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 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, in regions. This study validates SAR-derived estimates three regions Alaska, USA using calibrated ground penetrating (GPR) geophysical data. The remotely sensed matched field within uncertainty 79% locations. average GPR-derived validation dataset was 0.14 m while pixels coincident with GPR data 0.19 m. region near Utqiaġvik, appeared slightly larger than Yukon-Kuskokwim Delta region, smaller observations. northern foothills Brooks Range, Toolik Lake, there minimal bias between estimates. These findings suggest that compare well situ probing GPR, making SAR an effective tool to monitor