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

内陆 WAIS 核心站点钻孔光学地层学的云特性空间变化

• 批准号: 0538639
• 负责人: Edwin Waddington
• 金额: $ 8.5万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0538639&HistoricalAwards=false
• 关键词: Spatial; Variability; Firn; Properties; Borehole

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.

0538639Waddington 该奖项支持一个项目，研究 WAIS Divide 冰芯附近 2.5 公里阵列的 20 m 钻孔中的堆积变化模式和微观结构特性。 钻孔光学地层学 (BOS) 是一种新颖的光学测量系统，可检测因云层微观结构变化而产生的云层中的年度尺度层，从而提供过去 40-50 年累积量在空间上如何变化的年度尺度记录。来自钻孔光学地层学的数据最终可以根据岩石微观结构参数的其他数据进行校准，以校准 BOS 对密度、孔隙体积和孔隙形状变化的敏感性，并通过代理显示这些参数在整个勘测区域的空间变化情况。 对层厚度和层亮度数据的统计分析将能够预测：1）年际积累变异性，2）由于积累的空间模式变化而导致的年代际尺度的层厚度变异性，以及3）由于微观结构驱动的变质作用的变异性改变微观结构的空间模式。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到的信号超过由于背景累积变化而产生的信号的比例。作为一个额外的好处，当我们仍在现场时，我们将通过光学层计数来确定云杉的初步深度年龄尺度，直至可用的最深的充气云杉孔的深度。这对于岩心钻探作业和岩心初步数据分析来说将是一个有价值的结果。就更广泛的影响而言，该项目将通过培训现场技术的博士后来推进教育。 P.I.博士后研究员将参加一个名为“什么是科学研究？”的本科生研讨会，介绍该项目的进展和成果。他们还将在中学科学和数学课上交流他们的进步和现场经验。