Article,
Remote sensing of ice motion in Antarctica – A review
Remote Sensing of Environment, (2020)
DOI: https://doi.org/10.1016/j.rse.2019.111595
Abstract
The Antarctic Ice Sheet holds ~91% of the global ice mass making it the biggest potential contributor to global sea-level-rise. In order to evaluate the ice sheet's present and future response to global climate change, detailed information about spatial and temporal ice mass dynamics is required. While ice sheet surface mass balance can be estimated from regional climate models, ice discharge is often determined from spaceborne measurements of ice thickness and ice motion at selected flux gates. The retrieval of ice motion is not only critical for analysing the rate of ice transport into the ocean but also for investigating the spatial and temporal pattern or the driving forcings of Antarctic ice flow dynamics. This study provides a comprehensive review of state-of-the-art spaceborne ice velocity measurements in Antarctica. Based on 201 scientific papers, published over the last three decades, our analysis revealed a dominant interest in local and regional scale investigations. Yet, the launch of the ERS-1/-2 and RADARSAT-1 SAR satellites in the 1990s dramatically increased data coverage over the Antarctic continent and enabled the first circum-antarctic velocity product to be published in the late 2000s. In recent years, the improved imaging capabilities of Landsat 8 led to a shift towards using mainly optical satellite data and enabled great advances in circum-antarctic velocity mapping. Data from the currently operating Sentinel-1/-2 missions was applied in fewer studies but will play a crucial role in future ice motion studies e.g. as part of ESA CCI projects. In addition, we found a growing interest in high temporal resolution velocity change analyses. Based on the reviewed studies, we moreover summarized the highly dynamic and locally variable flow pattern over the Antarctic continent being in accordance with varying local and regional driving mechanisms. Despite the great advances in spaceborne ice velocity mapping in Antarctica, we report some major drawbacks and discuss future challenges and requirements. To start with, our study uncovered strong variations regarding the spatial availability of investigations. While we found an aggregation of studies over selected glaciers, we report a major lack of studies in all three Antarctic sectors. Additionally, many velocity datasets were created with strongly heterogeneous output parameters and were provided at coarse temporal resolution or at point-based measurement locations only. Future studies should consequently aim at creating more uniform ice motion products at defined spatial and temporal coverage and resolution standards and at analysing particularly the least studied glaciers.
