Active Layer Thickness Retrieval Over the Qinghai-Tibet Plateau From 2000 to 2020 Based on Insar-Measured Subsidence and Multi-Layer Soil Moisture

Abstract

Abstract. Active layer thickness (ALT) is an important index to reflect the stability of permafrost. The retrieval of ALT based on Interferometric Synthetic Aperture Radar (InSAR) technology has been investigated recently in permafrost research. However, most of such studies are carried out in a limited extend and relatively short temporal coverage. The combination of temporal-spatial multi-layer soil moisture data and multi-temporal InSAR is a promising approach for the large-scale characterization of ALT. In this study, we employed Small Baseline Subset Interferometry (SBAS-InSAR) technology to obtain the seasonal surface deformation from radar images of Envisat and Sentinel-1 in a permafrost region of Qinghai-Tibet Plateau (QTP). We attempt to verify and calibrate the temporal-spatial multi-layer soil moisture product in combination with the in-situ data. Based on the land subsidence data and the temporal-spatial multi-layer soil moisture data, we further improve method to retrieve the ALT information. This paper describes the progress so far and point out the future work.

Thaw Settlement Monitoring and Active Layer Thickness Retrieval Using Time Series COSMO-SkyMed Imagery in Iqaluit Airport

“…The retrieval of ALT from surface displacement measurements detected by the InSAR has been promising due to the technique's capability for accurately mapping ground displacements on the scale of millimeters to centimeters [16][17][18][19][20]. There are two main types of ALT retrieval methods from InSAR-derived subsidence maps.…”

“…Considering the difficulty in measuring the time intervals directly, the model replaces them with the lag time between the periodic feature of InSAR-observed surface deformation over permafrost and the meteorologically recorded temperatures. The second method is based on the idea that the volume change from ice to the water of the AL leads to surface subsidence [17][18][19][20][21][22]. It can be represented by the Stefan formula or the Berggren model.…”