Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (2): 319-327.DOI: 10.3773/j.issn.1005-264x.2008.02.008

Special Issue: 青藏高原植物生态学:遥感生态学

• Research Articles • Previous Articles     Next Articles


GUO Ni1(), ZHU Yan-Jun2, WANG Jie-Min3, DENG Chao-Ping4   

  1. 1Institute of Arid Meteorology, China Meteorology Administration, Lanzhou, Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province, Key Open Laboratory of Arid Climate Change and Disaster Reduction of China Meteorology Administration, Lanzhou, Gansu 730020, China
    2National Meteorological Information Centre, Beijing 100081, China
    3Cold and Arid Regions Environmental and Engineering, Lanzhou 730000, China
    4Hunan Province Meteorological Observatory, Changsha 410007, China
  • Received:2006-09-19 Accepted:2006-12-03 Online:2008-09-19 Published:2008-03-30
  • Contact: GUO Ni


Aims We sought to understand the impacts of climate change on vegetation in Northwest China and the relationship between normalized difference vegetation index (NDVI) and climate elements.
Methods Correlation analyses were done using the GIMMS NDVI data and monthly mean temperature and precipitation data from January 1982 to December 2003. We selected different regions in Northwest China, representing major types of vegetation, such as forest, grassland, oasis, and rain-fed cropland, for detailed study.
Important findings We found strong correlations between NDVI and temperature/precipitation, except for the Gobi and other desert areas. Correlation coefficients of NDVI and temperature are higher than them of NDVI and precipitation in almost all regions, particularly for the Hexi Corridor and most of the Xinjiang area. During the vegetation growth period, temperature has greater effect on the various types of vegetation than precipitation. The forests in the higher latitude of Xinjiang area are most sensitive to temperature. This sensitivity reduces in sequence from forests to oases, grasslands and unirrigated croplands. Grasslands are most sensitive to precipitation. The sensitivity to precipitation decreases from grasslands to forests, unirrigated croplands, and oases. In summer, the NDVI of forest decreased during the last 22 years, especially forest in the eastern portion of the northwest. This was related to decreases of precipitation and increases of temperature in these areas. The NDVI in most grassland increased. The trends were significant for high cold meadow and halophytic meadow. Climate warming is the main reason for grass growth speeding up. For oases, the NDVI increases were the most significant. The trends were the highest in Xinjiang oasis. Climate warming was one of the factors driving increases in NDVI. The impact of human activities, such as oasis expanding, crop structure change and crop varieties on the NDVI variation cannot be ignored. The NDVI interannual change was high and varied among the unirrigated croplands. NDVI had a strong positive correlation with precipitation and a negative correlation with temperature. The temperature increase and the precipitation decrease caused the NDVI decrease in these areas.

Key words: NDVI, vegetation, climate change, correlation analysis, Northwest China