综述了基于遥感光谱信息的植被水分信号提取的研究进展， 包括直接利用光谱反射率反演植被水分信息到建立植被水分指数(WI)， 再发展至利用辐射传输模型来获取植被冠层水分信息。 着重评述了针对低植被覆盖条件下的提取其冠层水分信息的方法， 包括利用冠层生理参数估算植被水分信号； 基于去除土壤背景影响的光谱植被水分指数或辐射传输模型估算植被水分信息， 以及基于多角度的星-地观测提取稀疏条件下的植被水分信息。 最后讨论了针对提取低覆盖植被冠层水分信息方法的可能发展趋势。

The present paper reviews the progress in the methods of retrieving vegetation water content using remote sensing spectral information, including vegetation spectral reflectance information (VIR, SWIR, and NIR) to directly extract vegetation water content and establish vegetation water indices (WI), i.e. NDWI=(R860-R1 240)/(R860+R1 240) and PWI=R970/R900; and using radiation transfer (RT) model such as PROSPAIL to detect plant water content information. The authors analyze the method of retrieving vegetation water content under low crop coverage condition. The plant water can be estimated by using canopy physiological parameters firstly, and using vegetation indices and radiation transfer model secondly, which can eliminate soil background effect. The estimated agricultural drought and vegetation water content by using multi-angle polarized reflectance and bi-directional reflectance (BRDF) was discussed in this paper. In the end, the possible development trend of retrieval methods for plant water information under plant low coverage conditions was discussed.