干旱区生态环境知识资源中心

The interaction of meteorological factors and groundwater depth affects vegetation coverage and growth, particularly in semi-arid regions where groundwater is extracted for human use. This paper analyzed the characteristics of temporal and spatial variations in the Normalized Difference Vegetation Index (NDVI) between 1998 and 2008 to clarify the response of NDVI to variations in meteorological factors and groundwater depth in the Heihe River Basin, China. The results indicated that: (1) there was a statistically significant response of NDVI to temperature variation, and this was greater than the response to precipitation. Partial years showed a time-lag in response to temperature and precipitation, and NDVI-temperature had a faster response time than NDVI-precipitation. (2) Groundwater depth less than 7.3 m had the greatest effect on NDVI. Salinization, the capillary height and the maximum vegetation root zone were the main factors to increase or reduce the growth of vegetation. The relationship between NDVI and groundwater depth could be fitted with a logistic correlation curve.