关键词: 净初级生产力, 协同应用, 参数优化, BEPS模型, 总初级生产力

Abstract: Vegetation coverage of Shaanxi Province has been gradually increased since 1999 due to the implementation of largescale ecological construction and protection projects such as returning farmland to forest and grazing prohibition. To provide basis for ecological constructions and planning, we analyzed the spatiotemporal variations of vegetation coverage from 2000 to 2017 in Shaanxi using pixel dichotomy method and its response to climate change through spatial interpolation method, spatial correlation analysis and statistical methods based on MOD13Q1 data and meteorological data. The results showed that vegetation coverage in Shaanxi presented a fluctuational increase during 2000 to 2017 and peaked in 2012. The area with increased vegetation coverage and that with decreased coverage accounted for 82.4% and 17.6% of the total land area, respectively. The vegetation coverage in Northern Shaanxi increased obviously, while there was a decreasing trend in some areas when it reached the maximum value. The regions with large coefficient of variation of vegetation coverage mainly spread over the windblown and sandy areas, hilly and gully regions and surrounding cities along the Great Wall of Northern Shaanxi. There was no positive correlation between vegetation coverage and precipitation or air temperature in Shaanxi on an annual scale. The multiple correlation space between vegetation coverage and precipitation and temperature in the areas which accounted for 98.4% of the whole province failed to pass the 0.05 significance test. Our results indicated that ecological construction projects such as returning farmland to forest play an important role in promoting vegetation restoration and growth, and to a certain extent, reducing the sensitivity of vegetation growth to climatic factors. In the future, there will be a decreasing trend of the vegetation coverage in Shaanxi with the resources and environment constrains of ecological construction projects, and the expansion of urban land use. How to slow down such decreasing trend is an important issue for ecological construction and protection in Shaanxi Province.

Key words: parameter optimization, collaborative application, BEPS, gross primary productivity, net primary productivity.