Inversion of a radiative transfer model for estimating vegetation LAI and chlorophyll in a heterogeneous grassland

Radiative transfer models have seldom been applied for studying heterogeneous grassland canopies. Here, the potential of radiative transfer modeling to predict LAI and leaf and canopy chlorophyll contents in a heterogeneous Mediterranean grassland is investigated. The widely used PROSAIL model was i...

Full description

Saved in:
Bibliographic Details
Published in:Remote sensing of environment Vol. 112; no. 5; pp. 2592 - 2604
Main Authors: Darvishzadeh, Roshanak, Skidmore, Andrew, Schlerf, Martin, Atzberger, Clement
Format: Journal Article
Language:English
Published: New York, NY Elsevier Inc 15.05.2008
Elsevier Science
Subjects:
ancillary information
Animal, plant and microbial ecology
Applied geophysics
Biological and medical sciences
canopy biophysical variables
Canopy chlorophyll
Earth sciences
Earth, ocean, space
Exact sciences and technology
Fundamental and applied biological sciences. Psychology
General aspects. Techniques
Grassland
Hyperspectral
Internal geophysics
LAI
Leaf chlorophyll
leaf-area index
LUT
Model inversion
neural-network
optical-properties
precision agriculture
Radiative transfer model
reflectance data
remote-sensing data
retrieval
satellite data
Teledetection and vegetation maps
MED
Grassland
Radiative transfer model
Model inversion
LAI
Hyperspectral
LUT
Canopy chlorophyll
Leaf chlorophyll
Spectroradiometry
stratification
radiative transfer
vegetation
Spectral data
grasslands
LA1
models
inverse problem
Prediction
chlorophyll
Plant leaf
utilization
heterogeneity
Measurement in situ
Content
Canopy(vegetation)
Reflectance
Leaf area index
ISSN:0034-4257, 1879-0704
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Radiative transfer models have seldom been applied for studying heterogeneous grassland canopies. Here, the potential of radiative transfer modeling to predict LAI and leaf and canopy chlorophyll contents in a heterogeneous Mediterranean grassland is investigated. The widely used PROSAIL model was inverted with canopy spectral reflectance measurements by means of a look-up table (LUT). Canopy spectral measurements were acquired in the field using a GER 3700 spectroradiometer, along with simultaneous in situ measurements of LAI and leaf chlorophyll content. We tested the impact of using multiple solutions, stratification (according to species richness), and spectral subsetting on parameter retrieval. To assess the performance of the model inversion, the normalized RMSE and R2 between independent in situ measurements and estimated parameters were used. Of the three investigated plant characteristics, canopy chlorophyll content was estimated with the highest accuracy (R2=0.70, NRMSE=0.18). Leaf chlorophyll content, on the other hand, could not be estimated with acceptable accuracy, while LAI was estimated with intermediate accuracy (R2=0.59, NRMSE=0.18). When only sample plots with up to two species were considered (n=107), the estimation accuracy for all investigated variables (LAI, canopy chlorophyll content and leaf chlorophyll content) increased (NRMSE=0.14, 0.16, 0.19, respectively). This shows the limits of the PROSAIL radiative transfer model in the case of very heterogeneous conditions. We also found that a carefully selected spectral subset contains sufficient information for a successful model inversion. Our results confirm the potential of model inversion for estimating vegetation biophysical parameters at the canopy scale in (moderately) heterogeneous grasslands using hyperspectral measurements.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0034-4257
1879-0704
DOI:10.1016/j.rse.2007.12.003