The Uncertainty in InSAR-Based Active Layer Soil Water Storage Estimates Over the Arctic Foothills

We jointly analyzed 23 L-band ALOS PALSAR scenes and over 200 soil core samples collected near the Toolik region. Based on the fact that the maximum thaw subsidence is proportional to the total soil water content in the active layer, we derived an equivalent water depth map over the Toolik area using the InSAR thaw subsidence estimates. We quantified the noise terms in the InSAR measurements and demonstrated that the DEM error is the dominant error source in the study area, mostly in steep terrains. We developed a mitigation strategy that reduces the uncertainty in the InSAR-based soil water estimates from
$> 20\text{cm}$
to
$< 10\text{cm}$
. Our study suggests that InSAR has greater observational capabilities than previously assumed for monitoring the active layer soil water storage above continuous permafrost.