Title: Estimation of leaf area index in southern Sweden with optimal modelling and Landsat 7 ETM+Scene
Abstract: Canopy reflectance models are used as a means of estimating vegetation parameters and
simulating reflectance signatures of vegetation surfaces. A forest canopy reflectance
model is tested on deciduous forest collections in southern Sweden. A sensitivity analysis
is performed to study how large influence each parameter has on the simulated
reflectance. Thorough field measurements of the forest collections are done were the
structural parameters are measured. The branch area index and leaf area index are
measured with the Li-Cor LAI-2000 optical sensor, and two methods are tested to obtain
leaf area index from effective leaf area index. The field data are used together with
LOPEX leaf biophysical data to simulate the reflectance from the forest collections. The
obtained reflectance is correlated against atmospheric influence corrected Landsat 7 ETM
reflectance data. Atmospheric correction of the satellite data is done with a radiative
transfer model named 6S, and atmospheric input data from SMHI (the Swedish
Meteorological and Hydrological Institute). The forest model is further tested in inverse
mode to obtain LAI. The inverted LAI values are compared to the measured ones. A
sensitivity analysis showed that crown radius, chlorophyll content and leaf structural
parameter are the most important parameters. LAI, BAI and stand density showed
moderate importance while the other parameters showed low influence on the calculated
reflectance.
The correlation between modelled and measured reflectance was very low with
the best correlation in ETM 5 (r = 0.55). The inversion of the model yielded low
correlations except for collections with one size class. These collections proved to be
more easily modelled.
Publication Year: 2000
Publication Date: 2000-01-01
Language: en
Type: article
Access and Citation
Cited By Count: 20
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