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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 the field measurements and the PROSAIL model simulation data, the consistency between the new sensor HJ-1ACCD and the TM data was studied. The influence of the difference between the sensor zenith angle and the corresponding spectral function was analyzed. The LAI and fresh biomass of the grassland were estimated by comparing the two sensor data The results show that: (1) The fitting coefficients R2 of HJ-1ACCD and TM reflectance data are about 0.7322 and 0.9205, respectively. When the reflectance is small, the data consistency of the two sensors is good. With the increase of reflectance , HJ-1ACCD values gradually higher than the TM. Overall, the two sensors are closer in the visible and near infrared bands, with the closest red band. (2) The consistency of the NDVI data of the two sensors is very high, and is less affected by the sensor zenith angle and the spectral response function (relative error is about 0.34% -0.53%), while the relative difference of reflectivity is 3.34% 9.54%. (3) The sensor zenith angle has a greater effect on reflectance than the spectral response function. (4) The estimation of LAI and fresh biomass of grassland is better based on the HJ-1ACCD reflectance data, of which CCD2 sensor is the best.