摘要
The freezing-thawing processes of permafrost would destroy geological environment,and then result in rupture and collapses of buildings and roads,landslides,floods and the movement of glaciers,etc.Therefore,it is very important to monitor the ground deformation in the permafrost region for the stability and security of structures as well as development of economy.At present,there is no effective method for monitoring time deformation evolution of permafrost within large area.In this paper,we propose combination of small baseline subset(SBAS) technology for the measurements of deformation time series of permafrost.Considering that the deformation of permafrost is characterized by seasonal oscillation,a periodic model is introduced to replace the linear model in the conventional SBAS in order to better eliminate the effects of topographic residuals and atmospheric artifacts.21 ASAR images acquired by the ENVISAT satellite are exploited by this method to monitor temporal evolutions of permafrost seasonal oscillation between 2007 and 2011 in the Qinghai-Tibet Plateau from Yangbajian to Damxung.By comparing with the field temperatures,it is found that the retrieved deformation sequences conform to physical characteristics of permafrost very well.The results demonstrate that SBAS-InSAR algorithm has good prospect in deformation monitoring over permafrost regions.