Spatial Variability in Firn Properties from Borehole Optical Stratigraphy at the Inland WAIS Core Site

0538639 Waddington该奖项支持一个项目，以研究在2.5公里的20米钻孔阵列的WAIS分水岭冰芯现场附近的积累变化和微观结构特性的模式。 钻孔光学地层学（BOS）是一种新型的光学测量系统，它可以探测由积雪微观结构变化引起的积雪年度尺度层，给出过去40-50年积累空间变化的年度尺度记录。从钻孔光学地层学的数据，最终可以校准对其他数据的微观结构参数的积雪校准BOS的灵敏度密度，孔隙体积和孔隙形状的变化，并通过代理显示这些参数如何在整个调查区域的空间变化。 层厚和层亮度数据的统计分析将能够预测：1）年际累积变化，2）由于累积空间模式的变化，层厚在十年尺度上的变化，以及3）由于微观结构空间模式的变化，微观结构驱动的变质作用的变化。有了这些统计数据，测量WAIS Divide冰芯中发现的气候变化的科学家将能够确定他们测量的信号超出背景累积变化引起的信号的比例。作为一个额外的好处，而仍然在外地，我们将确定一个初步的深度年龄规模的积雪光学层计数，最深的充气积雪洞的深度。这将是一个有价值的结果，为岩心钻探作业和初步的数据分析的核心。就更广泛的影响而言，该项目将通过培训一名实地技术博士后来促进教育。私家侦探博士后研究员将参加一个名为“什么是科学研究？“，包括该项目的进展和成果。他们还将与中学科学和数学班交流他们的进展和实地经验。

0538639WaddingtonThis award supports a project to study the patterns of accumulation variation and microstructural properties near the WAIS Divide ice core site in a 2.5 km array of 20 m boreholes. Borehole Optical Stratigraphy (BOS) is a novel optical measurement system that detects annual-scale layers in firn that result from changes in firn microstructure, giving annual-scale records of how accumulation varied spatially over the last 40-50 years. Data from borehole optical stratigraphy can eventually be calibrated against other data on the microstructural parameters of firn to calibrate BOS's sensitivity to density, pore-volume, and pore-shape variations, and to show by proxy how these parameters vary in space across the survey area. Statistical analysis of layer-thickness and layer-brightness data will enable prediction of: 1) interannual accumulation variability, 2) variability in layer-thickness at decadal scales due to changing spatial patterns in accumulation and 3) variability in microstructure-driven metamorphism due to changing spatial patterns of microstructure. With these statistics in hand, a scientist measuring climatic shifts found in the WAIS Divide ice core will be able to determine the fraction by which signals they measure exceed the signal due to background accumulation variations. As an added benefit, while still in the field, we will determine a preliminary depth-age scale for the firn by optical layer-counting, to the depth of the deepest air-filled firn hole available. This will be a valuable result for core-drilling operations and for preliminary data-analysis on the core. In terms of broader impacts, this project will advance education by training a post-doctoral student in field techniques. The P.I. and the post-doctoral researcher will participate in an undergraduate seminar called "What is Scientific Research?", incorporating progress and results from this project. They will also communicate about their progress and field experience with a middle-school science and math class.