Surface Water Monitoring within Cambodia and the Vietnamese Mekong Delta over a Year, with Sentinel-1 SAR Observations
Surface Water Monitoring within Cambodia and the Vietnamese Mekong Delta over a Year, with Sentinel-1 SAR Observations
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DOI：
10.3390/w9060366
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发表时间：
2017-06-01
期刊：
影响因子：
3.4
通讯作者：
Aires, Filipe
中科院分区：
文献类型：
--
作者：
Binh Pham-Duc;Prigent, Catherine;Aires, Filipe
本研究提出了一种利用 Sentinel-1 合成孔径雷达 (SAR) 数据在柬埔寨和越南湄公河三角洲内检测和监测地表水的方法。它基于在 Landsat-8 光学数据上训练的神经网络分类。进行敏感性测试以优化分类性能并评估检索准确性。将预测的 SAR 地表水图与参考 Landsat-8 地表水图进行比较，显示在 30 m 空间分辨率下，真实的水检测率接近 90%。预测的 SAR 地表水图也与从高空间分辨率地形数据导出的可淹性图进行了比较。结果显示，两个独立地图之间具有高度一致性，其中 98% 的 SAR 地表水位于洪水可能性较高的区域。最后，对 2015 年湄公河三角洲所有可用的 Sentinel-1 SAR 观测进行处理，并将得出的地表水图与相应的 MODIS/Terra 得出的 500 m 空间分辨率的地表水图进行比较。这两种产品之间的时间相关性非常高 (99%)，在云污染较低的旱季期间，水面范围非常接近。这项研究强调了 Sentinel-1 SAR 数据对于地表水监测的适用性，特别是在雨季云量可能非常高的热带地区。
This study presents a methodology to detect and monitor surface water with Sentinel-1 Synthetic Aperture Radar (SAR) data within Cambodia and the Vietnamese Mekong Delta. It is based on a neural network classification trained on Landsat-8 optical data. Sensitivity tests are carried out to optimize the performance of the classification and assess the retrieval accuracy. Predicted SAR surface water maps are compared to reference Landsat-8 surface water maps, showing a true positive water detection of approximate to 90% at 30 m spatial resolution. Predicted SAR surface water maps are also compared to floodability maps derived from high spatial resolution topography data. Results show high consistency between the two independent maps with 98% of SAR-derived surface water located in areas with a high probability of inundation. Finally, all available Sentinel-1 SAR observations over the Mekong Delta in 2015 are processed and the derived surface water maps are compared to corresponding MODIS/Terra-derived surface water maps at 500 m spatial resolution. Temporal correlation between these two products is very high (99%) with very close water surface extents during the dry season when cloud contamination is low. This study highlights the applicability of the Sentinel-1 SAR data for surface water monitoring, especially in a tropical region where cloud cover can be very high during the rainy seasons.