联合升降轨Sentinel-1A的地表形变监测技术研究

河谷型、海岸带、海岛礁以及滩涂等区域地表形变信息的准确获取,迫切且关键。利用25景升轨和28景降轨Sentinel-1A数据,基于SBAS-InSAR技术,获取兰州城区2014年10月~2016年9月的地表沉降速率图和沿视线方向(line-of-sight,LOS)的时相位移量,探讨升降轨数据在河谷型城市地表形变监测中的适用性。结果表明:升降轨Sentinel-1A数据之间的时相位移量具有高度关联性,其中升轨数据在地形起伏较大区体现出良好的干涉性,而降轨数据在平坦区表现出较好的监测能力。兰州城区大部分区域处于稳定状态,但沙井驿、九州、小达坪、东岗、伏龙坪、西客站以及周边区域地表存在沉降趋势,最大沉降速率可达30 mm/年。联合升降轨Sentinel-1A数据监测河谷型、海岸带、海岛礁以及滩涂等区域地面沉降具有可行性和可靠性。

Research on Ground Deformation Monitoring Technique of Jointing Ascending and Descending Sentinel-1A

The accurate acquisition of ground deformation information in valley type,coastal zone,island reef and tidal flat is urgent and critical.In this paper,based on Sentinel-1A data of 25 ascending and 28 descending orbits,deformation velocity maps and line-of-sight (LOS) time series displacement of Lanzhou urban area from October 2014 to September 2016 were obtained by using SBAS-InSAR technique,and the applicability of ascending and descending orbit data in the monitoring of ground deformation in valley cities were discussed.The results show that the time series displacement between ascending and descending orbits of Sentinel-1A data is highly correlated.The ascending data show good interference in large undulating areas of topography,while the descending data show good monitoring capability in flat urban areas.Most of the urban areas in Lanzhou are in a stable state,but there is a trend of surface subsidence in Shajingyi,Jiuzhou,Xiaodaping,Donggang,Fulongping,West Railway Station and the surrounding areas.The maximum subsidence rate can reach 30mm/a.It is feasible and reliable to monitor land subsidence in valley,coastal zone,island reef and tidal flat with Sentinel-1A data of jointing ascending and descending orbits.