环境一号卫星与 MODIS NDVI 的定量关系分析

摘要

不同遥感器由于波段设置和光谱响应函数差异导致其在红光和近红外波段所接收的地物反射信号不同，产生了 NDVI 的不一致性问题，针对这一问题，该文研究了 HJ-1 NDVI 和 MODIS NDVI 的定量关系。采用高光谱 Hyperion 数据进行光谱卷积和空间卷积，模拟 HJ-1与 MODIS 两遥感器波段反射率数据。通过计算 NDVI，进行回归分析求出两者之间的定量关系。分别基于单一覆盖类型和混合覆盖类型建立 HJ-1与 MODIS 的转换方程，排除其定量关系可能受不同土地覆盖类型的影响。定量分析与精度验证表明：HJ-1 NDVI 与 MODIS NDVI有很高的线性正相关性（R 2＞0．99）；单一覆盖类型转换精度高于混合覆盖类型转换精度，均能满足定量应用要求，但单一覆盖类型转换在实际应用中较为复杂，可采用混合覆盖类型转换方程进行 HJ-1 NDVI 与 MODIS NDVI 的转换。%Quantitative relationship between NDVI of HJ-1 and MODIS was acquired using Hyperion hyperspectral data. Hyperion scenes were processed to simulate NDVI of the two sensors.To study the effect of land cover on the relationship of NDVI of HJ-1 and MODIS,regression models were derived both for land cover-dependent and land cover-independent situation. The conversion models were directly validated by comparison of HJ-1 and MODIS image data.The result indicated that HJ-1 NDVI was highly correlated with MODIS NDVI (R2 >0.99);Regression models under both situations worked well.The land cover-dependent model worked slightly better than the land cover-independent,but it was more complicated when used.So it was suggested to use a single equation to convert HJ-1 NDVI to MODIS NDVI.