Localized uplift, widespread subsidence and implications for sea level rise in the NYC Metropolitan Area

Regional relative sea level rise is exacerbating flooding hazards in the coastal zone. In addition to changes in the ocean, vertical land motion (VLM) is a driver of spatial variation in sea-level change that can either diminish or enhance flood risk. Here we apply state-of-the-art Interferometric Synthetic Aperture Radar (InSAR) and global navigation satellite system (GNSS) time-series analysis to estimate velocities and corresponding uncertainties at 30 m resolution in the New York City Metropolitan Area, revealing VLM with unprecedented detail. We find broad subsidence of 1.6 mm/yr consistent with glacial isostatic adjustment to the melting of the former ice sheets, and previously undocumented hotspots of both subsidence and uplift that can be physically explained in some locations. Our results inform ongoing efforts to adapt to sea-level rise and reveal points of VLM that motivate both future scientific investigations into surface geology and assessments of engineering projects.

区域相对海平面上升正加剧沿海地带的洪涝灾害风险。除海洋自身变化外，垂直陆地运动（vertical land motion, VLM）是引发海平面变化空间差异的驱动因子之一，其既可能削弱也可能加剧洪涝风险。本研究采用当前前沿的合成孔径雷达干涉测量（Interferometric Synthetic Aperture Radar, InSAR）与全球导航卫星系统（global navigation satellite system, GNSS）时序分析方法，针对纽约都会区以30米分辨率估算垂直陆地运动速度及其对应不确定度，以空前精细的尺度揭示了该区域的垂直陆地运动特征。研究发现区域整体以1.6毫米/年的速率沉降，该现象与末次冰期冰盖消融引发的冰川均衡调整相符；同时还识别出此前未被记录的沉降与抬升热点区域，其中部分区域的异常运动可通过物理机制得到合理解释。本研究结果可为当前应对海平面上升的适配性工作提供科学参考，同时也明确了需开展后续地表地质科学研究与工程项目评估的垂直陆地运动关键点位。