Collapse of an Antarctic ice shelf and its flow velocity changes has the potential to reduce the restraining stress to the seaward flow of the Antarctic Ice Sheet, which can cause sea level rising. Remote Sensing research group of KOPRI analyzed variations in ice velocity from 2000 to 2017 for the Nansen Ice Shelf in East Antarctica that experienced a large-scale collapse in April 2016 using Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-8 Operational Land Imager (OLI) images.
Lansat-8 OLI panchromatic image of Nansen Ice Shelf obtained on 2 January 2014. The grounding line is shown as the red line. The white box represents the region of ice velocity measurement by Landsat multispectral image matching. The yellow line indicates the rift.
To extract ice velocity, image matching based on orientation correlation was applied to the image pairs of the Landsat multispectral data, from which the results were combined.
The ice velocity magnitude of Nansen Ice Shelf in 2000 (left) and 2017 (right) obtained from Landsat. The arrows represent the local flow direction.
The ice velocity along the central flow line of the Nansen Ice Shelf was stable before 2010 (~228 m/year). In 2011-2012, when a rift began to develop near the ice front, the ice flow was accelerated (~255 m/year) but the velocity was only about 11% faster than 2010. Since 2014, the massive rift had been fully developed, and the ice velocity of the upper region of the rift slightly decreased (~225 m/year) and stabilized. This means that the development of the rift and the resulting collapse of the ice front had little effect on the ice velocity of the Nansen Ice Shelf.
Landsat panchromatic images obtained during the development of the rift near the ice front of Nansen Ice Shelf.