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对模拟中分辨率成像光谱仪 (MODIS)两个植被指数归一化植被指数 (N DV I)、增强植被指数 (EV I)以及红边位置(REP)与水稻叶面积指数 (L AI)进行了相关研究。利用光谱分辨率为 3nm的 ASD F ield Spec U V/VNIR光谱仪获得了2 0 0 2年两个不同水稻品种——杂交稻和常规稻整个生长期的高光谱数据 ,同时对水稻 L AI进行了测定。利用一阶微分计算红边位移。模拟了 MODIS 3个波段 ,波段 1(6 2 0 -6 70 nm ,红波段 ) ,波段 2 (841～ 876 nm ,近红外 )和波段 3(45 9～ 479nm ,蓝波段 ) ,并用这些波段计算了 MODIS-NDVI和 EVI。结果表明 :对于常规稻 ,MODIS-NDVI、EVI和 REP与水稻 L AI呈现出良好的相关性 ;而对于杂交稻 ,与水稻 L AI相关性来说 ,MODIS-EV I和 REP要比 MODIS-NDVI更敏感。分析原因 ,主要是因为杂交稻同常规稻相比在生长的中后期 L A I比较大 ,MODIS-N DVI容易饱和 ;而 MODIS-EVI和 REP由于可以消除背景影响 ,增强对 L AI的敏感性。因此 MODIS-EV I和 REP可以更有效地监测水稻叶面积指数。
Two NDVI, EVI, REP and L AI of simulated mid-resolution imaging spectrometer (MODIS) were studied Related research. Hyperspectral data of two different rice varieties, hybrid rice and conventional rice, were obtained during the whole growth period of 2002 using ASD Field Spec UV / VNIR spectrometer with spectral resolution of 3nm. L AI of rice was also determined . Red Edge Displacement is Calculated Using First Order Derivatives. Three MODIS bands were modeled as 1 (6 2 0-6 70 nm, red band), 2 (841-876 nm, near infrared) and 3 (45 9 ~ 479 nm, blue band) MODIS-NDVI and EVI. The results showed that: MODIS-NDVI, EVI and REP showed good correlation with L AI in conventional rice; while for hybrid rice, the MODIS-EV I and REP were significantly lower than those in MODIS-NDVI More sensitive. The reason for this is mainly due to the fact that the L A I of hybrid rice is larger than that of conventional rice in the middle and late growth stages, and MODIS-N DVI is easy to saturate. However, MODIS-EVI and REP can enhance the sensitivity to L AI by eliminating the background effect. Therefore, MODIS-EV I and REP can monitor rice leaf area index more effectively.