全球FLUXNET站点总初级生产力的年际变化及其主导因子解析

基于耶鲁互动生物圈模式（YIBs），结合FLUXNET网络观测时间超过8 a的站点的观测数据，研究对不同气象因子影响下总初级生产力（Gross Primary Productivity，GPP）的年际变化进行分析，探讨各植被类型GPP年际变化的主要驱动因子。结果表明，光合有效辐射的变化是落叶阔叶林和常绿针叶林站点GPP年际变化的主要驱动因子，贡献了这些森林类型年际变率的80%。相对湿度变化是作物站点GPP年际变化的主要驱动因子，贡献了作物GPP年际变率的65%。温度是灌木丛站点GPP年际变率的重要因子，其贡献率达到58%。草原站点GPP年际变化的不确定性较大，没有统一的主导因子。研究结果表明，气象要素是全球陆地GPP年际变化的主导因素。在未来气候变化背景下，极端气候事件频发可能会进一步增加GPP的年际变率。

Interannual variability of gross primary productivity at global FLUXNET sites and its driving factors

In this study,using the Yale Interactive Biosphere(YIBs) model,as well as the data from the FLUXNET sites with measurement records longer than 8 years,examines the impacts of multiple meteorological variables on the interannual variability of gross primary productivity(GPP),and identifies the dominant drivers of GPP variability for different plant functional types.The results showed that the change in photosynthetically active radiation is the main driving factor of GPP interannual variability for deciduous broadleaf forests and evergreen needleleaf forests,contributing 80% of the variability for these forest types.In addition,the change in relative humidity is the main driving factor of the GPP interannual variability for cropland,contributing 65% of its GPP variability.Temperature is an important factor for shrubland,its contribution rate is 58%.The GPP interannual variability of grassland shows great uncertainties among sites without uniform driving factors.Our results reveal that meteorological variables are the dominant drivers for the interannual variability of global terrestrial GPP.With the progression of future climate change,more frequent climate extremes may further increase the GPP interannual variability.