Collaborative Research: Testing Next Generation Measurement Techniques for Reconstruction of Paleoclimate Archives from Thin or Disturbed Ice Cores Sections

冰芯提供了过去气候的宝贵记录，例如大气中温室气体的浓度，以及过去气候突然变化的无与伦比的证据。了解过去气候变化的关键是对用于确定冰层年龄的年层的测量，以及重大气候事件的时间和节奏。目前对冰芯年层的测量极限是厘米级。该项目旨在利用电导率、高光谱成像、激光消融测量的主要元素和冰粒特性等测量方法来提高冰中化学杂质测量的深度分辨率。这将促进对冰芯保存和分层的了解，并提高现有冰芯年度时间尺度的准确性和长度。过去保存在冰芯中的大部分时间都在海床附近，那里的冰层已经变薄到只有原来厚度的一小部分。随着项目的目标是基冰的气候记录，以及从蓝冰地区恢复的旧冰，解释冰芯高度压缩的部分变得越来越重要。该项目将精确地结合共同登记的电导率测量、高光谱成像、激光烧蚀杂质质谱仪测量以及冰的物理性质，以研究极地冰的亚厘米化学和物理变化。解决薄冰层的关键是了解可能掩盖或扭曲垂直分层的跨核变化。分析将侧重于WDC-06A(WAIS Divide)、SPC-14(南极)和GISP2(格陵兰冰盖项目2)冰芯的样本，这些冰芯具有明确的季节周期，产生基准时间尺度，以及来自Allan Hills蓝色冰区的大直径冰芯。这项工作将在国家科学基金会冰芯设施开发最先进的仪器和公平(可发现、可访问、可互操作和可重复使用)数据处理工作流程，供社区使用，以增进对现有冰芯的了解，并用于未来的项目。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ice cores provide valuable records of past climate such as atmospheric concentrations of greenhouse gasses and unmatched evidence of past abrupt climate change. Key to understanding past climate changes are the measurements of annual layers that are used to determine the age of the ice, and the timing and pace of major climate events. The current measurement limit for annual layers in ice cores is at the centimeter scale. This project aims to improve the depth resolution of measurements of the chemical impurities in ice using measurements such as electrical conductivity, hyperspectral imaging, major elements measured with laser ablation, and ice grain properties. This will advance understanding of the preservation and layering in ice cores and improve the accuracy and length of annual timescales for existing ice cores.Most of the past time preserved in an ice core is near the bed where the layers have been thinned to only a fraction of their original thickness. Interpreting highly compressed portions of ice cores is increasingly important as projects target climate records in basal ice, and old ice recovered from blue-ice areas. This project will integrate precisely co-registered electrical conductivity measurements, hyperspectral imaging, laser ablation mass spectrometer measurements of impurities, and ice physical properties to investigate sub-centimeter chemical and physical variations in polar ice. Critical to resolving thin ice layers is understanding the across-core variations that may obscure or distort the vertical layering. Analyses will be focused on samples from the WDC-06A (WAIS Divide), SPC-14 (South Pole), and GISP2 (Greenland Ice Sheet Project 2) ice cores that have well-established seasonal cycles that yielded benchmark timescales, as well a large-diameter ice core from the Allan Hills blue ice area. This work will develop state-of-the-art instrumentation and FAIR (findable, accessible, interoperable, and reusable) data handling workflow at the National Science Foundation Ice Core Facility available to the community both to enhance understanding of existing ice cores, and for use in future projects.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.