A Preliminary Approach on the Synchronically Ground Based Measurement of Spectral Reflectance, NDVI, LAI, and the Temperature and Moisture of Soils

摘要

Ground based measurements on spectral reflectance, vegetation indices, leaf area index and the temperature and water content of soil with different land covers play key roles on both the evaluation on image information retrieval models, and environmental monitoring with remote sensing technology. In early- and mid-July, 2007, the authors conducted a field campaign for the synthetic measurement of ground spectrum reflectance, normalized difference vegetation index (NDVI), leaf area index (LAI), as well as the water content, saline, and temperature of soil with a series of portable instruments, on different kinds of land use/land cover. Following conclusions were got: (1) Either for alpine meadow, or for farm land with paddy, harvest wheat, maize, or bean, their diurnal variations of NDVI are small. The diurnal variations of spectral reflectance and LAI are evident and irregular. The possible reason for the variations of spectral reflectance is up to weather condition; (2) Synthetic correlation analysis on both NDVI and LAI of 9 kinds of land use/land cover from 23 measuring sites shows that the linear relationship between both is good. But the diurnal variation of LAI and the saturation effect of NDVI induce uncertainty of this relationship.