长江流域陆地植被总初级生产力时空变化特征及其气候驱动因子

长江流域是我国重要的工农业生产区和生态安全屏障。深入开展长江流域陆地植被总初级生产力（GPP）时空变化特征和驱动因子研究，对了解变化环境下区域植被生长状况和生物固碳能力、掌握生态环境质量具有重要意义。基于MODIS GPP遥感数据产品、土地利用和气象观测数据，采用趋势分析和偏相关分析法，系统研究了2000-2015年间长江流域陆地植被GPP时空变化特征，探讨了不同二级水资源区内气候因子对GPP变化影响的空间差异，揭示了不同土地利用类型GPP变化特征以及气候因子作用。结果表明：1）长江流域陆地植被覆盖区GPP在0.3-2765 gC m^-2 a^-1之间，均值约990.46 gC m^-2 a^-1，多年平均GPP总量为1.735 P gC；2）近年来，长江流域GPP呈不显著上升趋势，趋势率为2.39 gC m^-2 a^-1。空间上，GPP上升区和下降区分别占总流域面积的68%和32%。各二级水资源区内，除了洞庭湖流域和太湖流域GPP呈下降趋势外，其他区GPP均呈上升趋势；3）不同土地利用类型GPP均值在198.50-1276.90 gC m^-2 a^-1之间。各土地利用类型中除水田GPP呈微弱下降外，其他均呈上升趋势，尤其是高、中、低覆盖度草地GPP上升趋势较为显著；4）不同气候因子对植被GPP变化的影响程度在不同二级水资源区、不同土地利用类型间均存在一定差异，但就长江流域整体而言，GPP年际变化受温度影响显著，其次是蒸发，而降水等其他气候因子的影响不大。

Spatio-temporal variations of land vegetation gross primary production in the Yangtze River Basin and correlation with meteorological factors

The Yangtze River Basin is an important industrial and agricultural production area and ecological security barrier in China. Investigation of the spatio-temporal variations and driving factors of terrestrial vegetation gross primary production (GPP) is essential for understanding of vegetation growth and carbon sequestration capacity, grasping the quality of eco-environment and promoting the utilization of ecological resources. Based on MODIS GPP products, land use data and meteorological observations, the current study systematically examined the spatio-temporal variations of land vegetation GPP in the Yangtze River Basin during 2000-2015 by the application of trend analysis and partial correlation analysis. In addition, from the perspective of secondary water resource regionalization, the spatial differences of the impacts of meteorological factors on GPP change were investigated, and the characteristics of GPP change of different land use types and the effects of meteorological factors were revealed. Results showed that:1) the vegetation GPP per unit area in the Yangtze River Basin ranged from 0.3 to 2765 gC m^-2 a^-1, with an average value of 990.46 gC m^-2 a^-1, and the annual mean total GPP of the basin was 1.735 P gC. 2) The GPP of the Yangtze River Basin showed an increasing trend but not significant in recent years with a linear change rate of 2.39 gC m^-2 a^-1. Spatially, the increasing and decreasing areas of GPP account for 68% and 32% of the total watershed area, respectively. In each secondary water resources area, except for the Dongting Lake Basin and Taihu Lake Basin, the GPP in other areas showed an increasing trend. 3) The average GPP of different land use types ranged from 198.50 to 1276.90 gC m^-2 a^-1. Except for paddy field, GPP of the other land use types showed an increasing trend, especially for grassland with high, medium and low coverage. 4) The impact of different meteorological factors on GPP changes varied obviously in different secondary water resources areas and in different land use types. However, annual variation of GPP for the whole Yangtze River Basin was significantly affected by temperature, followed by evaporation, while other meteorological factors have little influence.