Extraction and Analysis of the Three-Dimensional Features of Crevasses in the Amery Ice Shelf Based on ICESat-2 ATL06 Data

Crevasse is an important characteristic of ice shelf internal structure, and also an important index to measure the stability of ice shelf. This study aims to detect crevasses from ICESat-2 data and obtain three-dimensional features of the crevasse. First, the change of along-track surface slope and the depth threshold is combined to obtain the crevasse bottom points and the crevasse edge points. Second, the distance between the crevasse bottom points and the fitted ice shelf surface by crevasse edge points is used as the crevasse bottom points depth. Third, the crevasse direction is judged by the strong and weak laser positions and the width is calculated by the crevasse edge points and crevasse direction. The Amery ice shelf (AIS) is chosen as the test area to validate the method by ATL06 data, combined with the Landsat-8 optical image. The depth of the crevasses in the AIS is about ranges from 2.0 to 60.0 m, and the width is mainly 400 to 1600 m, and the width and length of the L3 rift have dramatically changed, which is an indicator that the AIS is in a new calving cycle. The method in this article can accurately obtain three-dimensional information of the crevasses, find crevasses with abnormal changes in depth and width, and provide effective help for predicting the calving of the ice shelf.