Innovative Method of Combing Multidecade Remote Sensing Data for Detecting Precollapse Elevation Changes of Glaciers in the Larsen B Region, Antarctica

The Antarctic Peninsula has undergone dramatic changes in recent decades, including ice-shelf melting, disintegration, and retreat of the grounding line. The Larsen B ice shelf is of particular concern due to the unprecedented ice-shelf collapse in 2002. Since few observations on the Antarctic Peninsula were available before the 1970s, long-term investigation of the surface elevation change in the Larsen B region could not be pursued. In 1995, the United States administration declassified a collection of archived intelligence satellite photographs from the 1960s to the 1970s, including analogue satellite images from the ARGON program covering parts of the Larsen B region. We chose overlapping ARGON photos captured in the Larsen B region in 1963. These photos were all subjected to a tailored photogrammetric stereo-matching process, which overcomes those specific challenges related to the use of historical satellite images, such as poor image quality, low resolution, and a lack of high-precision validation data. We discovered that between 1963 and 2001, the surface elevations of the main tributary glaciers in the Larsen B embayment have undergone little change before the ice shelf collapse from 1963 to 2001 by comparing the reconstructed ARGON-derived digital elevation model (DEM) (1963) and ASTER-derived DEM (2001). In addition, the results demonstrated that the hierarchical image matching method can be modified and applied to reconstruct a historical Antarctic DEM using satellite images acquired ∼60 years ago through an innovative and rigorous ground control point selection procedure that guarantees no changes occurred at these points over the period. The new ARGON-derived DEM derived from ARGON (1963) can be used to build a long-term spatiotemporal record of observations for extended analyses of ice-surface dynamics and mass balance in the Larsen B region.