Abstract
Monitoring glacier dynamics is an effective approach for quantifying the response of the glaciers in cold arid mountainous areas to climate change. However, the quantification of short-term flow dynamics of the mountain glaciers in cold-dry climates has rarely been reported. This article investigated the intra-annual flow dynamics in terms of velocity and ice thickness changes on the Kunlun glacier, a mountain glacier in the cold-dry west Kunlun mountains, using spaceborne synthetic aperture radar (SAR) imagery. We applied the improved pixel-offset-tracking small-baseline-subset method (PO-SBAS) on ascending and descending Sentinel-1A SAR images acquired in 2017 and 2018 to estimate the three-dimensional (i.e., north–south, west–east, and vertical) velocity time series of the glacier. The vertical velocities were further decomposed into the surface-parallel-flow (SPF) and the nonsurface-parallel-flow (nSPF) components, which link glacier motion along glacier surface slope and internal ice deformation, respectively, to glacier thickness changes. Our findings show that the eastern branch of the glacier moved faster than the western branch. We inferred that a loss of ice thickness due to a previous surge on the western branch should be responsible for its slower flow. The nSPF rates are higher than the SPF rates in both branches, indicating that internal ice deformation primarily controls the changes in ice thickness. We also observed an apparent summer acceleration in the nSPF rates, which is likely caused by changes in subglacial hydrological conditions. This article highlights the potential uses of the improved PO-SBAS method of quantifying the flow dynamics of the glaciers in cold-dry mountain regions.
Highlights
G LACIER thickness continually changes due to ice flow, and to the accumulation and removal of ice mass at the glacier surface in response to changing climate [1]
Monitoring changes in glacier flow speed provides an effective and quantitative approach to estimating the ice thickness changes, allowing us to explore how glaciers respond to climate change, which is an important and timely research topic [2], [3]
We explored the intra-annual 3-D velocity time series for the Kunlun glacier using the pixel-offset-tracking small-baseline-subset method (PO-SBAS) method based on 51 ascending and descending Sentinel-1A synthetic aperture radar (SAR) images acquired between 2017 and 2018
Summary
G LACIER thickness continually changes due to ice flow, and to the accumulation and removal of ice mass at the glacier surface in response to changing climate [1]. Changes in glacier thickness result in thickening or steepening of the glacier surface, which in turn leads to changes in glacial flow speed. Monitoring changes in glacier flow speed provides an effective and quantitative approach to estimating the ice thickness changes, allowing us to explore how glaciers respond to climate change, which is an important and timely research topic [2], [3]. Due to the harsh climatic conditions in the glaciated regions, in situ ice flow measurements on the glacier surface are often severely limited. Spaceborne synthetic aperture radar (SAR) technique has been extensively used to measure flow velocities of the glaciers in mountainous areas worldwide over the two decades [4], [5]. Compared to conventional field surveys, SAR imaging can map ground surface motion over a large area, day and night, and under all weather conditions
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.