A review on the theory of photon transport in leaf canopies

Myneni, Ranga B.; Ross, Juhan; Asrar, Ghassem

doi:10.1016/0168-1923(89)90002-6

Cited by 323 publications

(128 citation statements)

References 329 publications

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“…The algorithm uses photon transport theory to estimate both the radiation regime within the vegetation canopy and the radiant exitance, based on the architecture of individual plants and the entire canopy, optical properties of vegetation elements and soil atmospheric conditions (Knyazikhin, 1999;Myneni et al 1989). The MODIS algorithm requires a land cover classification (also derived from MODIS data) to model the radiative transfer over larger areas.…”

Section: Physical Models For Determination Of Absorbed Parmentioning

confidence: 99%

The use of remote sensing in light use efficiency based models of gross primary production: A review of current status and future requirements

Hilker

Coops

Wulder

et al. 2008

Science of The Total Environment

255

187

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Section: Physical Models For Determination Of Absorbed Parmentioning

confidence: 99%

The use of remote sensing in light use efficiency based models of gross primary production: A review of current status and future requirements

Hilker

Coops

Wulder

et al. 2008

Science of The Total Environment

255

187

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“…The model is thus formulated in 11 parameters, eight at the 'leaf-level' (a vis , a NIR , t vis , and t NIR each for leaves and stems) and three canopy-level or 'structural' parameters, (L, S, and w). Note that the degree to which foliage is clumped is sometimes considered an additional parameter; in this version of the model the foliage is not clumped but randomly located (Myneni et al, 1989).…”

Section: Albedo Calculations and Parameter Estimationmentioning

confidence: 99%

“…Manabe, 1969;Dickinson et al, 1986;Milly & Shmakin, 2002), or (2) a calculation of albedo using an approximation of canopy radiation transport. In these approximation methods, instead of solving the full transport equation, the canopy is assumed horizontal, and the radiation field is divided into several components (Myneni et al, 1989). The simplest approach is to separate the radiation into upward and downward propagating diffuse streams based on the equations of Kubelka and Munk (see Kubelka, 1948).…”

Section: Introductionmentioning

confidence: 99%

Albedo estimates for land surface models and support for a new paradigm based on foliage nitrogen concentration

Hollinger

Ollinger

Richardson

et al. 2010

Global Change Biology

153

106

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; Schmid, H. P.; Stoy, P. C.; Suyker, Andrew E.; and Verma, Shashi, "Albedo estimates for land surface models and support for a new paradigm based on foliage nitrogen concentration" (2010 Albedo estimates for land surface models and support for a new paradigm based on foliage nitrogen concentration AbstractVegetation albedo is a critical component of the Earth's climate system, yet efforts to evaluate and improve albedo parameterizations in climate models have lagged relative to other aspects of model development. Here, we calculated growing season albedos for deciduous and evergreen forests, crops, and grasslands based on over 40 site-years of data from the AmeriFlux network and compared them with estimates presently used in the land surface formulations of a variety of climate models. Generally, the albedo estimates used in land surface models agreed well with this data compilation. However, a variety of models using fixed seasonal estimates of albedo overestimated the growing season albedo of northerly evergreen trees. In contrast, climate models that rely on a common two-stream albedo submodel provided accurate predictions of boreal needle-leaf evergreen albedo but overestimated grassland albedos. Inverse analysis showed that parameters of the two-stream model were highly correlated. Consistent with recent observations based on remotely sensed albedo, the AmeriFlux dataset demonstrated a tight linear relationship between canopy albedo and foliage nitrogen concentration (for forest vegetation: albedo 5 0.01 1 0.071%N, r 2 5 0.91; forests, grassland, and maize: albedo 5 0.02 1 0.067%N, r 2 5 0.80). However, this relationship saturated at the higher nitrogen concentrations displayed by soybean foliage. We developed similar relationships between a foliar parameter used in the two-stream albedo model and foliage nitrogen concentration. These nitrogen-based relationships can serve as the basis for a new approach to land surface albedo modeling that simplifies albedo estimation while providing a link to other important ecosystem processes.

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“…To our knowledge, with the exception of the pioneering work of Kuusk (1995), no deterministic method has yet been found for computing 8(2) from canopy structure measurements, but it can be obtained empirically from comparison of measured and simulated gap fractions (e.g. Sinclair and Lemon, 1974;Sinclair and Knoerr, 1982;Neumann et al, 1989;Myneni et al, 1989;Baret et al, 1993;Andrieu et al, 1997;Chen et al, 1997 …”

Section: (2)k(θ)mentioning

confidence: 99%

PAR extinction in shortgrass ecosystems: effects of clumping, sky conditions and soil albedo

Nouvellon

Bégué

Moran

et al. 2000

Agricultural and Forest Meteorology

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The amount of photosynthetically active radiation (PAR) absorbed by a canopy (APAR) is an important driving variable for vegetation processes such as photosynthesis. PAR extinction in clumped canopies of shortgrass ecosystems is the focus of this paper.Directional gap fractions estimated at peak biomass on several Mexican shortgrass ecosystems with a hemispherical radiation sensor (Li-Cor LAI-2000) were higher than those predicted by a Poisson model assuming a random leaf dispersion. LAI-2000-estimated gap fractions, together with independent estimations of plant area index (PAI), and leaf and stem angle distribution (LSAD) were used for estimating the angular course of a leaf dispersion parameter 8(2). Radiation extinction coefficients simulated for all solar zenith angles using Markov chain processes and estimated 8(2) were subsequently incorporated in a simple radiative transfer model for estimating the efficiencies of instantaneous and daily integrated PAR interception and absorption and for studying the effects of clumping, sky conditions and soil albedo on PAR absorption.For clear sky condition, instantaneous PAR absorption showed marked directional effects, therefore indicating that using a constant extinction coefficient in canopy photosynthesis models working at hourly time step would be inaccurate. The effects of clumping, sky conditions and soil albedo were all found to be significant for low PAI, and decreased with higher PAI. As shortgrass ecosystems are characterized by low PAI, neglecting these effects would give inaccurate estimations of PAR absorption.Daily PAR absorption was found to be significantly higher than PAR interception for low PAI, especially when soil albedo was high, and lower than PAR interception for high PAI.These results indicate that in canopy photosynthesis models where APAR is estimated 3 from simple exponential like relationships calibrated using PAR interception measurements, the PAR available for photosynthesis might be significantly underestimated in the first stages of the growth, and may be overestimated in the later stages of the growing season.

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A review on the theory of photon transport in leaf canopies

Cited by 323 publications

References 329 publications

The use of remote sensing in light use efficiency based models of gross primary production: A review of current status and future requirements

The use of remote sensing in light use efficiency based models of gross primary production: A review of current status and future requirements

Albedo estimates for land surface models and support for a new paradigm based on foliage nitrogen concentration

PAR extinction in shortgrass ecosystems: effects of clumping, sky conditions and soil albedo

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