Collaborative Research: Exploring the Dynamics of the Active Layer and Near-Surface Permafrost across the North Slope of Alaska

拟议研究的总体目标是利用干涉合成孔径雷达(InSAR)调查阿拉斯加北坡富冰永久冻土活动层和顶层的动态变化。我们将同时使用C波段和L波段的数据，这些数据是在过去二十年(1991年至2011年)期间获得的。更具体地说，(I)我们将实施InSAR冻土算法(InSAR FGA)来检测ALT和近地表冻土的变化，(Ii)我们将通过钻井、机械探测和地面穿透雷达(GPR)来研究ALT和近地表冻土中地冰含量的空间变化。这项实地工作获得的数据和信息也将用于InSAR FGA验证和校准，(Iii)结合InSAR FGA输出、野外数据和现有的气候数据，我们将调查阿拉斯加北坡活动层和近地表永冻层的时空变化和变化，及其对1991年至2011年气候变化的响应。拟议研究的预期结果将提供：(I)可用于区域规模活动层和冻土研究的经过验证的InSAR FGA；(Ii)ALT的时间序列及其在研究期间的变化；(Iii)阿拉斯加北坡ALT的长期(1991-2011年)平均值；(Iv)阿拉斯加北坡富冰永久冻土表层潜在的地面冰融化，其分辨率从数十米到数百米不等。这项研究的结果将是模型输入和验证的理想选择，并可用于评估北极人类基础设施面临的风险。这位博士后将通过在地球科学与工程暑期研究项目中指导一名本科生来获得教育经验，结果将通过NSIDC All About冻土网站以及在菲斯克天文馆和博尔德公共图书馆的讲座向公众传播。

The overall objective of the proposed research is to investigate changes in the dynamics of the active layer and the top layers of ice-rich permafrost on the North Slope of Alaska using InSAR (Interferometric Synthetic Aperture Radar). We will use both C-band and L-band data, acquired during the last two decades (1991-2011). More specifically, (i) we will implement the InSAR Frozen Ground Algorithm (InSAR FGA) to detect changes in ALT and near-surface permafrost, (ii) we will investigate spatial variations of ALT and ground ice content of the near-surface permafrost through drilling, mechanical probing, and ground penetration radar (GPR). Data and information obtained from this fieldwork will also be used for InSAR FGA validation and calibration, (iii) combining InSAR FGA outputs, field data, and available climate data, we will investigate spatial and temporal changes and variations of the active layer and near-surface permafrost and their response to climate change from 1991 through 2011 on the North Slope of Alaska. The expected results of the proposed research will provide (i) a validated InSAR FGA useful for regional-scale active layer and permafrost studies; (ii) time series of ALT and their changes over the study period, (iii) long-term (1991-2011) mean of ALT across the North Slope of Alaska, and (iv) potential ground-ice melting in the top layers of ice-rich permafrost across the North Slope of Alaska with a resolution of from tens of meters to hundreds of meters. The results from this study will be ideal for model inputs and validation and can be used to assess risk to human infrastructure in the Arctic. The postdoc Liu will gain educational experience by mentoring an undergraduate student in the Summer Research in Geoscience and Engineering program, and results will be disseminated to the public through the NSIDC All about Frozen Ground website and via lectures at the Fiske Planetarium and Boulder Public Library.