Surface-Height Determination of Crevassed Glaciers—Mathematical Principles of an Autoadaptive Density-Dimension Algorithm and Validation Using ICESat-2 Simulator (SIMPL) Data
Surface-Height Determination of Crevassed Glaciers—Mathematical Principles of an Autoadaptive Density-Dimension Algorithm and Validation Using ICESat-2 Simulator (SIMPL) Data
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DOI：
10.1109/tgrs.2016.2617323
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发表时间：
2017-02
影响因子：
8.2
通讯作者：
U. Herzfeld;T. Trantow;D. Harding;P. Dabney
中科院分区：
文献类型：
--
作者：
U. Herzfeld;T. Trantow;D. Harding;P. Dabney
冰川加速是海平面变化评估中不确定性的主要来源。测量冰面高度的空间和时间分辨率，不仅允许海拔变化计算，但也捕捉冰面形态及其变化是必要的，以帮助调查的地球物理过程与冰川加速。美国宇航局未来的ICESat-2使命（2017年发射）上的先进地形激光高度计系统将实施多光束微脉冲光子计数激光雷达高度测量，旨在测量沿轨道间距为0.7米的冰面高度。该仪器旨在解决迅速变化的冰川和冰盖以及北极海冰的空间和时间变异性。新技术要求开发一种新的数学算法来检索高度信息。我们介绍的密度维算法（DDA），利用径向基函数计算的加权密度作为一种形式的数据聚合的光子云，并认为密度的一个额外的维度作为一种援助，在自适应阈值确定。该算法的自适应能力是必要的，以在不断变化的环境条件下将回波与噪声和信号光子分离。该算法使用ICESat-2模拟器仪器，斜坡成像多极化光子计数激光雷达，在格陵兰岛西北部的严重裂缝Giesecke Brær在2015年夏天收集的数据进行评估。结果表明，ICESat-2有望提供裂缝冰川和其他复杂冰面上的冰面高度测量。DDA一般适用于机载和星载微脉冲光子计数的分析|复杂和简单表面上的激光雷达数据。
Glacial acceleration is a main source of uncertainty in sea-level-change assessment. Measurement of ice-surface heights with a spatial and temporal resolution that not only allows elevation-change calculation, but also captures ice-surface morphology and its changes is required to aid in investigations of the geophysical processes associated with glacial acceleration. The Advanced Topographic Laser Altimeter System aboard NASA’s future ICESat-2 Mission (launch 2017) will implement multibeam micropulse photon-counting lidar altimetry aimed at measuring ice-surface heights at 0.7-m along-track spacing. The instrument is designed to resolve spatial and temporal variability of rapidly changing glaciers and ice sheets and the Arctic sea ice. The new technology requires the development of a new mathematical algorithm for the retrieval of height information. We introduce the density-dimension algorithm (DDA) that utilizes the radial basis function to calculate a weighted density as a form of data aggregation in the photon cloud and considers density an additional dimension as an aid in autoadaptive threshold determination. The autoadaptive capability of the algorithm is necessary to separate returns from noise and signal photons under changing environmental conditions. The algorithm is evaluated using data collected with an ICESat-2 simulator instrument, the Slope Imaging Multi-polarization Photon-counting Lidar, over the heavily crevassed Giesecke Brær in Northwestern Greenland in summer 2015. Results demonstrate that ICESat-2 may be expected to provide ice-surface height measurements over crevassed glaciers and other complex ice surfaces. The DDA is generally applicable for the analysis of airborne and spaceborne micropulse photon-counting| lidar data over complex and simple surfaces.