褶皱山区NDVI与地形因子的多尺度耦合关系研究

Multi-Scale Coupling Relationships between NDVI and Topographic Factors in Folded Mountain Area

【目的】揭示我国长江上游褶皱山区植被分布与地形耦合关系。【方法】基于二维小波分析的方法,分别构建归一化植被指数NDVI和地形因子在不同尺度上的小波低频系数空间分布的特征模式,然后分析NDVI和地形因子小波低频系数的相关性,并建立多尺度下NDVI低频系数的拟合方程。【结果】(1)多尺度下NDVI与高程的空间分布相似度最高;(2)地形因子与NDVI相关性的大小的顺序为高程>坡度>坡向,并随小波分解尺度的增加而增大;(3)小波分解尺度越大,NDVI的最优拟合方程所需的建模因子越多,方程的拟合效果越好。【结论】对揭示多尺度下褶皱山区地形因素对该区域内植被覆盖度高低的影响可提供借鉴,研究结果可为长江上游生态恢复和农业产业规划提供一定的依据。

【Objective】The coupling relationships between vegetation distribution and topography in the folded mountain area of the upper reaches of the Yangtze River in China is revealed.【Method】Wavelet low-frequency coefficients could reflect the global spatial patterns of NDVI and topographic factors.The spatial distributions of low-frequency component were mapped and the regression equation of NDVI were established on the basis of two-dimension wavelet transform.【Result】(1)The spatial patterns of NDVI and elevation had the highest similarity in contrast to other variables.(2)The order of correlations be-tween topographic factors and NDVI was elevation>slope>aspect from 0.5 km to 8 km scales,and the correlation coefficients increased with the multi-scale decomposition.(3)The larger scale decomposition was,the more modeling factors were required for optimal fitting equation of NDVI.【Conclusion】This study can provide a reference for revealing the influence of topographic factors on the vegetation coverage in the folded mountainous area at multiple scales,and the results can provide a certain basis for ecological restoration and agricultural industry planning in the upper reaches of the Yangtze River.