NOAA/AVHRR与EOS/MODIS遥感产品NDVI序列的对比及其校正

Contrast and Calibration of Remote Sensing Production NDVI of NOAA/AVHRR and EOS/MODIS

利用Terra、Aqua两颗卫星的MODIS资料、NOAA-16和17的AVHRR资料,通过对太阳和卫星天顶角及方位角等引起的大气效应订正、大气气溶胶等粒子的散射订正以及NOAA系列卫星信号的衰减订正,得到以上四颗卫星一系列的NDVI产品;对比分析了上午星Terra和NOAA-17,下午星Aqua和NOAA-16两组不同卫星传感器NDVI的差异及其与光谱响应函数的关系。结果表明,Terra和Aqua卫星NDVI随卫星观测角度的不同差异较大,平均NDVI是一种更适合的MODIS/NDVI产品算法,它代表了观测角为±30°之间的NDVI值的分布,在大气和角度的订正基础上,本研究采用了三阶多项式再次订正了观测角引起的NDVI变化;NOAA-16和17所获得的NDVI值较MODIS得到的NDVI值小很多,以MODIS的NDVI产品为标准,应用光谱响应函数将NOAA系列NDVI进行归一化处理,所得的结果基本与MODIS所得的NDVI相当;该方法基本能实现NDVI产品序列的延伸,其资料序列有时空可比性。

Using the MODIS data of Terra and Aqua satellites,AVHRR data of NOAA-16 and NOAA-17,data calibration are done in allusion to influence of zenith and azimuth angle of sun and sensors,scatter of aerosol particle,and attenuation of sensor on NOAA satellites.By calibration,some NDVI values are gained,NDVI of Terra and NOAA-17,NDVI of Aqua and NOAA-16 are analyzed,the relations of NDVI with spectral response function are also analyzed.The results show that NDVI from Terra and Aqua change with observing angles,average NDVI is a perfect composite arithmetic,which represent NDVI within ±30° angle.Angle calibration of NDVI is done again.NDVI from NOAA-16 and NOAA-17 are less than it from MODIS,referred to MODIS NDVI,the NDVI from NOAA is normalized according to spectral response functions,normalized NDVI is very closed to NDVI from MODIS,which means that it is a perfect method to continue NDVI production.