Spatial Variability of Relative Sea-Level Rise in Tianjin, China: Insight From InSAR, GPS, and Tide-Gauge Observations
Spatial Variability of Relative Sea-Level Rise in Tianjin, China: Insight From InSAR, GPS, and Tide-Gauge Observations
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DOI：
10.1109/jstars.2021.3054395
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发表时间：
2021
影响因子：
5.5
通讯作者：
Wei Tang;Wei Zhan;Bowen Jin;M. Motagh;Yubin Xu
中科院分区：
文献类型：
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作者：
Wei Tang;Wei Zhan;Bowen Jin;M. Motagh;Yubin Xu
位于中国北部渤海湾的天津沿海地区正日益受到风暴潮洪水的影响，人为地面沉降和全球海平面上升加剧了风暴潮洪水的影响。利用合成孔径雷达干涉测量(InSAR)、连续GPS(CGPS)和验潮仪观测相结合的方法，对天津海岸线相对单反(RSLR)的空间变异性进行了评价。对两个轨道的Sentinel-1合成孔径雷达图像和19个CGPS观测站进行的地面运动分析表明，天津市区近期的地面沉降量小于8 mm/年，与过去50年相比(20世纪80年代达到110 mm/年)有了显著的下降。这可能得益于南水北调工程，自2014年以来，该工程已为天津市提供了超过18亿立方米的水，并减少了地下水消耗。然而，下沉中心已经转移到郊区，特别是在以填海造港和水产养殖业为主的海岸线上，局部下沉高达170毫米/年。结合InSAR观测和验潮站的海平面记录，揭示了RSLR沿海岸线的空间变异性。我们发现，在沿海岸线的水产养殖区，由于开采地下水用于渔业，地面沉降率高达82毫米/年，从而导致当地海平面上升的速度比全球平均水平快近30倍。对地面沉降和当地SLR的新见解可能有助于该国监管机构就确保沿海水产养殖业的可持续发展做出决策。
The Tianjin coastal region in Bohai Bay, Northern China, is increasingly affected by storm-surge flooding which is exacerbated by anthropogenic land subsidence and global sea-level rise (SLR). We use a combination of synthetic aperture radar interferometry (InSAR), continuous GPS (CGPS), and tide-gauge observations to evaluate the spatial variability of relative SLR (RSLR) along the coastline of Tianjin. Land motion obtained by integration of 2 tracks of Sentinel-1 SAR images and 19 CGPS stations shows that the recent land subsidence in Tianjin downtown is less than 8 mm/yr, which has significantly decreased with respect to the last 50 years (up to 110 mm/yr in the 1980s). This might benefit from the South-to-North Water Transfer Project which has provided more than 1.8 billion cubic meters of water for Tianjin city since 2014 and reduced groundwater consumption. However, subsidence centers have shifted to suburbs, especially along the coastline dominated by reclaimed harbors and aquaculture industry, with localized subsidence up to 170 mm/yr. Combining InSAR observations with sea level records from tide-gauge stations reveals spatial variability of RSLR along the coastline. We find that, in the aquaculture zones along the coastline, the rates of land subsidence are as high as 82 mm/yr due to groundwater extraction for fisheries, which subsequently cause local sea levels to rise nearly 30 times faster than the global average. New insights into land subsidence and local SLR could help the country's regulators to make decisions on ensuring the sustainable development of the coastal aquaculture industry.