RICE SCIENCE ›› 2007, Vol. 14 ›› Issue (3): 195-203 .

• Research Paper • Previous Articles     Next Articles

New Vegetation Index and Its Application in Estimating Leaf Area Index
of Rice

WANG Fu-min 1, HUANG Jing-feng 1, TANG Yan-lin 2, WANG Xiu-zhen 3   

  1. 1 Institute of Agriculture Remote Sensing & Information System Application, Zhejiang University, Hangzhou 310029, China; 2 School of
    Sciences, Guizhou University, Guiyang 550025, China; 3 Zhejiang Institute of Meteorological Sciences, Hangzhou 310029, China
  • Received:2006-12-19 Online:2007-09-28 Published:2007-09-28
  • Contact: HUANG Jing-feng
  • Supported by:

    the National Natural Science Foundation of China (Grant No. 40571115) and the Sci & Tech Basic Work Program, the Ministry of Science and Technology, China (Grant No.2003DEA2C010-13).

Abstract: Leaf area index (LAI) is an important characteristic of land surface vegetation system, and is also a key parameter
for the models of global water balancing and carbon circulation. By using the reflectance values of Landsat-5 blue, green and
red channels simulated from rice reflectance spectrum, the sensitivities of the bands to LAI were analyzed, and the response
and capability to estimate LAI of various NDVIs (normalized difference vegetation indices), which were established by
substituting the red band of general NDVI with all possible combinations of red, green and blue bands, were assessed. Finally,
the conclusion was tested by rice data at different conditions. The sensitivities of red, green and blue bands to LAI were
different under various conditions. When LAI was less than 3, red and blue bands were more sensitive to LAI. Though green
band in the circumstances was less sensitive to LAI than red and blue bands, it was sensitive to LAI in a wider range. When
the vegetation indices were constituted by all kinds of combinations of red, green and blue bands, the premise for making the
sensitivity of these vegetation indices to LAI be meaningful was that the value of one of the combinations was greater than
0.024, i.e. visible reflectance (VIS)>0.024. Otherwise, the vegetation indices would be saturated, resulting in lower estimation
accuracy of LAI. Comparison on the capabilities of the vegetation indices derived from all kinds of combinations of red, green
and blue bands to LAI estimation showed that GNDVI (Green NDVI) and GBNDVI (Green-Blue NDVI) had the best relations
with LAI. The capabilities of GNDVI and GBNDVI to LAI estimation were tested under different circumstances, and the same
result was acquired. It suggested that GNDVI and GBNDVI performed better to predict LAI than the conventional NDVI.

Key words: vegetation index, rice, leaf area index, reflectance spectrum, remote sensing