Glacier Surface Speed Variations on the Kenai Peninsula, Alaska, 2014–2019

Abstract

To characterize the spatiotemporal variations of glacier surface speed on the Kenai Peninsula, Alaska (∼3,900 km2), we derived 92 surface speed fields between October 2014 and December 2019 using intensity offset tracking on Sentinel‐1 data. On average, speeds are 50% greater in spring (March‐May) than the annual mean (69 m a−1) while winter speeds are close to the annual mean. While marine‐terminating glaciers have their maximum speed near the terminus, both land‐ and lake‐terminating glaciers flow fastest around the median glacier elevation. On average, the lake‐terminating and tidewater glaciers flow 1.7 and 2.3 times faster than the land‐terminating glaciers, respectively. Monthly variations over the 5‐year period are strikingly synchronous regardless of terminus type suggesting that regional‐scale meteorological drivers govern the temporal variability. Mean annual speeds fluctuate roughly ±10% of the period mean without an apparent trend. At lake‐terminating Bear Glacier, a short‐term tripling in ice speed in fall 2019 over the area below an ice‐dammed lake coincides with an observed glacier lake outburst flood (GLOF). An earlier GLOF caused a persistent breach of the beach barrier between the proglacial lake and ocean which likely led to overall speed‐up of the lower glacier part throughout 2019. A significant speedup was also observed at the lower part of the lake‐terminating Ellsworth Glacier and attributed to rapid glacier retreat and lake expansion, probably further amplified by the terminus area becoming buoyant and a large tabular iceberg breaking off. Our results highlight the impact of GLOFs and proglacial characteristics in spatial and temporal glacier speed variations.

Variability of glacier velocity and the influencing factors in the Saint Elias Mountains, Southeastern Alaska

“…To investigate seasonal variations, we computed a factor named seasonal enhancement factor [17] for each pixel defined as the ratio of 3-month averaged velocity and the mean velocity over the 4-year study period. Rather than directly comparing the velocities of different seasons, this factor measures the degree for each pixel to which the velocities in different seasons are higher or lower than the pixel's period mean, e.g., the value of 1 represents that the seasonal velocity is equal to the period mean value.…”

Glacier Surface Velocity Variations in the West Kunlun Mts. with Sentinel-1A Image Feature-Tracking (2014–2023)

“…There are two fundamental methods for estimating glacier flow velocity using SAR images: D-InSAR and offset tracking. D-InSAR often has limited applicability when measuring fast glacial movements or long repetitive cycles, which lead to decorrelation [13,14]. By contrast, offset tracking of the intensity of SAR image pairs to estimate the displacements can partially overcome the shortage of image interference.…”

“…Milczarek et al [18] used Sentinel-1 to determine the annual velocity changes of tidewater glaciers in the Hornsund Fjord, and analyze the seasonal and transient variations. Yang et al [14] used the time series of Sentinel-1 data to determine the 69 surface velocity fields on the Neche Peninsula, Alaska, and analyze the differences in flow velocity variations among tidewater, lake, and land-terminating glaciers. Yang et al [14] also investigated the effects of glacial lake outburst flooding (GLOF) and other environmental factors on ice flow.…”

“…Yang et al [14] used the time series of Sentinel-1 data to determine the 69 surface velocity fields on the Neche Peninsula, Alaska, and analyze the differences in flow velocity variations among tidewater, lake, and land-terminating glaciers. Yang et al [14] also investigated the effects of glacial lake outburst flooding (GLOF) and other environmental factors on ice flow. Furthermore, Sentinel-1 offers a wide range of applications for monitoring glaciers in the HMA region.…”

A Wireless Real-Time Continuous Monitoring System for the Internal Movements of Mountain Glaciers Using Sensor Networks

“…Polar amplification can accelerate the shrinking of glaciers [ 7 , 8 ], since most glaciers exist at the Earth’s Third Pole and other mountain regions. The current shrinkage provides direct and unequivocal effects on water resources, and relative disasters occur with increasing intensity and frequency, such as ice avalanches, surging glaciers, and glacial lake outburst floods (GLOFs) [ 9 , 10 , 11 , 12 , 13 ]. However, how can we predict future glacial ice volumes and any related water resource changes?…”