Abstract
This article presents an assessment of the horizontal accuracy and precision of the laser altimetry observations collected by NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) mission. We selected the terrain-matching method to determine the position of laser altimeter profiles within a precisely known surface, represented by a digital elevation model (DEM). We took this classical approach a step further, approximated the DEM by planar surfaces, and calculated the optimal position of the laser profile by minimizing the square sum of the elevation differences between reference DEMs and ICESat-2 profiles. We found the highly accurate DEMs of the McMurdo Dry Valleys (DV), Antarctica, ideal for this research because of their stable landscape and rugged topography. We computed the 3-D shift parameters of 379 different laser altimeter profiles along two reference ground tracks collected within the first two years of the mission. Analyzing these results revealed a total geolocation error (mean +1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> ) of 4.93 m for version 3 and 4.66 m for version 4 data. These numbers are the averages of the six beams, expressed as mean +1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sigma $ </tex-math></inline-formula> and lie well within the mission requirement of 6.5 m.
Highlights
N ASA launched the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2), the successor of ICESat, on September 15, 2018 [1]
The prime objective of this paper is to assess the horizontal accuracy of ICESat-2
We have improved the traditional method of matching a laser profile with a precisely known surface, likely being represented as a Digital Elevation Models (DEMs), by casting it as a least-squares adjustment
Summary
N ASA launched the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2), the successor of ICESat, on September 15, 2018 [1]. ICESat-2 carries the ATLAS (Advanced Topographic Laser Altimeter System) instrument, the first photon-counting lidar system for the purpose of elevation measurements from space [2]. The ATLAS observations enable the estimation of ice-sheet mass balance and corresponding contributions to sea level rise [3]. High accuracy of single-photon geolocation is needed to achieve the mission’s primary goal of monitoring land-ice elevation (ice sheet and glaciers) and sea-ice freeboard changes on a centimeter-scale level. Considering the large extent of the Antarctic ice sheets these stringent mission requirements are necessary because small changes in surface height have a considerable impact on mass balance and sea level change estimates. The mission requirement of 0.4 cm/yr for icesheet elevation change rates corresponds to 51 Gt/yr which
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More From: IEEE Transactions on Geoscience and Remote Sensing
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