Improving GPP estimates by partitioning green APAR from total APAR in two deciduous forest sites  

作　　者：Siyuan Chen Liangyun Liu Lichun Sui Xinjie Liu 

机构地区：[1]College of Geological Engineering and Geomatics,Chang’an University,Xi’an 710054,People’s Republic of China [2]Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,People’s Republic of China

出　　处：《Journal of Forestry Research》2023年第4期915-927,共13页林业研究（英文版）

基　　金：funded by Innovative Research Program of the International Research Center of Big Data for Sustainable Development Goals(No.CBAS2022IRP01);the National Earth System Science Data Sharing Infrastructure(No.2005DKA32300);the National Natural Science Foundation of China(No.41825002).

摘　　要：Non-photosynthetic components within a forest ecosystem account for a large proportion of the canopy but are not involved in photosynthesis.Therefore,the accuracy of gross primary production(GPP)estimates is expected to improve by removing these components.However,their infl uence in GPP estimations has not been quantitatively evaluated for deciduous forests.Several vegetation indices have been used recently to estimate the fraction of photosynthetically active radiation absorbed by photosynthetic components(FAPAR_(green))for partitioning APAR green(photosynthetically active radiation absorbed by photosynthetic components).In this study,the enhanced vegetation index(EVI)estimated FAPAR_(green)and to separate the photosynthetically active radiation absorbed by photosynthetic components(APAR green)from total APAR observations(APAR_(total))at two deciduous forest sites.The eddy covariance-light use effi ciency(EC-LUE)algorithm was employed to evaluate the infl uence of non-photosynthetic components and to test the performance of APAR green in GPP estimation.The results show that the infl uence of non-photosynthetic components have a seasonal pattern at deciduous forest sites,large diff erences are observed with normalized root mean square error(RMSE*)values of APAR green-based GPP and APAR_(total)-based GPP between tower-based GPP during the early and end stages,while slight diff erences occurred during peak growth seasons.In addition,daily GPP estimation was significantly improved using the APAR green-based method,giving a higher coeffi cient of determination and lower normalized root mean square error against the GPP estimated by the APAR_(total)-based method.The results demonstrate the signifi cance of partitioning APAR green from APAR_(total)for accurate GPP estimation in deciduous forests.

关 键 词：Gross primary production Absorbed photosynthetically active radiation Photosynthetic component Vegetation index AMERIFLUX European fl uxes database 

分 类 号：S718.55[农业科学—林学]