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Estimation of leaf area index from PROBA/CHRIS hyperspectral multi-angular data

Estimation of leaf area index from PROBA/CHRIS hyperspectral multi-angular data
Estimation of leaf area index from PROBA/CHRIS hyperspectral multi-angular data
Leaf Area Index (LAI) is a key structural and functional biophysical variable of the vegetated surfaces which is important in quantifying evapotranspiration rates and the energy exchange of terrestrial vegetation. Remote sensing offers a method of providing estimates of LAI through the analysis of the Bidirectional Reflectance Distribution Function (BRDF), an angular-dependent surface response. High-resolution, multi-angular and hyperspectral image data from PROBA/CHRIS (Project On-Board Autonomy/ Compact High Resolution Imaging Spectrometer) are used to estimate LAI. The retrieval of LAI is accomplished using the 1D turbid-medium canopy reflectance model, SAIL, coupled with the leaf reflectance model, PROSPECT REDUX. Look-up-tables are generated using scene-specific parameters required to invert the physically based model. Two experiments are performed to examine the contribution of multispectral versus hyperspectral reflectances (nadir direction) and single-look versus multi-look hyperspectral reflectances in deriving the LAI. Image data of the calibration/validation site at Chilbolton, Hampshire, UK are used for the inversion. In addition, ground measurements of LAI are compared with the retrieved LAI estimates. Retrieved LAI estimates using various spectral and directional sampling suggest that the spectro-directional reflectances from CHRIS provides more accurate results than their lower-resolution counterparts such as single-look and multispectral reflectances.
lai, chris, lut, hyperspectral, sail
1-4
Remote Sensing & Photogrammetry Society
Kamalesh, V.L.
6ea368e7-6902-4e73-9c9c-9270b0e292c2
Luckman, A.
964eae91-8877-466b-b230-63a418effbfe
Grey, W.M.F.
498b9257-03b7-45b1-9a99-4adb49c450fb
Milton, E.J.
f6cb5c0d-a5d4-47d7-860f-096de08e0c24
Kamalesh, V.L.
6ea368e7-6902-4e73-9c9c-9270b0e292c2
Luckman, A.
964eae91-8877-466b-b230-63a418effbfe
Grey, W.M.F.
498b9257-03b7-45b1-9a99-4adb49c450fb
Milton, E.J.
f6cb5c0d-a5d4-47d7-860f-096de08e0c24

Kamalesh, V.L., Luckman, A., Grey, W.M.F. and Milton, E.J. (2008) Estimation of leaf area index from PROBA/CHRIS hyperspectral multi-angular data. In Proceedings of the Remote Sensing and Photogrammetry Society Conference: “Measuring Change in the Earth System”. University of Exeter, 15-17 September 2008. Remote Sensing & Photogrammetry Society. pp. 1-4 .

Record type: Conference or Workshop Item (Paper)

Abstract

Leaf Area Index (LAI) is a key structural and functional biophysical variable of the vegetated surfaces which is important in quantifying evapotranspiration rates and the energy exchange of terrestrial vegetation. Remote sensing offers a method of providing estimates of LAI through the analysis of the Bidirectional Reflectance Distribution Function (BRDF), an angular-dependent surface response. High-resolution, multi-angular and hyperspectral image data from PROBA/CHRIS (Project On-Board Autonomy/ Compact High Resolution Imaging Spectrometer) are used to estimate LAI. The retrieval of LAI is accomplished using the 1D turbid-medium canopy reflectance model, SAIL, coupled with the leaf reflectance model, PROSPECT REDUX. Look-up-tables are generated using scene-specific parameters required to invert the physically based model. Two experiments are performed to examine the contribution of multispectral versus hyperspectral reflectances (nadir direction) and single-look versus multi-look hyperspectral reflectances in deriving the LAI. Image data of the calibration/validation site at Chilbolton, Hampshire, UK are used for the inversion. In addition, ground measurements of LAI are compared with the retrieved LAI estimates. Retrieved LAI estimates using various spectral and directional sampling suggest that the spectro-directional reflectances from CHRIS provides more accurate results than their lower-resolution counterparts such as single-look and multispectral reflectances.

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More information

Published date: 15 September 2008
Venue - Dates: Remote Sensing and Photogrammetry Society Conference: “Measuring Change in the Earth System”, Exeter, United Kingdom, 2008-09-14 - 2008-09-16
Keywords: lai, chris, lut, hyperspectral, sail

Identifiers

Local EPrints ID: 63466
URI: http://eprints.soton.ac.uk/id/eprint/63466
PURE UUID: 4b3e797d-0f06-42dc-9f58-c0d2c559a0d0

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Date deposited: 09 Oct 2008
Last modified: 27 Jul 2020 16:40

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