关键词: 京津冀地区, NDVI, 植被覆盖变化, 气候因子

Abstract:

Vegetation dynamics and their coupled relations with climate are current research hot spots in exploring how terrestrial ecosystems respond to climate systems. Beijing-Tianjin-Hebei Metropolis Circle, one of the three major economic circles located in the eastern part of China, has been experiencing a rapid development as well as a severe change in eco-environment. The analysis of NDVI’s (Normalized Difference Vegetation Index) spatial-temporal dynamics and the exploration of relevant key climatic driving factors have special significance in the research of ecological environment change in Beijing-Tianjin-Hebei Metropolis Circle. In order to explore the vegetation dynamics and the impact of climate change on vegetation cover in Beijing-Tianjin-Hebei Metropolis Circle from 2001 to 2013, we adopted NDVI data of MOD13A3 to study the trend and spatial pattern of this region using linear regression, with the assistance of precipitation and average temperature data from the growing season. The climatic driving forces of vegetation cover change were discussed using partial correlation analysis and multiple correlation analysis. The results indicate that NDVI had increased gradually during this period, which showed a good development trend for the vegetation cover in this region. The average partial correlation coefficients between NDVI and precipitation, and between NDVI and average temperature are 0.20 and -0.14 respectively, which indicate that NDVI is positively correlated with precipitation and negatively correlated with the average temperature during the growing season at the annual variation level. Furthermore, the impact of precipitation on NDVI is greater than temperature. Analysis of the driving factors on vegetation change shows that about 89.63% of the study area was impacted by non-climatic driving factor, while 5.68% was driven by a combined climatic factor of both precipitation and temperature, and 4.51% and 0.18% was driven by precipitation and temperature separately. As a result, it is evident to conclude that the vegetation change in this region is mainly affected by human activities.

Key words: Beijing-Tianjin-Hebei Metropolis Circle, NDVI, vegetation cover change, climatic factors