厦门岛历史围填海岸InSAR地表变形及其对相对海平面的影响OACHSSCD

Accurate assessment of the threat posed by relative sea-level rise to coastal cities urgently requires high-resolution data on land vertical deformation.However,in areas with a long history of land reclamation,the surface deformation rate is often assumed to be constant,neglecting the spatiotemporal variability of deformation caused by soil consolidation and human activities.This study,using Xiamen Island as an example,obtained a high-resolution surface deformation field using Sentinel-1 SAR images from 2015-2019 through PS-InSAR technology and established a decay model of surface deformation versus reclamation time.The results show that:(1)Surface deformation in the reclaimed areas of Xiamen Island exhibits significant spatial heterogeneity,with significant subsidence exceeding 5 mm/a still occurring in areas such as the western shore of Yuandang Lake and Gaoqi Airport;(2)The deformation rate in reclaimed areas is negatively correlated with reclamation time,typically stabilizing approximately 20 years after land reclamation is completed;(3)After correcting for land vertical movement,the relative sea-level rise rate in the Xiamen area is approximately 4.7 mm/a.Predictions to 2100 indicate that although tectonic uplift will cause the land to rise by approximately 7.8 cm overall,the extreme high water levels caused by relative sea-level rise still pose a serious threat to the reclaimed coastlines.This study emphasizes the need to consider the impact of high-resolution surface deformation and its spatiotemporal dynamics in coastal city risk assessment.