Fine-Scale Evaluation of Carbon Exchange Capacity in Terrestrial Ecosystems of China: Leveraging Flux Data From Meteorological Stations for Enhanced Database Representation

Over the past two decades, China has experienced frequent extreme events and substantial land cover changes. Site-scale assessments of net ecosystem exchange (NEE) are constrained by the fixed land cover types at eddy covariance towers and short observation periods at existing sites. Using the Eurasian Meteorological Stations Net Ecosystem Exchange product (EAM-NEE), this study evaluated China's carbon exchange dynamics from 2003 to 2018. Results show that southwestern forests exhibit the highest annual carbon sink capacity, while the establishment of national forest parks has contributed positively to enhancing the carbon sink capacity of northern forests. Substantial uncertainties in NEE evaluation were observed, largely due to variations in scales and thresholds. Our findings highlight the importance of site-scale assessments in evaluating the carbon sink capacity and informing targeted strategies for China's dual-carbon goals. Despite limitations in regional representation, the EAM-NEE product provides valuable insights for localized assessments.