2000-2015年川西地区植被NPP时空动态及驱动因子

对川西植被净初级生产力进行估算并分析了其时空格局变化及驱动因子与植被净初级生产力的变化关系，为深入认识川西植被生产力状况提供科学依据。在原CASA模型的基础上，通过区域实际蒸散量与区域潜在蒸散量对水分胁迫影响系数进行了改进，进而估算2000—2015年期间川西地区植被净初级生产力；运用逐像元趋势法分析了川西地区植被净初级生产力在研究期间内其空间变化情况；同时结合气象因子、土地利用变化、植被类型、地形因素、人类活动与植被净初级生产力进行了相关性分析。结果表明:川西地区植被空间差异明显，其NPP多年平均值为199 gC/（m²·a），在2000—2015年期间，大面积区域植被NPP呈显著上升，汶川、泸定、金川、康定局部区域受自然灾害及人类活动等因素NPP呈下降趋势；降水、气温、太阳辐射等气象因子对植被空间格局分布产生一定影响，不同土地利用及植被类型的NPP差异较大；海拔与研究区NPP相关性非常显著（R²=0.896，p<0.001）；人类活动对汶川、泸定等局部地区负干扰明显。

Temporal and Spatial Dynamics and Driving Factors of Vegetation NPP in Western Sichuan from 2000 to 2015

This study is aimed to estimate the net primary productivity of vegetation in western Sichuan and analyze its spatial-temporal pattern and the relationship between net primary productivity (NPP) of vegetation and its driving factors, which provided a theoretic basis for understanding the status of vegetation productivity in this area. Specifically, the followings were investigated. (1) based on the Original CASA model, the influence coefficient of water stress on regional actual evapotranspiration and potential evapotranspiration was improved, and the NPP of vegetation in western Sichuan from 2000 to 2015 was estimated. (2) A pixel-by-pixel trend method was used to analyze the spatial variation of net primary productivity of vegetation in western Sichuan during the study period. (3) The correlation analysis was conducted between meteorological factors, land use change, vegetation type, topographic factors and human activities and net primary productivity of vegetation. The results showed that the spatial variation of vegetation in western Sichuan was obvious with the average annual NPP of 199 gC/(m²·a); during the period 2000-2015, the NPP of vegetation in large areas increased significantly, while in some areas like Wenchuan, Luding, Jinchuan and Kangding, the values declined due to natural disasters and human activities; the meteorological parameters such as precipitation, temperature and solar radiation hadcertain influence on the spatial pattern of vegetation, causing the difference of NPP in area with different land uses and vegetation types; the correlation between altitude and NPP in the study area was highly significant (R²=0.896,p<0.001) and human activities had a significant negative influence on NPP in the areas such as Wenchuan and Luding.