陆地生态系统碳汇评估方法研究进展

“碳中和”是我国作出的一项重大的国家战略决策，陆地生态系统碳汇作为碳增汇的重要组成部分，在碳中和目标实现的过程中发挥着重要的作用。但当前基于不同观测数据和方法的陆地碳汇计算仍有很大的不确定性，为了全面了解陆地生态系统碳汇分布特征，提高陆地生态系统碳汇评估的准确性，梳理了近年来关于陆地生态系统碳汇评估的国内外研究进展，从“自下而上”和“自上而下”两类途径阐述了陆地生态系统碳汇评估的主要方法(样地清查法、涡度相关法、模型模拟法和碳同化反演法)的主要原理和特征，优势和缺陷，及在不同尺度碳汇研究中的应用，并从土地利用/覆盖变化、气候因素(大气CO₂浓度、氮沉降)、环境因素(太阳辐射、温度、降水)等因素阐述了陆地系统碳汇主要驱动因子；分析了我国陆地生态系统碳汇的主要特征及时空变化趋势，并从人类活动(生态工程)和环境因素阐述了中国陆地生态系统碳汇的驱动因素；最后，展望了新的监测手段和评估方法在提升陆地生态系统碳汇评估精度中的作用，从而更好的服务于我国“碳中和”的长远目标。

An overview of terrestrial ecosystem carbon sink assessment methods towards achieving carbon neutrality in China

Terrestrial ecosystem carbon sink is an important component of carbon sink in China, which plays a key role in carbon peaking and carbon neutrality goals achievement. However, there is large uncertainty in estimating terrestrial ecosystem carbon sink due to different types of observation data and assessment methods. To better understand the characteristics of terrestrial ecosystem carbon cycle and improve the accuracy of carbon sink estimation, this review summarized major research progresses in terrestrial carbon sink estimation in China and around the world, and introduced the advantages and disadvantages of major assessment methods (field inventory, eddy covariance method, ecological modelling, and the atmospheric flux inversion method) from bottom-up and top-down ways. Besides, this review clarified major spatial and temporal patterns and change trend, and analyzed the main driving factors of carbon sink from the perspective of land-use/land-cover, climate factors (CO₂ concentration and N deposition), and environmental factors (solar radiation, temperature, and precipitation). Besides, this paper analyzed the main characteristics and temporal and spatial trends of carbon sinks in terrestrial ecosystems in China, and expounded the driving factors of terrestrial ecosystems carbon sinks in China from the perspective of human activities (ecological projects) and environmental factors. On this basis, this review expected the application of new means and methods for improving carbon sink estimation precision and for better serving long-term goal of carbon neutral.