Validation of Permafrost Active Layer Estimates from Airborne SAR Observations

In permafrost regions, active layer thickness (ALT) observations measure the effects of climate change and predict hydrologic and elemental cycling. Often, ALT is measured through direct ground-based measurements. Recently, synthetic aperture radar (SAR) measurements from airborne platforms have eme...

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Bibliographic Details
Published in:Remote Sensing
Main Authors: Andrew D. Parsekian, Richard H. Chen, Roger J. Michaelides, Taylor D. Sullivan, Leah K. Clayton, Lingcao Huang, Yuhuan Zhao, Elizabeth Wig, Mahta Moghaddam, Howard Zebker, Kevin Schaefer
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2021
Subjects:
active layer
permafrost
ground penetrating radar
synthetic aperture radar
Science
Q
Northern Foothills
Yukon
Active layer thickness
Brooks Range
Kuskokwim
Alaska
Online Access:https://doi.org/10.3390/rs13152876
https://doaj.org/article/7fff84f1901a44029e35f2ec4d9bf144
Description
Summary:In permafrost regions, active layer thickness (ALT) observations measure the effects of climate change and predict hydrologic and elemental cycling. Often, ALT is measured through direct ground-based measurements. Recently, synthetic aperture radar (SAR) measurements from airborne platforms have emerged as a method for observing seasonal thaw subsidence, soil moisture, and ALT in permafrost regions. This study validates airborne SAR-derived ALT estimates in three regions of Alaska, USA using calibrated ground penetrating radar (GPR) geophysical data. The remotely sensed ALT estimates matched the field observations within uncertainty for 79% of locations. The average uncertainty for the GPR-derived ALT validation dataset was 0.14 m while the average uncertainty for the SAR-derived ALT in pixels coincident with GPR data was 0.19 m. In the region near Utqiaġvik, the remotely sensed ALT appeared slightly larger than field observations while in the Yukon-Kuskokwim Delta region, the remotely sensed ALT appeared slightly smaller than field observations. In the northern foothills of the Brooks Range, near Toolik Lake, there was minimal bias between the field data and remotely sensed estimates. These findings suggest that airborne SAR-derived ALT estimates compare well with in situ probing and GPR, making SAR an effective tool to monitor permafrost measurements.

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