Cheng Xiao-juan, Yang Gui-jun, Xu Xin-gang, Chen Tian-en, Li Zhen-hai, Feng Hai-kuan, Wang Dong
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Dec;34(12):3391-6.
Moisture content is an important indicator for crop water stress condition, timely and effective monitoring crop water content is of great significance for evaluate crop water deficit balance and guide agriculture irrigation. In order to improve the saturated problems of different forms of typical NDWI (Normalized Different Water Index), we tried to introduce EVI (Enhanced Vegetation Index) to build new vegetation water indices (NDWI#) to estimate crop water content. Firstly, PROSAIL model was used to study the saturation sensitivity of NDWI, and NDWI# to canopy water content and LAI (Leaf Area Index). Then, the estimated model and verified model were estimated using the spectral data and moisture data in the field. The result showed that the new indices have significant relationships with canopy water content. In particular, by implementing modified standardized for NDWI1450, NDWI1940, NDWI2500. The result indicated that newly developed indices with visible-infrared and shortwave infrared spectral feature may have greater advantage for estimation winter canopy water content.
含水量是作物水分胁迫状况的重要指标,及时有效地监测作物含水量对于评估作物水分亏缺平衡和指导农业灌溉具有重要意义。为了改善不同形式典型归一化差异水体指数(NDWI)的饱和问题,我们尝试引入增强植被指数(EVI)构建新的植被水分指数(NDWI#)来估算作物含水量。首先,利用PROSAIL模型研究NDWI和NDWI#对冠层含水量和叶面积指数(LAI)的饱和敏感性。然后,利用田间光谱数据和水分数据建立估算模型并进行验证。结果表明,新指数与冠层含水量具有显著关系。特别是,通过对NDWI1450、NDWI1940、NDWI2500实施修正标准化。结果表明,新开发的具有可见-红外和短波红外光谱特征的指数在估算冬季冠层含水量方面可能具有更大优势。