InSAR estimation of permafrost active layer thickness considering soil conduction-convection heat transfer effect
The change of permafrost active layer thickness(ALT)is an important index to reflect the development and status of permafrost in Tibetan Plateau.Monitoring the change of ALT is of great significance to the stable development of the cold region landscape,carbon cycle,etc.Since the Interferometric Synthetic Aperture Radar(InSAR)technology has the advantages of large range,high precision and high spatial-temporal resolution,it has been gradually used to invert ALT in recent years.The existing ALT estimation methods based on InSAR and one-dimensional heat transfer model of soil do not fully consider the heat transfer caused by soil moisture convection in permafrost.Therefore,this paper presents a method to estimate ALT over permafrost based on InSAR observation and soil conduction-convection heat transfer model.Using the time lags between the maximum periodic feature of InSAR-observed surface deformation over permafrost and maximum land surface temperature,the correlation between time lags and ALT is established based on the soil conduction-convection heat transfer model.Finally,by exploiting the time lags and the soil conduction-convection heat transfer model,we estimate the large-scale and high-resolution ALTs.Taking Wudaoliang permafrost region of Tibetan Plateau as an example,116 Sentinel-1 images are exploited by the method to estimate average ALT in this region from 2017 to 2020.In the case study,the ALTs are ranging from 0 to 7.0 m and with an average of 3.06 m.The results are compatible with those related observations and estimations in existing studies.Our results demonstrate that soil conduction-convection heat transfer model has good prospect in ALT estimation over permafrost regions.The presented method takes into account the hydrothermal process of permafrost and can potentially be used for deriving high-resolution ALTs in other remote areas similar to Tibetan Plateau.
PermafrostSoil conduction-convection heat transfer modelTibetan PlateauActive layer thickness(ALT)InSAR
万方数据
维普
