A clumped-foliage canopy radiative transfer model for a Global Dynamic Terrestrial Ecosystem Model II: Comparison to measurements

Yang, Wen‐Jei; Ni‐Meister, Wenge; Kiang, Nancy Y.; Moorcroft, P. R.; Strahler, Alan H.; Oliphant, A. J.

doi:10.1016/j.agrformet.2010.02.008

Cited by 40 publications

(28 citation statements)

References 37 publications

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“…Scaling leaf conductance as well as optical properties to the canopy scale for the ExoPFT will be done with the new prognostic vegetation canopy radiative transfer scheme, the Analytical Clumped Two-Stream (ACTS) model Yang et al 2010). This model has recently been incorporated in the Ent TBM.…”

Section: Ground Hydrology Albedo and Surface Vegetationmentioning

confidence: 99%

Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics (ROCKE-3D) 1.0: A General Circulation Model for Simulating the Climates of Rocky Planets

Way

Aleinov

Amundsen

et al. 2017

ApJS

142

141

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Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics(ROCKE-3D) is a 3-Dimensional General Circulation Model (GCM) developed at the NASA Goddard Institute for Space Studies for the modeling of atmospheres of Solar System and exoplanetary terrestrial planets. Its parent model, known as ModelE2 (Schmidt et al. 2014), is used to simulate modern and 21st Century Earth and near-term paleo-Earth climates. ROCKE-3D is an ongoing effort to expand the capabilities of ModelE2 to handle a broader range of atmospheric conditions including higher and lower atmospheric pressures, more diverse chemistries and compositions, larger and smaller planet radii and gravity, different rotation rates (slowly rotating to more rapidly rotating than modern Earth, including synchronous rotation), diverse ocean and land distributions and topographies, and potential basic biosphere functions. The first aim of ROCKE-3D is to model planetary atmospheres on terrestrial worlds within the Solar System such as paleo-Earth, modern and paleo-Mars, paleo-Venus, and Saturn's moon Titan. By validating the model for a broad range of temperatures, pressures, and atmospheric constituents we can then expand its capabilities further to 2 those exoplanetary rocky worlds that have been discovered in the past and those to be discovered in the future. We discuss the current and near-future capabilities of ROCKE-3D as a community model for studying planetary and exoplanetary atmospheres.3

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Section: Ground Hydrology Albedo and Surface Vegetationmentioning

confidence: 99%

Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics (ROCKE-3D) 1.0: A General Circulation Model for Simulating the Climates of Rocky Planets

Way

Aleinov

Amundsen

et al. 2017

ApJS

142

141

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“…First, because the impacts of trunks on the total scanned data and LAI estimates strongly vary during the leaf-off and leaf-on seasons [46], distinguishing between wood and foliage return signals is important for directly retrieving leaf area. The classification accuracy is particularly dependent on the feature selection, rather than the classification algorithm itself.…”

Section: Recommendationsmentioning

confidence: 99%

A Novel Approach for Retrieving Tree Leaf Area from Ground-Based LiDAR

Yun

et al. 2016

Remote Sensing

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Abstract:Leaf area is an important plant canopy structure parameter with important ecological significance. Light detection and ranging technology (LiDAR) with the application of a terrestrial laser scanner (TLS) is an appealing method for accurately estimating leaf area; however, the actual utility of this scanner depends largely on the efficacy of point cloud data (PCD) analysis. In this paper, we present a novel method for quantifying total leaf area within each tree canopy from PCD. Firstly, the shape, normal vector distribution and structure tensor of PCD features were combined with the semi-supervised support vector machine (SVM) method to separate various tree organs, i.e., branches and leaves. In addition, the moving least squares (MLS) method was adopted to remove ghost points caused by the shaking of leaves in the wind during the scanning process. Secondly, each target tree was scanned using two patterns, i.e., one scan and three scans around the canopy, to reduce the occlusion effect. Specific layer subdivision strategies according to the acquisition ranges of the scanners were designed to separate the canopy into several layers. Thirdly, 10% of the PCD was randomly chosen as an analytic dataset (ADS). For the ADS, an innovative triangulation algorithm with an assembly threshold was designed to transform these discrete scanning points into leaf surfaces and estimate the fractions of each foliage surface covered by the laser pulses. Then, a novel ratio of the point number to leaf area in each layer was defined and combined with the total number of scanned points to retrieve the total area of the leaves in the canopy. The quantified total leaf area of each tree was validated using laborious measurements with a LAI-2200 Plant Canopy Analyser and an LI-3000C Portable Area Meter. The results showed that the individual tree leaf area was accurately reproduced using our method from three registered scans, with a relative deviation of less than 10%. Nevertheless, estimations from only one scan resulted in a deviation of >25% in the retrieved individual tree leaf area due to the occlusion effect. Indeed, this study provides a novel connection between leaf area estimates and scanning sensor configuration and supplies an interesting method for estimating leaf area based on PCD.

