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干旱是一种频繁发生的自然灾害,遥感监测干旱已成为重要的研究方向。可从农田遥感干旱监测最主要的两种地物类型(植被和土壤)的光谱特性分析入手,选择了对水分变化敏感的红光、短波红外波段来监测干旱状况,以短波红外与红光的差值和短波红外与红光的和构建新的光谱空间特征,提出了干旱监测的新方法——归一化的干旱监测指数NPDI。用野外实测的土壤含水量对NPDI模型进行验证,结果表明:NPDI,MPDI与10cm处的土壤含水量模型都具有较高的相关性,其R2分别为0.583和0.438,NPDI模型的监测效果要优于MPDI。此模型是对PDI,MPDI和SPSI等模型的进一步改进,可实现对不同植被覆盖度的、整个生长季的农田干旱监测,在实际的农田干旱监测中具有较高的应用潜力和推广价值。
Drought is a kind of frequent natural disasters. Remote monitoring of drought has become an important research direction. Based on the analysis of the spectral characteristics of the two main types of vegetation (soil and vegetation) of remote sensing and drought monitoring in farmlands, the authors selected the red and shortwave infrared bands that are sensitive to water changes to monitor the drought conditions. The shortwave infrared and red light Difference and sum of shortwave infrared and red light, a new method of drought monitoring - normalized drought monitoring index NPDI was proposed. NPDI model was validated by field measured soil moisture. The results showed that NPDI and MPDI had a high correlation with soil moisture at 10cm, with R2 of 0.583 and 0.438, respectively. The NPDI model had better monitoring results At MPDI. This model is a further improvement of the model such as PDI, MPDI and SPSI. It can monitor the farmland drought with different vegetation coverage throughout the growing season, and has high potential and extension value in the actual farmland drought monitoring.