Topographic correction-based retrieval of leaf area index in mountain areas |
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Authors: | Wei Chen Chunxiang Cao |
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Institution: | 1. Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing, 100101, China 2. Graduate University of Chinese Academy of Sciences, Beijing, 100049, China
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Abstract: | Leaf Area Index (LAI) is a key parameter in vegetation analysis and management, especially for mountain areas. The accurate
retrieval of LAI based on remote sensing data is very necessary. In a study at the Dayekou forest center in Heihe watershed
of Gansu Province, we determined the LAI based on topographic corrections of a SPOT-5. The large variation in the mountain
terrain required preprocessing of the SPOT-5 image, except when orthorectification, radiation calibration and atmospheric
correction were used. These required acquisition of surface reflectance and several vegetation indexes and linkage to field
measured LAI values. Statistical regression models were used to link LAI and vegetation indexes. The quadratic polynomial
model between LAI and SAVI (L=0.35) was determined as the optimal model considering the R and R2 value. A second group of
LAI data were reserved to validate the retrieval result. The model was applied to create a distribution map of LAI in the
area. Comparison with an uncorrected SPOT-5 image showed that topographic correction is necessary for determination of LAI
in mountain areas. |
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Keywords: | SPOT-5 image Vegetation Index Leaf Area Index Topographic correction Mountain areas |
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