Quantifying leaf optical properties with spectral invariants theory

REMOTE SENSING OF ENVIRONMENT

卷:253

Article

Wu, Shengbiao¹  Zeng, Yelu^2,3  Hao, Dalei²  Liu, Qinhuo⁴  Li, Jing⁴  Chen, Xiuzhi⁵  Asrar, Ghassem R.⁶  Yin, Gaofei⁷  Wen, Jianguang⁴  Yang, Bin⁸  Zhu, Peng¹  Chen, Min² 

[1] CEA CNRS UVSQ, Lab Sci Climat & Environm, UMR8212, Gif Sur Yvette, France

[2] Pacific Northwest Natl Lab, Joint Global Change Res Inst, College Pk, MD 20740 USA

[3] Carnegie Inst Sci, Dept Global Ecol, Stanford, CA 94305 USA

[4] Chinese Acad Sci, Aerosp Informat Res Inst, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China

[5] Sun Yat Sen Univ, Guangdong Prov Key Lab Climate Change & Nat Disas, Sch Atmospher Sci, Guangzhou 510275, Peoples R China

[6] Univ Space Res Assoc, Columbia, MD 21046 USA

[7] Southwest Jiaotong Univ, Fac Geosci & Environm Engn, Chengdu 610031, Peoples R China

[8] Hunan Univ, Coll Elect & Informat Engn, Changsha 410082, Peoples R China

关键词: Leaf optical properties;    Leaf reflectance/transmittance;    Leaf functional traits;    Spectral invariants theory;    Photon recollision probability;   

DOI  :  10.1016/j.rse.2020.112131

来源: Elsevier

【 摘 要 】

Leaf optical spectra reflect the combination of leaf biochemical, morphological and physiological properties, and play an important role in many ecological and Earth system processes. Radiative transfer models are widely used to simulate leaf spectra by quantifying photon transfer processes of reflection, transmission and absorption within a plant leaf. Recent advances in spectral invariants theory offer a unique and efficient approach for modeling the canopy-scale radiative transfer processes, but remain underexplored for applications at the leaf scale. In this study, we developed a leaf-scale optical property model based on the spectrally invariant properties (leaf-SIP) of plant leaves. Similar to the canopy-scale model, the leaf-SIP model decouples leaf-scale radiative transfer process into two parts: wavelength-dependent contribution from leaf chemical components and wavelength-independent contribution from leaf structures, described by two spectrally invariant parameters (i.e., a photon recollision probability p and a scattering asymmetry parameter q). We implemented the leaf-SIP model by parameterizing p and q with a measurable leaf morphological trait, the leaf mass per area (LMA). We evaluated the performance of the leaf-SIP model with two in situ datasets (i.e., LOPEX and ANGERS) and the widely used PROSPECT leaf optical model. The results show that the leaf spectra simulated by the leaf-SIP model agreed well with in situ datasets and the simulations of the PROSPECT model, with a small root mean squared error (RMSE), bias, and high coefficients of determination (R-2) of 0.026, 0.035, 0.95 and 0.037, 0.049, 0.91 for leaf reflectance and leaf transmittance, respectively. Our results also show that the leaf-SIP model can be used with measured leaf spectra to accurately estimate several key leaf functional traits, such as the leaf chlorophyll content, equivalent water thickness, and LMA. The leaf-SIP model provides an efficient and physical way of accurately simulating leaf spectra and retrieving key leaf functional traits from hyperspectral measurements.

【 授权许可】

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