Journal of Geographical Sciences ›› 2011, Vol. 21 ›› Issue (6): 979-993.doi: 10.1007/s11442-011-0894-x

• Climate Change • Previous Articles     Next Articles

Spatio-temporal changes of NDVI and its relation with climatic variables in the source regions of the Yangtze and Yellow rivers

YANG Zhaoping1, GAO Jixi1, ZHOU Caiping2, SHI Peili2, ZHAO Lin3, SHEN Wenshou1, OUYANG Hua2   

  1. 1. Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing 210042, China;
    2. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    3. Observation and Research Station of Qinghai-Tibet Plateau, CAREERI, CAS, Lanzhou 730000, China
  • Received:2011-04-05 Revised:2011-07-06 Online:2011-12-15 Published:2011-10-03
  • Contact: Ouyang Hua, Professor, E-mail: houyang@icimod.org E-mail:houyang@icimod.org
  • About author:Yang Zhaoping (1980-), Ph.D. specialized in ecosystem ecology. E-mail: yangzp04@163.com
  • Supported by:

    National Basic Task Project, No.2006FY110200; Strategic pilot programs of the Chinese Academy of Sciences, No.XDA05060700; Ministry of Environmental Protection Special Funds for Scientific Research on Public Causes, No.200909050

Abstract:

The source regions of the Yangtze and Yellow rivers are important water conservation areas of China. In recent years, ecological deterioration trend of the source regions caused by global climate change and unreasonable resource development increased gradually. In this paper, the spatial distribution and dynamic change of vegetation cover in the source regions of the Yangtze and Yellow rivers are analyzed in recent 10 years based on 1-km resolution multi-temporal SPOTVGT-DN data from 1998 to 2007. Meanwhile, the correlation relationships between air temperature, precipitation, shallow ground temperature and NDVI, which is 3×3 pixel at the center of Wudaoliang, Tuotuohe, Qumalai, Maduo, and Dari meteorological stations were analyzed. The results show that the NDVI values in these two source regions are increasing in recent 10 years. Spatial distribution of NDVI which was consistent with hydrothermal condition decreased from southeast to northwest of the source regions. NDVI with a value over 0.54 was mainly distributed in the southeastern source region of the Yellow River, and most NDVI values in the northwestern source region of the Yangtze River were less than 0.22. Spatial changing trend of NDVI has great difference and most parts in the source regions of the Yangtze and Yellow rivers witnessed indistinct change. The regions with marked increasing trend were mainly distributed on the south side of the Tongtian River, some part of Keqianqu, Tongtian, Chumaer, and Tuotuo rivers in the source region of the Yangtze River and Xingsuhai, and southern Dari county in the source region of the Yellow River. The regions with very marked increasing tendency were mainly distributed on the south side of Tongtian Rriver and sporadically distributed in hinterland of the source region of the Yangtze River. The north side of Tangula Range in the source region of the Yangtze River and Dari and Maduo counties in the source region of the Yellow River were areas in which NDVI changed with marked decreasing tendency. The NDVI change was positively correlated with average temperature, precipitation and shallow ground temperature. Shallow ground temperature had the greatest effect on NDVI change, and the second greatest factor influencing NDVI was average temperature. The correlation between NDVI and shallow ground temperature in the source regions of the Yangtze and Yellow rivers increased significantly with the depth of soil layer.

Key words: source regions of the Yangtze and Yellow rivers, NDVI, spatio-temporal change, temperature, precipitation, shallow ground temperature