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

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。

Analysis on Relationship Between Net Primary Productivity and Evapo-transpiration Based on MODIS Data in Shaanxi Province

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.