Toward long-term monitoring of regional permafrost thaw with satellite interferometric synthetic aperture radar

Active-layer thickness (ALT) is estimated for a study area in northern Alaska's continuous-permafrost zone using satellite data from Sentinel-1 (radar) and ICESat-2 (lidar) for the period 2017 to 2022. Synthetic aperture radar (SAR) interferograms were generated using the Short Baseline Subset...

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Bibliographic Details
Published in:The Cryosphere
Main Authors: T. Sadeghi Chorsi, F. J. Meyer, T. H. Dixon
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2024
Subjects:
Environmental sciences
GE1-350
Geology
QE1-996.5
Active layer thickness
Ice
permafrost
The Cryosphere
Alaska
Online Access:https://doi.org/10.5194/tc-18-3723-2024
https://doaj.org/article/ed57b56d62a54d5baea68da65681baf5
Description
Summary:Active-layer thickness (ALT) is estimated for a study area in northern Alaska's continuous-permafrost zone using satellite data from Sentinel-1 (radar) and ICESat-2 (lidar) for the period 2017 to 2022. Synthetic aperture radar (SAR) interferograms were generated using the Short Baseline Subset (SBAS) approach. Displacement time series over the thaw season (June–September) are fit well with a linear model (root mean square error (RMSE) scatter is less than 7 mm ) and show maximum seasonal subsidence of 20–60 mm . ICESat-2 products were used to validate the interferometric synthetic aperture radar (InSAR) displacement time series. ALT was estimated from measured subsidence using a widely used model exploiting the volume difference between ice and water, reaching a maximum depth in our study area of 1.5 m . Estimated ALT is in good agreement with in situ and other remotely sensed data but is sensitive to assumed thaw season onset, indicating the need for reliable surface temperature data. Our results suggest the feasibility of long-term permafrost monitoring with satellite InSAR. However, the C-band ( ∼55 mm center wavelength) Sentinel radar is sensitive to vegetation cover and, in our studies, was not successful for similar monitoring in the heavily treed discontinuous-permafrost zone of central Alaska.

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