Spatio-temporal Dynamics of Vegetation Net Primary Productivity and Driving Mechanism in Urban Agglomeration in Central Yunnan

This study uses trend analysis based on MOD17A3HGF data for the Central Yunnan Urban Agglomeration from 2000 to 2020 to reveal the characteristics and patterns of NPP variation within the region.The driving mechanisms behind these dynamic changes were also examined by analyzing climatic, topographic, and anthropogenic factors. The results indicate that: temporally, the average annual vegetation NPP from 2000 to 2020 was 861.26 g C·m^-2·a^-1, showing an increasing trend at a rate of 4.33 g C·m^-2·a^-1; spatially, NPP values were generally higher in the southwestern part and lower in the northeastern part, with high-value areas concentrated in the central-western and southwestern regions, and low-value areas mainly distributed in the northern and northeastern regions. Among the driving factors, annual precipitation and population density consistently exhibited the strongest explanatory power, while annual mean temperature and slope aspect had the weakest driving effects. All factor interactions showed either two-factor enhancement or nonlinear enhancement, with particularly notable synergistic effects between land use and climatic factors such as precipitation and humidity.