Marginal weakening promoted rift propagation of the Petermann Ice Shelf in northwestern Greenland from 2016 to 2022  

作　　者：LI Daan JIANG Liming HUANG Ronggang LU Xi 

机构地区：[1]School of Urban and Reginal Planning,Yancheng Teachers University,Yancheng 224002,China [2]State Key Laboratory of Geodesy and Earth’s Dynamics,Innovation Academy for Precision Measurement Science and Technology,Chinese Academy of Sciences,Wuhan 430077,China [3]College of Earth and Planetary Science,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Advances in Polar Science》2023年第3期220-231,共12页极地科学进展（英文版）

基　　金：funded by the National Key R&D Program of China (Grant nos. 2018YFC1406102, 2017YFA0603103);the grand from State Key Laboratory of Geodesy and Earth's Dynamics (Grant no. SKLGED2022-2-2)。

摘　　要：Ice-shelf rifts are precursors of glacier calving, and thus they serve as indicators of ice shelf instability, especially under oceanic and atmospheric warming conditions. Therefore, understanding the dynamic processes underlying rift propagation and the associated damage mechanisms is essential to evaluate ice-shelf instability and to predict glacier calving. In this study, we investigated the effect of marginal weakening on rift propagation on the ice shelf of the Petermann Glacier, among the largest in Greenland, during 2016-2022. First, we analyzed satellite optical images to monitor rift growth(length and width) by tracking the tip trajectory of three large rifts identified on the Petermann Ice Shelf. Then, we estimated rift depth using ArcticDEM and ICESat-2 data. Our results indicated consistent increases of the rift widths and depths over the study period, with mean values of 133 m·a^(-1) and 0.3 m·a^(-1), respectively. We also combined remote-sensing observations with an ice-sheet numerical model to calculate the stress and damage fields on the Petermann Ice Shelf and to assess the ice shelf margin stability and strength. We determined that damage and lateral shear in the fracture zone degraded ice shelf integrity by decreasing the contact length with the fjord wall. In conclusion, marginal weakening effectively promoted rift propagation on the Petermann Ice Shelf, increasing the risk of future glacier calving.

关 键 词：rift propagation marginal weakening remote sensing damage mechanism 

分 类 号：P343.6[天文地球—水文科学]