Journal of Geographical Sciences ›› 2014, Vol. 24 ›› Issue (6): 963-979.doi: 10.1007/s11442-014-1131-1

• Research Articles • Previous Articles     Next Articles

Inter-annual variations in vegetation and their response to climatic factors in the upper catchments of the Yellow River from 2000 to 2010

Ran CAO1,2(), Weiguo JIANG1,2(), Lihua YUAN1,2, Wenjie WANG3, Zhongliang LV4, Zheng CHEN1,2   

  1. 1. State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
    2. Key Laboratory of Environmental Change and Natural Disaster, Beijing Normal University, Beijing 100875, China
    3. Chinese Research Academy of Environmental Sciences, Beijing 100012, China
    4. National Meteorological Center of CMA, Beijing 100081, China
  • Received:2014-05-30 Accepted:2014-07-10 Online:2014-06-20 Published:2014-06-20
  • About author:

    Author: Cao Ran (1990-), Graduate Student, specialized in ecological remote sensing and natural hazard and risk analysis. E-mail: caoran_1990@163.com.

  • Supported by:
    National Natural Science Foundation of China, No.41171318.National Key Technology Support Program, No.2012BAH32B03.No.2012BAH33B05.The Remote Sensing Investigation and Assessment Project for Decade-Change of the National Ecological Environment (2000-2010)

Abstract:

To understand the variations in vegetation and their correlation with climate factors in the upper catchments of the Yellow River, China, Normalized Difference Vegetation Index (NDVI) time series data from 2000 to 2010 were collected based on the MOD13Q1 product. The coefficient of variation, Theil-Sen median trend analysis and the Mann-Kendall test were combined to investigate the volatility characteristic and trend characteristic of the vegetation. Climate data sets were then used to analyze the correlation between variations in vegetation and climate change. In terms of the temporal variations, the vegetation in this study area improved slightly from 2000 to 2010, although the volatility characteristic was larger in 2000-2005 than in 2006-2010. In terms of the spatial variation, vegetation which is relatively stable and has a significantly increasing trend accounts for the largest part of the study area. Its spatial distribution is highly correlated with altitude, which ranges from about 2000 to 3000 m in this area. Highly fluctuating vegetation and vegetation which showed a significantly decreasing trend were mostly distributed around the reservoirs and in the reaches of the river with hydropower developments. Vegetation with a relatively stable and significantly decreasing trend and vegetation with a highly fluctuating and significantly increasing trend are widely dispersed. With respect to the response of vegetation to climate change, about 20-30% of the vegetation has a significant correlation with climatic factors and the correlations in most areas are positive: regions with precipitation as the key influencing factor account for more than 10% of the area; regions with temperature as the key influencing factor account for less than 10% of the area; and regions with precipitation and temperature as the key influencing factors together account for about 5% of the total area. More than 70% of the vegetation has an insignificant correlation with climatic factors.

Key words: correlation analysis, coefficient of variation, hydropower development, Mann-Kendall test, NDVI time series data, Theil-Sen median trend analysis, Yellow River, China