Using interferometric synthetic aperture rader (InSAR) analysis to detect ground deformation related to irreversibly changing ground ice, Mongolia

Abstract

AbstractPermafrost in Mongolia shows highly heterogeneous features in space and the contents of ground ice are dependent on the local geographies such as topography, ground wetness, and vegetation cover. Recent permafrost degradation would cause thawing and disappearance of ground ice, destabilizing and subsiding the ground surface. This study aimed to detect topographic deformation related to irreversibly changing ground ice over the permafrost terrain of Mongolia. To end this we used interferometric synthetic aperture RADAR (InSAR) technique, which is capable to measure vertical ground deformation on a centimeter scale. Advanced land observing satellite‐based phased array type L‐band synthetic aperture radar (PALSAR) images (June to September 2007 to 2010) and PALSAR‐2 images (June to September 2014 to 2017) quantified near‐year‐round displacement of the ground surface. The overall deformation was in a range of −3 to 3 cm (subsidence and uplift, respectively) between the image interval and relatively high subsidence occurred during warm years. The areas experiencing consecutive uplift and subsidence correspond to ground underlain by ice‐rich soils, indicating the dominant roles of thawing and growing ground ice for local deformation over permafrost terrain. We discuss the relation of observed ground deformation trends with regional climate and local geohydrology that influence ground ice formation.