关,因此可以利用冰川钻孔温度对过去冰面温度变化过程进行重建。耦合的热传导-冰流物理模型与相关反演算法,是基于冰川钻孔温度进行古气候重建研究的理论基础和关键。论文收集了过去三十多年基于冰川钻孔温度进行古气候重建的研究文献,从冰川钻孔温度对气候变化的响应和古气候重建等方面进行了概述,并简要讨论了不同反演算法的优劣性和适用条件。尽管很多因素(如太阳辐射、融水等)都会对冰川钻孔温度造成影响,但两极或高纬地区的冷冰川钻孔温度能较好地反映气候变化历史。目前已通过这些不同地区的冰川钻孔温度,重建了末次冰期冰盛期以来不同时间尺度的气候变化历史,同时可与对应的冰芯记录相互印证。此外,通过冰川钻孔温度可以研究冰川与气温的耦合作用,并进一步预测冰川对未来气候变化的响应。利用中纬度冷冰川钻孔温度开展古气候重建的研究较少,未来加深这一方面的研究将有助于揭示中纬度高海拔地区的气候变化状况。

Borehole paleothermometry,a reconstruction of the past ground surface temperature change from subsurface temperatures,is an important tool for understanding climate responses to conditions of a certain area in the past. Based on the close relation between glacier inner temperature and surface temperature change,glacier surface temperature variation process can be reconstructed by the borehole temperatures. Because of firnification and ice flow,the climate reconstruction from glacier borehole temperatures is more difficult than for other places such as permafrost. The coupled heat transfers and ice-flow equation and relative inversion algorithm are the theoretical basis and the key method of study on paleoclimate reconstruction by glacier borehole temperatures. In this study,we collected publications about the reconstructions of paleoclimate by glacier borehole temperatures over the last three decades,and reviewed some progresses in these areas. The advantages and disadvantages of different inversion algorithms(trial and error,control methods,Monte Carlo inverse modelling and the Tikhonov regularization method)were briefly introduced and discussed. Although the relationship between borehole temperatures and the climate may be affected by many factors(solar radiation,melt water,and so on),the cold glacier borehole temperatures in polar and high latitude regions can reflect the climate change well. At present the history of climatic changes has been reconstructed on different time scales in the world since the Last Glacial Maximum. Meanwhile,the reconstructed results using glacier borehole temperatures and the climate records in the ice core are able to confirm one another. In addition,by analyzing the glacier borehole temperatures and instrumental records,we can obtain a general understanding of the glacier-climate interactions and predict the response of glacier to climate change. However,less research has been done on the reconstruction of paleoclimate by cold glacier borehole temperatures for the middle latitude regions,and strengthening the study in these areas can help to reveal the climate change at middle latitude with high altitude.