干旱区生态环境知识资源中心

Vegetation is important factor in global climate variability and hence plays I key role in the complex interaction between land surface and atmosphere. In this stud-v, we analyzed vegetation water content (VWC), leaf area index (LAI), and normalized difference vegetation index (NDVI) and land surface temperature (Ts) from AMSR-E (Advanced Microwave Scanning Radiometer for EOS) and MODIS (Moderate Imaging Sepectrodiometer). For spatial analysis of the relationship between the four variables we selected three regions which have climatically differing characteristics: NAMS (North America Monsoon system) region, SGP (South Great Plains) region, and Little River Watershed in Tifton, GA. Also temporal analyses were performed by comparing of 2003 and 2004. From the introduction of normalized vegetation water content (NVWC) derived from satellite-derived VWC and LAI data, amount of water in individual leaves has been estimated and yielded significant correlation with NDVI and Ts. The analysis 4 three regions in NVWC and NDVI relationship shows their negative exponential relation, and Ts and NDVI relationship (TvX relationship) is inversely proportional. This correlation between these variables are higher in the more arid areas such as NAMS regions, and becomes; less correlated in the more humid and more vegetated regions such as east areas of Georgia. Moreover, land cover map is used to exam how the different vegetation types are related to the land and atmospheric variables, and it is identified that the regional distribution of each vegetation type reflects its biological characteristics related to water and its growing environment.