基于MODIS的大别山区NPP及NDVI时空动态及相关性研究
Study on Spatiotemporal Dynamics and Correlation of NPP and NDVI in Dabie Mountain Area Based on MODIS
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摘要: 利用2000—2019年MOD13Q1 NDVI和MOD17A3 NPP遥感数据, 在GIS空间分析技术支持下, 利用相关分析、回归分析等方法, 分析了该时段内大别山区归一化植被指数NDVI(Normalized Difference Vegetation Index)与植被净初级生产力NPP(Net Primary Productivity)的时空变化特征, 探讨了该区NPP与NDVI之间的相关性。研究结果表明: ①近20年来大别山区NDVI变化于0.73~0.81, 多年均值为0.78, 空间分布上呈现出由中心向四周边缘递减的趋势, 大别山区在研究时段内植被NDVI呈现出波动上升的趋势, 78.88%的大别山区植被处于改善趋势。②NPP均值为497 g/(m2·a), 变化于402~576 g/(m2·a), 整体上呈现出“中间高、边缘低”的空间分布特征。自2000年以来, 大部分区域的NPP都呈增加的趋势。③NPP与NDVI在时间变化上呈显著正相关, 空间分布上绝大部分区域呈正相关, 但不同植被类型上相关系数有所差别, 其中针叶林的最高, 其次为阔叶林、灌丛和草丛, 栽培植被最低。Abstract: Based on MODIS satellite remote sensing data of MOD13Q1 NDVI and MOD17A3 NPP from 2000 to 2019, and supported by GIS spatial analysis technology, the temporal and spatial variations of the Normalized Difference Vegetation Index (NDVI) and Net Primary Productivity (NPP) in the Dabie Mountain area during the same period are analyzed comprehensively, and the correlation analysis and regression analysis are employed to investigate vegetation dynamics in the Dabie Mountain area during the period of interest. The findings indicate that: ① In the past two decades, NDVI has exhibited a variation range of 0.73~0.81 and an annual average of 0.78. The spatial distribution of NDVI displays a decreasing trend from the center to the periphery, while also exhibiting fluctuating upward trends between 2000 and 2019. During this period, approximately 78.88% of NDVI values exhibited improvement. ② NPP ranges on 402~576 g/(m2·a) with an average value of 497 g/(m2·a), displaying a spatial distribution characteristic of "high values in central regions and lower values at edges". NPP has exhibited an increase in most regions since 2000. ③ There is a significant positive correlation observed between NPP and NDVI. This relationship is found to be positive across most regions, although the strength of correlation varied among different vegetation types. Coniferous forests exhibit the highest correlation coefficient, followed by the broadleaf forests, shrublands and grasslands, while the cultivated vegetation shows the lowest correlation.