A Method of Repeat Photoclinometry for Detecting Kilometer-Scale Ice Sheet Surface Evolution

作者：Greene Chad A^*; Blankenship Donald D

来源：IEEE Transactions on Geoscience and Remote Sensing, 2018, 56(4): 2074-2082.

DOI：10.1109/TGRS.2017.2773364

• Ice
• image sequence analysis
• photometry
• terrain mapping

Small-scale glaciological processes can drive large-scale ice sheet behavior but remain underreported due to a paucity of surface elevation measurements in remote polar regions. Satellite images provide a relatively long record of spatially dense surface observations, which allow us to investigate changes in ice sheet topography on the spatial scales of 1-10 km. Inferring surface topography from satellite images is an established technique, but in previous efforts, strict requirements for illumination conditions and image quality have led to a great quantity of discarded data. Relaxing quality requirements and fitting linear trends to the time series of image-derived surface topography allow inclusion of more total signal and enable blending data from multiple platforms. As a proof of concept, we combine 121 MODerate-resolution Imaging Spectroradiometer images to develop a 250-m resolution map of surface elevation change at Totten Glacier, Antarctica achieving a 1-sigma uncertainty of 0.22 m a(-1) for a 15-year period. Our method of repeat photoclinometry agrees with repeat laser altimetry while revealing clear patterns of surface elevation change associated with ice advection, channelized ice shelf basal melt, subglacial lake activity, and possible grounding line migration.

• 出版日期2018-4