Rapid Flood Progress Monitoring in Cropland with NASA SMAP
Rapid Flood Progress Monitoring in Cropland with NASA SMAP
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DOI：
10.3390/rs11020191
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
M. S. Rahman;L. Di;E. Yu;Li Lin;Chen Zhang;Junmei Tang
中科院分区：
文献类型：
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作者：
M. S. Rahman;L. Di;E. Yu;Li Lin;Chen Zhang;Junmei Tang
不同农业部门的研究，包括洪水期间的作物损失估计和产量估计，在很大程度上依赖于淹没信息。星载遥感已广泛应用于洪水测绘和监测。然而，光学遥感无法穿透云层，以及高时间分辨率的合成孔径雷达数据的匮乏，在很多情况下阻碍了洪水制图的应用。土壤水分主动被动(SMAP)4级产品是来自SMAP观测的模型驱动的土壤水分数据，可以每隔3小时获得一次，可以提供一个中间但有效的解决方案。这项研究通过结合SMAP地表土壤水分、土壤物理性质和国家洪泛区信息绘制了农田洪水进程图。土壤有效孔隙度以上的土壤湿度是土壤饱和度的直接指示。在洪水期间，土壤水分也会显著增加。因此，该方法考虑了三个条件来绘制淹没像元：从洪水前到洪水后，土壤水分至少增加0.05M3M−3，土壤水分高于有效土壤孔隙度，以及连续72小时保持饱和状态。结果表明，在大多数情况下，SMAP导出的地图能够成功地绘制参考地图中的大部分洪涝区域，尽管存在一定程度的高估(由于SMAP的空间分辨率较低)。最后，利用联邦紧急事务管理署(FEMA)的空间危险带区域(SHFA)和农田数据层(CDL)从饱和区域中提取淹没的农田。从SMAP数据提取的洪水图与联邦应急管理局宣布的受影响县以及其他来源的洪水图进行了验证。
Research in different agricultural sectors, including in crop loss estimation during flood and yield estimation, substantially rely on inundation information. Spaceborne remote sensing has widely been used in the mapping and monitoring of floods. However, the inability of optical remote sensing to cloud penetration and the scarcity of fine temporal resolution SAR data hinder the application of flood mapping in many cases. Soil Moisture Active Passive (SMAP) level 4 products, which are model-driven soil moisture data derived from SMAP observations and are available at 3-h intervals, can offer an intermediate but effective solution. This study maps flood progress in croplands by incorporating SMAP surface soil moisture, soil physical properties, and national floodplain information. Soil moisture above the effective soil porosity is a direct indication of soil saturation. Soil moisture also increases considerably during a flood event. Therefore, this approach took into account three conditions to map the flooded pixels: a minimum of 0.05 m3m−3 increment in soil moisture from pre-flood to post-flood condition, soil moisture above the effective soil porosity, and the holding of saturation condition for the 72 consecutive hours. Results indicated that the SMAP-derived maps were able to successfully map most of the flooded areas in the reference maps in the majority of the cases, though with some degree of overestimation (due to the coarse spatial resolution of SMAP). Finally, the inundated croplands are extracted from saturated areas by Spatial Hazard Zone areas (SHFA) of Federal Emergency Management Agency (FEMA) and cropland data layer (CDL). The flood maps extracted from SMAP data are validated with FEMA-declared affected counties as well as with flood maps from other sources.