基于MODIS数据的陕西省植被净初级生产力与实际蒸散的变化关系分析

Analysis on Relationship Between Net Primary Productivity and Evapotranspiration Based on MODIS Data in Shaanxi Province

[目的]分析陕西省植被净初级生产力(NPP)及实际蒸散量(ET),为生态环境中碳循环、水循环特征提供理论支持。[方法]基于美国航天局(NASA)提供的净初级生产力产品(MOD17A3)及蒸散产品(MOD16)数据,利用GIS与数理统计等方法,对陕西省2000—2014年植被NPP与ET的时空分布特征及其关系进行分析。[结果]陕西省植被NPP与ET的分布特征均为南高北低;2000—2014年陕西省植被NPP在波动中呈现上升趋势,其中陕北地区增加最大,陕南地区增加最不显著;陕西省ET年际变化呈波动状态。植被NPP与ET空间相关性较显著,陕北地区相关系数极高,而陕南地区相关性并不显著。[结论]在较为干旱区域植被NPP与ET的关系更为密切。

[Objective] Analyzing the vegetation net primary productivity（NPP） and the actual evapotranspiration（ET） in Shaanxi Province, to provide theoretical support with regard to carbon cycle, water cycle characteristics of ecological environment.[Methods] Based on data of the NASA products of net primary productivity（MOD17 A3） and evapotranspiration（MOD16）, the spatial and temporal variation characteristics and relationships between NPP and ET in 2000-2014 of Shaanxi Province were analyzed by using the methods of GIS and mathematical statistics.[Results] The vegetation NPP and ET both showed a spatial distribution characteristics by gradually decreasing from the south to the north. In 2000-2014, interannual variability of Shaanxi vegetation NPP presented an increasing trend. The most significant increased region was Shanbei, the second was Guanzhong, and the lowest region was Southern Shaanxi; interannual variability of ET was not significant, and showed a trend of fluctuations. Spatial correlation between NPP and ET was significant for overall province, but regional difference existed：correlation coefficient in Shanbei region was highly significant, whereas in the southern Shaanxi region, it was not significant.[Conclusion] The vegetation NPP had closer relations with ET in arid area.