HJ-1ACCD与TM数据及其估算草地LAI和鲜生物量效果比较分析

Comparison of HJ-1A CCD and TM data and for estimating grass LAI and fresh biomass

基于地面实测和PROSAIL模型模拟数据,研究了新型传感器HJ-1ACCD与TM数据一致性问题,分析了传感器天顶角和光谱相应函数差异的影响,对比两种传感器数据估算草地LAI和鲜生物量的效果,得出以下结论:(1)HJ-1ACCD和TM反射率数据的拟合系数R2在0.7322和0.9205左右,在反射率较小时,两种传感器数据一致性较好;随着反射率增大,HJ-1ACCD数值逐渐高于TM。总体而言,在可见光和近红外波段,两种传感器较为接近,其中红波段最接近。(2)两种传感器的NDVI数据一致性非常高,且受传感器天顶角和光谱响应函数影响作用较小(相对误差约为0.34%—0.53%),而反射率的相对差别在3.34%—9.54%。(3)传感器天顶角较光谱响应函数对反射率影响更大。(4)基于HJ-1ACCD反射率数据估算草地LAI和鲜生物量效果较好,其中以CCD2传感器估算效果最好。

Based on field measurements and the PROSAIL model simulations, this paper compared the new HJ-1A CCDs sensors data and the widely used TM data, and analyzed the effects of the sensors zenith angle and spectral response function （SRF）. We further compared the two sensors in estimating grass LAI and fresh biomass. The following conclusions can be drawn： （1） the adjusted coefficients of determination R： between HJ-1A CCDs and TM reflectance ranged from 0.7322 to 0.9205. The reflectance of the two sensors are very consistent while the absolute value is small, but as the grass cover faction increases, HJ- 1A CCDs data is a little larger than TM. Overall, for the visible and near infrared bands, the HJ-1A CCDs image data is generally similar to the TM data. For HJ-1A CCDs and TM, the reflectance in red band showed the best correlation. （2） The normalized difference vegetation index （NDVI） of HJ-1A CCDs and TM are significantly correlated. Compared with reflectance data （with relative difference of 3.34%-9.54%）, NDVI is less affected （with relative difference of 0.34%-0.53%） by sensor zenith angle or spectral response function. （3） The sensor zenith angle was proved making a slightly greater impact on the sensor reflectance data than the spectral response function. （4） HJ-1A CCDs reflectance data exhibited good correlations with grass LAI and fresh biomass, and H J-1A CCD2 data performed the best.