基于SCOPE模型的水稻不同生育期日光诱导叶绿素荧光及GPP模拟研究

日光诱导叶绿素荧光(Sun-induced Chlorophyll Fluorescence,SIF)作为监测总初级生产力(Gross Primary Production,GPP)最有效的手段之一,相对于传统的绿度植被指标,能直接反映光合作用的动态变化。SCOPE (Soil Canopy Observation,Photochemistry, and Energy fluxes)模型可以用于同时模拟荧光和GPP,但其在不同生育期和天气条件下的模拟效果仍有待验证。基于2016年水稻生育期的生理参数和气象观测数据,利用冠层SIF76O和GPP的观测值验证了SCOPE模型模拟的不同生育期和天气条件下的SIF76o和GPP。研究结果表明:SCOPE模型可以模拟季节尺度上的SIF76O和GPP(R^2=0.44和R^2=0.67);从日尺度上来看,SCOPE模型在不同生育期有不同的表现,成熟期时SCOPE模型估算的SIF76O和GPP效果最好(R^2=0.99和R^2=0.96),而抽穗一开花期模型的模拟效果最差。从整个生育期来看,SCOPE模型模拟的SIF76O值低于实际观测值,而GPP的模拟值偏高,但整体趋势一致。同时,天气状况也会对SCOPE模型的模拟SIF76O结果产生影响,晴天SCOPE模型模拟的SIF760要优于多云(R^2=0.64和R^2=0.46)。因此,SCOPE模型可以用于模拟水稻在不同生育期的SIF760和GPP。该研究结果为荧光遥感监测农田生态系统生产力以及对其环境因子的响应研究提供了一定的模型基础。

Sun-induced Chlorophyll Fluorescence and GPP Simulations with SCOPE Model for Paddy Rice Under Different Growing Stages

Compared with traditional greenness-based vegetation indicators,Sun-induced Chlorophyll Fluorescence (SIF),as one of the most effective tools in monitoring Gross Primary Production(GPP),can be used to directly reflect the dynamic changes of photosynthesis.The SCOPE (Soil Canopy Observation,Photochemistry,and Energy Fluxes) model has been widely used to simulate the SIF and GPP across multiple scales.However,the accuracy and ability of the SCOPE model on the simulations under different growth stages and weathers remains unclear.In this study,we investigated the performance of SCOPE in SIF76O and GPP based on the physiological parameters and meteorological data of paddy rice in 2016.Then we compared the simulations with the measured SIF76o and GPP under different growing stages and weather conditions.The results showed that the SCOPE model could simulate well for SIF760 and GPP at the seasonal scale (R^2 =0.44 and R^2=0.67).However,the SCOPE model had different performances under different growth stages at the diurnal scale A better performance was obtained in maturity stage of rice (R^2=0.99 and R^2=0.96),while a lower performance was at the heading-flowering stage.During the whole growth period,the SIF760 simulated by the SCOPE model was lower than the measured SIF760 while the simulated GPP was higher.In add让ion,weather conditions significantly affect the simulations from the SCOPE model.The accuracy of the SIF760 simulations on sunny days was better than that in cloudy days (R^2=0.64 and R^2=0.46 respectively).Our quantitative assessment of the SCOPE model supported its usefulness for interpreting SIF and GPP under different growth stages.These results provided the model evidence for remote sensing of SIF to monitor crop photosynthesis and its response on environmental factors.