利用钻孔温度梯度重建过去气候变化进展

地球表面的温度信号向地下传播并影响地下温度剖面,这种温度剖面可从钻孔中测量,通过分析可重建过去表面温度变化.虽然认识到表面温度变化对地下温度和热流的影响已有很长时间,但仅在20世纪80年代以后钻孔温度剖面才被广泛应用于气候变化研究.钻孔气候方法与其他重建过去气候的近似方法不同,因为它是基于温度剖面测量与过去气候,即地表温度(GST)、重构参数的直接物理联系之上的.钻孔温度气候研究方法已被证实可以重建过去地表温度趋势,并且最终可结合表面气温序列估计其预观测平均值(POMs).钻孔温度剖面并不是地表温度的代用指标,而是地球大陆表面能量平衡的直接测量.这种地下的信号通过热扩散衰减非常快,因而对从地下温度测量数据中提取过去气候变化信息的方法施加了一个物理限制.描述由钻孔中测量的温度—深度剖面来重建GST历史的基本特征及问题.

Reconstruction of Past Climate Change by Borehole Temperature Gradients: A Review

The signal of Earth’s surface temperature change can penetrate into the ground and influence the ground temperature profiles，superimposed to the long-term steady-state geothermal profile. In turn，the ground temperature perturbation due to the surface temperature change can be used to reconstruct past surface temperature variation. Although the influence of surface temperature changes to underground temperature and heat flow have been recognized for a long time，using the borehole temperature profiles to reconstruct past temperatre changes mainly started in the 1980s. Borehole climate method is different with other approximate methods of reconstructing the past climate since it is based directly on the physical contact of temperature profile，the past Ground Surface Temperature (GST)，and reconstruction parameters. It has been confirmed that using borehole temperature to reconstruct the past surface temperature trend is quite successful，and surface temperature can be eventually combined with the estimated average pre observation (POMs). Borehole temperature logs are not the proxies of surface temperature，but the direct measurement of Earth’s surface energy balance. We synthesize the state-of-the-art knowledge of utilizing borehole temperature profile to infer past GST history and some existing issues associated with this method.