基于MODIS-NDVI的云南省植被时空变化及驱动因素分析

Spatiotemporal changes and driving factors of vegetation in Yunnan based on MODIS-NDVI

  • 摘要: 【目的】研究云南省植被时空变化及其影响因素,为区域环境保护及生态环境建设提供理论依据。【方法】基于MODIS-NDVI数据,利用趋势分析法、Hurst指数、残差分析法在不同地形地貌分区尺度上分析2001—2020年云南省植被覆盖时空演变特征,并讨论地形、气候和人类活动因素对其变化的影响。【结果】2001—2020年云南省NDVI整体呈增长趋势,且各分区NDVI变化速率差异较大。云南省平均NDVI呈西高东低、南高北低的布局,各时期NDVI改善面积均大于退化面积,且滇东北地区改善面积最高,为70.84%。未来有10.99%的面积会持续改善,且在不同分区下滇东北地区持续改善比例最高。地形因素对NDVI的影响显著,整体上云南省NDVI随海拔升高而降低,随坡度的增加先增加后减少,在坡向上NDVI呈阴坡大于阳坡的特征。2001—2020年云南省降水与NDVI的相关系数均值为0.0074,呈西负东正的格局,滇东北受降水影响最大。气温与NDVI的相关系数均值为0.0884,滇西南受气温影响最大。人类活动对NDVI的变化均以促进作用为主,土地利用的转变与NDVI的变化具有较强相关性,一系列生态保护工程改善了植被,而建设用地的扩张抑制植被的生长。【建议】因地制宜实施林地生态建设,提高植被种植存活率;完善建设用地规划与管理,防止建设用地快速无序扩张;继续推进生态工程建设,加大林地、草地保护力度。

     

    Abstract: 【Objective】To study the temporal and spatial changes of vegetation in Yunnan and its influencing factors, so as to provide theoretical basis for regional environmental protection and ecological environment construction.【Method】 Based on MODIS-NDVI data,trend analysis,Hurst index and residual analysis were used to analyze the spatio-temporal evolution characteristics of vegetation cover in Yunnan from 2001 to 2020 on different topographic and geomorphic regionalization scales,and the effects of terrain,climate and human activities on the changes were discussed.【Result】From 2001 to 2020,NDVI in Yunnan showed an overall growth trend and the change rate of NDVI in different topographic and geomorphic regions was greatly different. NDVI in Yunnan was high in the west and low in the east,and high in the south and low in the north. The area of NDVI improvement was larger than the area of degradation at all stages,and the area of NDVI improvement was the highest in northeast Yunnan(70.84%). In the future,10.99% of the area would continue to improve,and the northeast Yunnan region had the highest proportion of continuous improvement among different regions. Terrain factors had a significant impact on NDVI. As a whole,NDVI in Yunnan decreased with the increase of altitude, and increased first and then decreased with the increase of slope. In the slope direction,NDVI presented a feature that the negative slope was greater than the positive slope. The average correlation coefficient between precipitation and NDVI in Yunnan from 2001 to 2020 was 0.0074,showing a pattern of west negative and east positive,and northeast Yunnan was most affected by precipitation. The average correlation coefficient between air temperature and NDVI was 0.0884,and southwest Yunnan was the most affected by air temperature. The changes of NDVI were mainly promoted by human activities at each stage. The change of land use had a strong correlation with the change of NDVI. A series of ecological protection projects improved vegetation,while the expansion of construction land inhibited the growth of vegetation.SuggestionImplement forest ecological construction according to local conditions to improve vegetation planting survival rate; improve the planning and management of construction land to prevent the rapid and disorderly expansion of construction land;continue to promote ecological projects and intensify efforts to protect forest lands and grasslands.

     

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