###### Abstract  
In this work, we investigate the temporal evolution of ground deformation affecting the ocean-reclaimed lands of the Shanghai (China) megacity, from 2007 to 2016, by applying the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique known as the Small BAseline Subset (SBAS) algorithm. For the analysis, we exploited two sets of non-time-overlapped synthetic aperture radar (SAR) data, acquired from 2007 to 2010, by the ASAR/ENVISAT (C-band) instrument, and from 2014 to 2016 by the X-band COSMO-SkyMed (CSK) sensors. The long time gap (of about three years) existing between the available C- and X-band datasets made the generation of unique displacement time-series more difficult. Nonetheless, this problem was successfully solved by benefiting from knowledge of time-dependent geotechnical models, which describe the temporal evolution of the expected deformation affecting Shanghai's ocean-reclaimed platforms. The combined ENVISAT/CSK (vertical) deformation time-series were analyzed to gain insight into the future evolution of displacement signals within the investigated area. As an outcome, we find that ocean-reclaimed lands in Shanghai experienced, between 2007 and 2016, average cumulative (vertical) displacements extending down to 25 centimeters. deformation; interferometry; differential synthetic aperture radar interferometry; time series 201689110.3390/rs8110911110.3390/rs8110911110.3390/rs8110911110.3390/rs8110911110.3390/rs8110911110.3390/rs81109111110.3390/rs81109111110.3390/rs811091111111111111111111111  
airport runways, harbors, and underground facilities, thus, also resulting in a possible decrease in the height of sea walls. In particular, in China, about 1600 km\({}^{2}\) of new territories were reclaimed from 2002 to 2011 [8; 9; 10; 11]. One of the largest reclamation projects in China is the plan approved in Lingang New City (new name, Nanhui New City), which is a district of the Shanghai megacity (see Figure 1), under which about 130 km\({}^{2}\) of land were reclaimed from the sea from 2003 to 2006. The reclamation project is currently in progress, and there are plans to recover about 1000 km\({}^{2}\) of new lands from the Yangtze River by the end of 2020 [10]. Over the past few years, the coastal area of Lingang New City, which extends for about 300 km\({}^{2}\) (45% of which was reclaimed from intertidal wetlands), has been subjected to broad modifications in its geomorphology and urban environment. Due to land reclamation, two main inherent problems have arisen: (i) liquefaction; and (ii) ground settlements, both of which are responsible for serious failures and damage to infrastructures of reclaimed foundations [12; 13; 14]. Results of geotechnical analyses have revealed that such a settlement usually continues over the entire reclamation facility lifetime. Temporal evolution of settlements can be distinguished in a primary consolidation phase of alluvial deposits, in a long-term creep (secondary compression stage) of the alluvial deposits beneath the reclamation, and, finally, in a creep within the reclamation fill [14]. These settlements may occur during and after foundation construction, and, when not correctly predicted, can cause delays and a considerable increase in costs of the whole reclamation project. Ground settlement of reclaimed coastal areas in Shanghai, which is caused by over-pumping groundwater and consolidation of dredger fills and alluvial deposits, have already been observed and reported in the literature [15; 16; 17; 18; 19; 20]. In particular, field measurements indicate that ground settlement of the reclaimed foundations occurred during the construction of Lingang New City in Shanghai. Average cumulative (vertical) deformation values, ranging between 25 and 75 mm, in the six-year period from 2001 to 2006, corresponding to average annual rates ranging between 5 and 15 mm/year, have been measured [16].