基于光谱与光合参量的油菜叶片总初级生产力反演

Inversion of Rape Leaves Gross Primary Productivity Using Spectral & Photosynthetic Parameters

以“华油杂9号”油菜光谱反射率和光合参量数据为数据源,使用8种植被指数,分别建立VI、PAR_(in)×VI及PAR_(in)×VI×Cond 3类总初级生产力(gross primary productivity,GPP)反演模型,并验证精度,结果表明:(1)光合有效辐射和叶片气孔导度是影响油菜光合作用的重要因素,不考虑其影响仅使用植被指数反演油菜GPP效果不佳,模型R~2均低于0.5。(2)结合入射光合有效辐射和叶片气孔导度两个光合参量构建的反演模型PAR_(in)×VI×Cond效果良好,模型平均R~2高于0.89,平均RMSE(root mean squares error)不超过2.17 g·m^(-2),效果最佳的MTCI模型,其平均拟合优度R~2可达0.91,RMSE为1.90 g·m^(-2),满足反演油菜叶片GPP精度要求。因此,基于光谱和光合参量的模型可以用于油菜叶片总初级生产力反演。

Based on “Huayouza9” rape leaf spectral reflectance and photosynthetic parameters data as data sources,8 vegetation index are used to establishe VI,PAR_(in)×VI,PA-R_(in)×VI×Cond three kinds of GPP inversion models respectively,and the accuracy is verified.The results show that(1)PAR and Cond is the important factors influencing the rape photosynthesis,estimating GPP based only on vegetation index was infeasible with model R2 below 0.5.(2)the inversion model PAR_(in)×VI×Cond constructed by combining PAR and Cond has good effect.Model R~2 is higher than 0.89 and RMSE is no more than 2.17 g·m^(-2).The MTCI model with R~2 of 0.91 and RMSE of 1.90 g·m^(-2) is the best effect,which meets the requirements of estimation accuracy of rape leaves GPP.Therefore,the model based on spectral and photosynthetic parameters can be used for the inversion of GPP of rape leaves.