| Title | Correction to the plant canopy gap-size analysis theory used by the Tracing Radiation and Architecture of Canopies instrument |
| Download | Downloads (Preprint) |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Leblanc, S G |
| Source | Applied Optics vol. 41, no. 36, 2002 p. 7671-7678, https://doi.org/10.1364/AO.41.007667 |
| Year | 2002 |
| Alt Series | Earth Sciences Sector, Contribution Series 20043058 |
| Publisher | The Optical Society |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Subjects | geophysics; optical properties; vegetation; remote sensing; analyses; correlations |
| Released | 2002 12 20 |
| Abstract | A plant canopy gap-size analyzer, the Tracing Radiation and Architecture of Canopies (TRAC), developed by Chen and Cihlar [Appl Opt. 34, 6211(1995)] and commercialized and by 3rd Wave Engineering
(Nepean, Canada), has been used around the world to quantify the fraction of photosynthetically activeradiation absorbed by plant canopies, the leaf area index (LAI), and canopy architectural parameters. The TRAC is walked under a canopy along
transects to measure sunflecks that are converted into a gap-size distribution. A numerical gap-removal technique is performed to remove gaps that are not theoretically possible in a random canopy. The resulting reduced gap-size distribution is used
to quantify the heterogeneity of the canopy and to improve LAI measurements. It is explicitly shown here that the original derivation of the clumping index was missing a normalization factor. For a very clumped canopy with a large gap faction, the
resulting LAI can be more than 100% smaller than previously estimated. A test case is used to demonstrate that the new clumping index derivation allows a more accurate change of LAI to be measured. |
| GEOSCAN ID | 219860 |
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