In situ measurements of firn compaction profiles using borehole optical stratigraphy
In situ measurements of firn compaction profiles using borehole optical stratigraphy
复制标题
使用钻孔光学地层学对岩石压实剖面进行原位测量
DOI：
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发表时间：
2011
影响因子：
3.4
通讯作者：
E. Waddington
中科院分区：
文献类型：
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作者：
R. Hawley;E. Waddington
摘要我们开发了一种技术，在该技术中，我们使用钻孔摄像机和后处理软件来记录光学亮度作为极地积雪深度的函数。我们称这种方法为井眼光学地层学。为了测量积雪压实，我们注意到由初始“基线”日志检测到的钻孔壁上的光学特征的位置。我们在随后的日志中跟踪这些功能的位移。结果提供了一个测量的相对垂直运动，从而压实的积雪在调查期间。我们已经成功地使用这个系统在格陵兰岛的首脑会议上，测量的深度分布的积雪柱缩短经历了三个1年的时间内在钻孔。在首脑会议的积雪的最高30米是压实的一个简单的稳态模型预测，这意味着在首脑会议的积雪密度分布是在或接近稳定状态，在过去的2070年。
Abstract We have developed a technique in which we use a borehole video camera and post-processing software to make a record of the optical brightness as a function of depth in polar firn. We call this method borehole optical stratigraphy. To measure firn compaction, we note the positions of optical features on the borehole wall detected by an initial ‘baseline’ log. We track the displacements of these features in subsequent logs. The result provides a measurement of the relative vertical motion and thus compaction of the firn over the survey period. We have successfully used this system at Summit, Greenland, to measure the depth distribution of firn column shortening experienced in a borehole over three 1 year periods. The uppermost 30 m of the firn at Summit is compacting as predicted by a simple steady-state model, implying that the firn density profile at Summit is at or close to steady state over the past ∼70 years.