[A-CG35] Global Carbon Cycle Observation and Analysis

[ACG35-03] A comprehensive assessment of VISIT GPP using the different GPP products and site-level FLUXNET database

*Ruci Wang¹, Kazuhito Ichii¹ (1.Center for Environmrntal Remote Sensing, Chiba University)

Keywords:Terrestrial carbon cycle, Gross primary production (GPP), VISIT model, FLUXNET data

The strength of terrestrial carbon sinks significantly correlates with the gross primary production (GPP) of terrestrial ecosystems, thus garnering considerable attention in recent years. GPP is a pivotal element within the carbon biogeochemical cycle, establishing a connection between atmospheric CO2 and terrestrial ecosystems. Accurate quantification of GPP at regional and global scales is paramount for carbon budgets and climate change studies. This study initially computed gross primary productivity (GPP) utilizing a terrestrial carbon cycle model, the Vegetation Integrative SImulator for Trace gases (VISIT). Subsequently, we assessed and compared more than ten GPP datasets across various spatiotemporal scales. Moreover, the FLUXNET2015, ICOS Drought 2018, and ICOS Warm Winter 2020 datasets have been chosen as the site-specific databases for cross-validating GPP. The findings indicate variations in GPP results across different land cover types among the various GPP products. It is acknowledged that the GPP models are heavily influenced by various climatic factors such as temperatures, precipitation, and photosynthetically active radiation. These factors can significantly impact the uncertainties, errors, and accuracies of the models. Moreover, remote sensing data is susceptible to the influence of cloudiness and aerosols, necessitating further efforts to enhance data quality. This study offers valuable insights that can guide future enhancements and applications of the terrestrial GPP models.