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“…GORT has been used to model the physical aspects of discontinuous plant canopies such as gap fraction, radiation transmission, and bi-directional reflectance (Ni et al, 1997(Ni et al, , 1999Xin et al, 2012), and has been validated under a variety of environmental conditions (Liu et al, 2008). Recent efforts have been made to develop and evaluate a simplified GORT model for the use in coupled global dynamic terrestrial ecosystem models Yang et al, 2010). Despite these successful applications, the current version of the GORT model does not have analytical solutions for radiation absorption by sunlit and shaded leaves, though previous studies have tried to solve the process of multiple scattering between canopy and background in an iterative manner (Song et al, 2009).…”

Section: Q Xin Et Al: Modeling Photosynthesis Of Discontinuous Planmentioning

confidence: 99%

Modeling photosynthesis of discontinuous plant canopies by linking the Geometric Optical Radiative Transfer model with biochemical processes

Xin

Gong

2015

Biogeosciences

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Abstract. Modeling vegetation photosynthesis is essential for understanding carbon exchanges between terrestrial ecosystems and the atmosphere. The radiative transfer process within plant canopies is one of the key drivers that regulate canopy photosynthesis. Most vegetation cover consists of discrete plant crowns, of which the physical observation departs from the underlying assumption of a homogenous and uniform medium in classic radiative transfer theory. Here we advance the Geometric Optical Radiative Transfer (GORT) model to simulate photosynthesis activities for discontinuous plant canopies. We separate radiation absorption into two components that are absorbed by sunlit and shaded leaves, and derive analytical solutions by integrating over the canopy layer. To model leaf-level and canopylevel photosynthesis, leaf light absorption is then linked to the biochemical process of gas diffusion through leaf stomata. The canopy gap probability derived from GORT differs from classic radiative transfer theory, especially when the leaf area index is high, due to leaf clumping effects. Tree characteristics such as tree density, crown shape, and canopy length affect leaf clumping and regulate radiation interception. Modeled gross primary production (GPP) for two deciduous forest stands could explain more than 80 % of the variance of flux tower measurements at both near hourly and daily timescales. We demonstrate that ambient CO 2 concentrations influence daytime vegetation photosynthesis, which needs to be considered in biogeochemical models. The proposed model is complementary to classic radiative transfer theory and shows promise in modeling the radiative transfer process and photosynthetic activities over discontinuous forest canopies.

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A clumped-foliage canopy radiative transfer model for a Global Dynamic Terrestrial Ecosystem Model II: Comparison to measurements

Cited by 40 publications

References 37 publications

Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics (ROCKE-3D) 1.0: A General Circulation Model for Simulating the Climates of Rocky Planets

Resolving Orbital and Climate Keys of Earth and Extraterrestrial Environments with Dynamics (ROCKE-3D) 1.0: A General Circulation Model for Simulating the Climates of Rocky Planets

A Novel Approach for Retrieving Tree Leaf Area from Ground-Based LiDAR

Modeling photosynthesis of discontinuous plant canopies by linking the Geometric Optical Radiative Transfer model with biochemical processes

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