Temporal and Spatial Change of Vegetation Cover in the Northwest of China and Factors Analysis Influencing on Vegetations Variation
中国西北地区地表植被覆盖特征的时空变化及影响因子分析

Spatial eigenvectors and temporal coefficients resulting from decomposed NDVI by EOF show that vegetations cover in the northwest of China presented a significantly upward trend from 1982 to 1994, and decreased after 1994. The temporal consistency between annual variations in clouds cover derived from TOVS and land surface feature implies indirectly the land degradation in the northwest of China. Based on the correlation analysis between NDVI and rainfall, two divisions where climatic factors or human activities influences on vegetation cover are marked off. The areas where the correlations is significant, the drought is a principle reason leading to the degeneration of vegetations cover after 1994; another area, such as Yellow River watershed, the drought and human activities are responsible for land degradation.