Abstract Wetland is a very fragile ecosystem that provides important services to a large variety of flora and fauna species, as well as for humans. As wetland depends on water availability, protecting this important ecosystem requires careful hydrological monitoring. The Sentinel-1 mission, featuring a wide swath coverage, high temporal observations and open data policy, provides unprecedented opportunity for high spatio-temporal resolution water level change mapping over regional-wide wetland areas. In this study, we assess Sentinel-1 InSAR observations for routine water level change measurements over the entire south Florida Everglades wetlands. The study utilizes 91 Sentinel-1 images acquired over a three-year period (Sep 2016 to Nov 2019) and generates routine 12-days Interferograms and correspondingly 30 m spatial resolution water level change maps over the entire Everglades. The high spatial resolution interferograms detect hydrological signals induced by both natural- and human-induced flow, including tides, gate operations, and canal overflow; all these cannot be detected by terrestrial measurements. The large number of both InSAR and ground-based gauge observations allow us to quantify the overall accuracy of the Sentinel-1 InSAR measurements, which is 3.9 cm for the entire wetland area, but better for smaller hydrological units within the Everglades. Our study reveals that the tropospheric delay for individual interferograms can be very large, as much as 30 cm (~10 fringes). When applying tropospheric corrections to all three years of Sentinel-1 InSAR observations, the overall accuracy level improved by 13% to 3.4 cm. Although our study is focused on the Everglades, its implications in term of the suitability of Sentinel-1 observations for space-based hydrological monitoring of wetlands and the derived accuracy level are applicable to other wetlands with similar vegetation types, located all over the world.

中文翻译：

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使用 Sentinel-1 InSAR 观测对湿地进行区域尺度水文监测：南佛罗里达大沼泽地的案例研究

摘要 湿地是一个非常脆弱的生态系统，它为各种动植物物种以及人类提供重要服务。由于湿地取决于可用水量，因此保护这一重要的生态系统需要仔细的水文监测。Sentinel-1 任务具有宽幅覆盖、高时间观测和开放数据政策，为区域湿地区域的高时空分辨率水位变化绘图提供了前所未有的机会。在这项研究中，我们评估了 Sentinel-1 InSAR 对整个南佛罗里达大沼泽地湿地的常规水位变化测量的观测。该研究利用了三年期间（2016 年 9 月至 2019 年 11 月）获取的 91 张 Sentinel-1 图像，并生成了整个大沼泽地的常规 12 天干涉图和相应的 30 m 空间分辨率水位变化图。高空间分辨率干涉图检测由自然和人为流动引起的水文信号，包括潮汐、闸门操作和运河溢流；所有这些都无法通过地面测量检测到。大量 InSAR 和地面测量仪观测使我们能够量化 Sentinel-1 InSAR 测量的整体精度，整个湿地区域为 3.9 厘米，但对于大沼泽地内较小的水文单位来说更好。我们的研究表明，单个干涉图的对流层延迟可能非常大，高达 30 厘米（约 10 条条纹）。当对所有三年的 Sentinel-1 InSAR 观测应用对流层校正时，整体精度水平提高了 13% 至 3.4 厘米。尽管我们的研究集中在大沼泽地，但其在 Sentinel-1 观测对湿地天基水文监测的适用性和得出的精度水平方面的影响适用于位于世界各地的其他具有相似植被类型的湿地。