基于近地高光谱棉花生物量遥感估算模型

分析棉花地上鲜生物量冠层高光谱反射率变异系数，反射率光谱、一阶微分光谱与地上鲜生物量相关关系得结果表明：在可见光近红外波段棉花冠层反射率光谱变异系数在672 nm波段处最大；棉花地上鲜生物量与反射率光谱相关系数最大值在可见光波段出现在589~700 nm，在近红外波段出现在865~919 nm波段，且前者大于后者。地上鲜生物量与一阶微分光谱相关系数在可见光波段出现524~528 nm、552~588 nm、710~755 nm 3个高值区。基于以上研究，选择19个高光谱特征参数建立了棉花地上鲜生物量高光谱遥感监测模型，经检验，单波段中以F₆₂₉估算水平最高，估算模型为Y = 9.7914 exp(－20.738 F629)，准确度为83.9%、RMSE为0.64 kg m^-2、预测值与实测值相关系数为0.940**；组合参数以[629, 901]指数形式估算模型估算水平最高，模型为Y = 0.0986 exp(4.3696[629, 901])，准确度达84.0%，RMSE为0.55 kg m^-2，预测值与实测值相关系数为0.960**，上述两个模型为参选模型中估算棉花地上鲜生物量最佳高光谱估算模型。

Estimation Models of Cotton Aboveground Fresh Biomass Based on Field Hyperspectral Remote Sensing

Aboveground fresh biomass is an important colony qualitative index of cotton,and so it is important for production management and yield estimation in cotton to establish the monitoring model based on hyperspectral parameter.The wavelength variation coefficient of cotton canopy hyperspectrum on aboveground fresh biomass and the correlation between the aboveground fresh biomass and reflective spectrum,the first derivative spectrum showed that the biggest value of hyperspectral variation coefficient of cotton canopy reflectance in the visible light region was in 672 nm.The biggest value of correlation coefficient between the aboveground fresh biomass and reflectance spectrum at the visible light region was in 589700 nm and at the near infrared red region in 865919 nm,and the former was larger than latter.The correlation coefficient between the aboveground fresh biomass and the first derivative value in the visible light had three high-value areas including 524528 nm,552588 nm and 710755 nm.According to the analysis above,the nineteen hyperspectral characteristic parameters were used to establish the hyperspectral remote sensing estimation models of the aboveground fresh biomass in cotton.The tested result of models expressed the parameters veracity of estimating the aboveground fresh biomass in cotton,including reflectance of 682 nm and 629 nm and the combination forms,was up 80%.Among them,F629[Y = 9.7914 exp(-20.738 F629)] in single band reflectance parameters was better,its veracity reached to 83.9%, RMSE was 0.64 kg m-2,and the correlation coefficient between the estimated value and measured value was 0.94**;The monitoring model of [629,901] [Y = 0.0986 exp(4.3696 [629,901])] was best,and its veracity reached to 84.0%,RMSE was 0.55 kg m-2,and the correlation coefficient between the estimated value and measured value was 0.96**,the two models above were the best among the elected models estimating cotton aboveground fresh biomass.