2000~2015年长三角地区植被NPP时空变化特征及其驱动因素

Temporal and Spatial Variation of Vegetation NPP and Its Driving Factors in Yangtze River Delta during 2000~2015

摘要: 长三角地区是我国经济发展最快、城市化进程最活跃的地区之一，该区域植被变化受到气候变化和人类活动的影响。本文基于2000~2015年MODIS-NDVI数据，利用CASA模型估算研究区NPP年均值，采用趋势分析、变异系数、偏相关分析、复相关分析等方法，分析近16年长三角地区植被NPP的空间格局及动态演变特征，分析NPP与气候因子的相关关系，探究气候因子对植被NPP的驱动作用。研究结果表明，1) 2000年~2015年长三角地区NPP多年均值为492.2 gC/m²，空间分布上浙江省植被NPP均值最高，为627.4 gC/m²，上海市植被NPP均值最低，为296.8 gC/m²。2) 近16年来，时间尺度上长三角地区年均NPP呈波动上升趋势，上升速率为3.4 gC/(m²∙a)，NPP年均最高值为2014年的548.8 gC/m²，最低值为2000年的448.4 gC/m²，最大相对偏移量为11.5%，研究区植被初级生产力整体变异程度稳定，且变异系数明显的地区在水系和城市周围。3) 2000~2015年间，植被NPP与降水呈正相关的区域占总面积的78.8%，与气温呈正相关的区域占总面积的56.7%；植被NPP受气候因子影响的地区占8.05%，其中降水对植被NPP变化的影响较大，非气候因子影响占91.9%，主要体现在人类活动的影响。研究结果为长三角地区植被恢复和生态保护提供参考依据。

Abstract: The Yangtze River Delta region is one of the regions with the fastest economic development and the most active urbanization process in China. Vegetation change in this region is affected by climate change and human activities. Based on MODIS-NDVI data from 2000 to 2015, and CASA model was used to estimate the annual mean value of NPP in the study area. Trend analysis, coefficient of variation, partial correlation analysis and complex correlation analysis were used to analyze the spatial pattern and dynamic evolution characteristics of NPP in Yangtze River Delta region in recent 16 years, and the correlation between NPP and climate factors was analyzed. To explore the driving effect of climate factors on NPP of vegetation. The results show that: 1) The annual mean value of NPP in Yangtze River Delta region from 2000 to 2015 is 492.2 gC/m² and in terms of spatial distribution, the mean NPP of vegetation in Zhejiang province was the highest 627.4 gC/m², the mean NPP of vegetation in Shanghai was 296.8 gC/m². 2) In recent 16 years, the annual average NPP in the Yangtze River Delta showed a fluctuating trend of increase, with an increased rate of 3.4 gC/(m²∙a), the maximum annual value of NPP was 548.8 gC/m2 in 2014, the lowest value was 448.4 gC/m² in 2000, the maximum relative offset is 11.5%. The overall variation degree of vegetation primary productivity in the study area was stable, and the areas with obvious variation coefficient were around water systems and cities. 3) From 2000 to 2015, 78.8% of the total area had a positive correlation between NPP and precipitation, and 56.7% of the total area had a positive correlation with temperature. The NPP of vegetation was affected by climate factors in 8.05% of the regions, of which precipitation had a greater impact on NPP, and non-climate factors accounted for 91.9%, which was mainly reflected in the impact of human activities. The results provide reference for vegetation restoration and ecological protection in Yangtze River Delta region.