Elevation changes of bering glacier system, Alaska, from 1992 to 2010, observed by satellite radar altimetry

摘要

Satellite radar altimetry has been extensively used to estimate ice-sheet elevation change rates over Antarctica and Greenland from repeated measurements of surface elevation changes through either crossover or collinear (repeat-track) analysis. However, there has been no attempt to use satellite radar altimetry over mountain glaciers because the instrument often loses lock or does not provide usable measurements over the rough terrains and steep slopes due to its large footprint size. In this study, we demonstrate the feasibility of satellite radar altimetry to estimate elevation change rates over the Bering Glacier System in Alaska for the period of 1992-2010 from TOPEX/Poseidon and Envisat radar altimeter measurements. We are able to observe the 1993-1995, and 2008-2011 surge events from the T/P and Envisat time series, respectively. We also observe the accelerated elevation decreases in 2002-2007, after slightly negative or near nil elevation changes in 1996-2001, which are related to the temperature and snow depth variations. Our method can be applied to other wide (>. 7. km) glaciers worldwide, and provide new insights into the behavior of glaciers responding to climate change.