Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective

Solar radiation (SR) is a critical environmental factor influencing plant ecophysiology and ecosystem dynamics, not merely as an energy source but through its spectral characteristics, including critical wavelength ratios (CWRs) that trigger photomorphogenic responses in plants, the diffuse fraction...

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Main Authors: Amila Nuwan Siriwardana, Atsushi Kume
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Ecological Informatics
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Online Access:http://www.sciencedirect.com/science/article/pii/S1574954124004825
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author Amila Nuwan Siriwardana
Atsushi Kume
author_facet Amila Nuwan Siriwardana
Atsushi Kume
author_sort Amila Nuwan Siriwardana
collection DOAJ
description Solar radiation (SR) is a critical environmental factor influencing plant ecophysiology and ecosystem dynamics, not merely as an energy source but through its spectral characteristics, including critical wavelength ratios (CWRs) that trigger photomorphogenic responses in plants, the diffuse fraction (DF), that affect light distribution within canopies, and the variability of SR. This study presents the Spectral Characteristics Index (SCI), a novel method that integrates spectral quality and energy flux to classify daily SR conditions.Data were collected using a rotating shadow-band spectroradiometer. The study applied agglomerative hierarchical clustering (AHC) based on cumulative Euclidean distance matrices and identified five SR clusters ranging from clear (SCI-01) to overcast (SCI-05) conditions, with spectral shifts from red to blue. Significant differences in DF, global solar irradiance (GSI), and CWRs were observed across clusters (p < 0.0001, F > 27).Given the challenges in obtaining comprehensive spectral data in certain regions, machine learning models replicated SCI clustering using easily accessible environmental variables (DF, GSI, variability, airmass, and vapor pressure). The support vector machine (SVM) model achieved 88.03 % validation accuracy and 94.29 % test accuracy, providing a practical alternative where spectral measurements are not available. While long-term data collection across various climatic zones could improve the validity and adaptability of SCIs to different geographical locations, the current model demonstrates high accuracy and efficiency. This innovative approach enhances the understanding of SR dynamics and advances ecological research on plant responses and ecosystem functions.
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spelling doaj-art-770b1b147ff74931a0e2eb194cff97f12025-01-19T06:24:36ZengElsevierEcological Informatics1574-95412025-03-0185102940Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspectiveAmila Nuwan Siriwardana0Atsushi Kume1Faculty of Agriculture, Kyushu University, 744 mottooka, Nishi-ku, Fukuoka 819-0395, JapanCorresponding author.; Faculty of Agriculture, Kyushu University, 744 mottooka, Nishi-ku, Fukuoka 819-0395, JapanSolar radiation (SR) is a critical environmental factor influencing plant ecophysiology and ecosystem dynamics, not merely as an energy source but through its spectral characteristics, including critical wavelength ratios (CWRs) that trigger photomorphogenic responses in plants, the diffuse fraction (DF), that affect light distribution within canopies, and the variability of SR. This study presents the Spectral Characteristics Index (SCI), a novel method that integrates spectral quality and energy flux to classify daily SR conditions.Data were collected using a rotating shadow-band spectroradiometer. The study applied agglomerative hierarchical clustering (AHC) based on cumulative Euclidean distance matrices and identified five SR clusters ranging from clear (SCI-01) to overcast (SCI-05) conditions, with spectral shifts from red to blue. Significant differences in DF, global solar irradiance (GSI), and CWRs were observed across clusters (p < 0.0001, F > 27).Given the challenges in obtaining comprehensive spectral data in certain regions, machine learning models replicated SCI clustering using easily accessible environmental variables (DF, GSI, variability, airmass, and vapor pressure). The support vector machine (SVM) model achieved 88.03 % validation accuracy and 94.29 % test accuracy, providing a practical alternative where spectral measurements are not available. While long-term data collection across various climatic zones could improve the validity and adaptability of SCIs to different geographical locations, the current model demonstrates high accuracy and efficiency. This innovative approach enhances the understanding of SR dynamics and advances ecological research on plant responses and ecosystem functions.http://www.sciencedirect.com/science/article/pii/S1574954124004825Solar radiation clusteringDiffuse radiationMachine learningSpectral distributionSpectral characteristics index
spellingShingle Amila Nuwan Siriwardana
Atsushi Kume
Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective
Ecological Informatics
Solar radiation clustering
Diffuse radiation
Machine learning
Spectral distribution
Spectral characteristics index
title Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective
title_full Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective
title_fullStr Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective
title_full_unstemmed Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective
title_short Introducing the spectral characteristics index: A novel method for clustering solar radiation fluctuations from a plant-ecophysiological perspective
title_sort introducing the spectral characteristics index a novel method for clustering solar radiation fluctuations from a plant ecophysiological perspective
topic Solar radiation clustering
Diffuse radiation
Machine learning
Spectral distribution
Spectral characteristics index
url http://www.sciencedirect.com/science/article/pii/S1574954124004825
work_keys_str_mv AT amilanuwansiriwardana introducingthespectralcharacteristicsindexanovelmethodforclusteringsolarradiationfluctuationsfromaplantecophysiologicalperspective
AT atsushikume introducingthespectralcharacteristicsindexanovelmethodforclusteringsolarradiationfluctuationsfromaplantecophysiologicalperspective