| Yunnan Province is an area where geological hazards such as landslides are frequent,and the frequency of geological hazards is increasing after being influenced by human activities,which is a great threat to people’s life and property.By using remote sensing technology to monitor the surface deformation data,we can quickly identify the prone areas,but the accuracy of identification is affected by various factors such as vegetation cover.In Yunnan Province,the vegetation cover is complex,and the analysis capability is insufficient or cannot accurately identify the surface deformation in the vegetated areas using conventional remote sensing measurements.The SAR data using InSAR technology has different waveband signals and has certain penetration ability to vegetation,but there is a lack of research on the accuracy of identifying deformation affected by vegetation.In this paper,we will investigate the monitoring accuracy of Sentinel 1 data in areas with different vegetation cover,and infer the penetration ability of C-band in areas with different vegetation cover.Therefore,this paper takes Jianshui County and Fugong County,which have a large difference in vegetation cover,as the study area,and conducts a study on deformation detection and hidden danger identification in two areas of Jianshui County and Fugong County by time-series InSAR technology-SBAS-InSAR technology.With the characteristics of low vegetation coverage in Jianshui County compared with high vegetation coverage in Fugong County,the monitoring accuracy of Sentinel 1 data is verified in the two areas respectively,and the influence of high and low vegetation coverage on the strength of C-band signal penetration ability is analyzed.The main findings of the paper are as follows:(1)The SBAS-InSAR technique was used to process the Sentinel 1 downlink data of Jianshui and Fugong counties to obtain the deformation rate information of Jianshui and Fugong counties.The results show that the SBAS-InSAR technique can monitor the spatial distribution of surface deformation in Jianshui and Fugong counties and obtain the information of annual deformation variables in Jianshui and Fugong counties.(2)The vegetation cover of Jianshui and Fugong counties was obtained by estimating Landsat8 data for April 2019 in Jianshui County and August 2019 in Fugong County,respectively,through the image element dichotomy method.The results showed that the overall vegetation cover of Jianshui County was 0.44 and the overall vegetation cover of Fugong County was 0.64,and the overall vegetation cover of Jianshui County was substantially lower than that of Fugong County.The contrast of vegetation cover between these two areas is quite obvious,and there is obvious deformation information in the area of vegetation cover difference,which is very suitable for studying the influence of vegetation cover on the accuracy of deformation area identification of Sentinel 1 data.(3)Comparing the SBAS identification results with the results of the verification of basic information of disaster potential sites by the Yunnan Geological Environment Monitoring Institute,the results show that the identification accuracy of Jianshui County is 79.629% and that of Fugong County is 75.926%,from the overall perspective,the identification accuracy of Jianshui County with low vegetation cover is higher than that of Fugong County with high vegetation cover,indicating that the level of vegetation cover directly affects the accuracy of identification From the local point of view,most of the unidentified deformations in the corresponding verification points are in places with higher vegetation cover.(4)In Fugong County with high vegetation coverage and dense vegetation,the identification accuracy of deformation exploration was affected by vegetation coverage.After analysis,it was found that vegetation coverage and identification accuracy were negatively correlated,that is,the higher the vegetation coverage,the lower the identification accuracy.When the vegetation coverage was below 40%,the identification accuracy was above 75.34%;when the vegetation coverage was greater than 60%,the identification accuracy was above 75.34%.The recognition accuracy is less than 51.60%;It also shows that C-band signal has better penetration when the vegetation coverage is lower than 40%.When the vegetation coverage is higher than60%,its penetration ability is greatly weakened. |
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