Assessment of the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) as an Agricultural Drought Index in China
Assessment of the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) as an Agricultural Drought Index in China
复制标题
SMAP 衍生土壤水分亏缺指数（SWDI-SMAP）作为中国农业干旱指数的评估
DOI：
10.3390/rs10081302
复制
发表时间：
2018-08-01
期刊：
影响因子：
5
通讯作者：
Cai, Yang
中科院分区：
文献类型：
--
作者：
Bai, Jueying;Cui, Qian;Cai, Yang
中国是一个干旱灾害频发的地区，干旱监测是一项重要的工作。基于土壤有效含水量的干旱评价可以直接反映土壤水分亏缺状况。微波遥感技术使全球SM的估计具有很高的时间分辨率。目前，土壤水分主被动（SMAP）SM产品的评价还不充分，L波段微波数据还没有应用于全国各地的农业干旱监测。首先利用中国各地的实测数据对SMAP L3辐射计反演的SM产品进行了关键性评价，以辅助后续的干旱评估，然后将SMAP-SMAP反演的土壤水分亏缺指数（SWDI-SMAP）与大气水分亏缺指数（AWD）和植被健康指数（VHI）进行了比较。结果表明，SMAP能以较高的精度获得SM，SWDI-SMAP在干旱监测中具有较好的综合性能。SWDI-SMAP的表现相对较好，除了在一些山区; SWDI-SMAP一般表现较好，在北部比在南部少干的偏见，虽然更好的性能SMAP SM的基础上的R显示在南部比在北部; SWDI-SMAP和VHI之间的差异主要表现在没有植被或那些包含耐旱植物的地区。综上所述，SWDI-SMAP在干旱监测中具有很大的应用潜力。
China is frequently subjected to local and regional drought disasters, and thus, drought monitoring is vital. Drought assessments based on available surface soil moisture (SM) can account for soil water deficit directly. Microwave remote sensing techniques enable the estimation of global SM with a high temporal resolution. At present, the evaluation of Soil Moisture Active Passive (SMAP) SM products is inadequate, and L-band microwave data have not been applied to agricultural drought monitoring throughout China. In this study, first, we provide a pivotal evaluation of the SMAP L3 radiometer-derived SM product using in situ observation data throughout China, to assist in subsequent drought assessment, and then the SMAP-Derived Soil Water Deficit Index (SWDI-SMAP) is compared with the atmospheric water deficit (AWD) and vegetation health index (VHI). It is found that the SMAP can obtain SM with relatively high accuracy and the SWDI-SMAP has a good overall performance on drought monitoring. Relatively good performance of SWDI-SMAP is shown, except in some mountain regions; the SWDI-SMAP generally performs better in the north than in the south for less dry bias, although better performance of SMAP SM based on the R is shown in the south than in the north; differences between the SWDI-SMAP and VHI are mainly shown in areas without vegetation or those containing drought-resistant plants. In summary, the SWDI-SMAP shows great application potential in drought monitoring.