Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach

Solar-induced chlorophyll fluorescence (SIF), as a direct indicator of vegetation photosynthesis, offers a more accurate measure of plant photosynthetic dynamics than traditional vegetation indices. However, the current SIF satellite products have low spatial resolution, limiting their application i...

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Main Authors: Jinrui Fan, Xiaoping Lu, Guosheng Cai, Zhengfang Lou, Jing Wen
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/1/133
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author Jinrui Fan
Xiaoping Lu
Guosheng Cai
Zhengfang Lou
Jing Wen
author_facet Jinrui Fan
Xiaoping Lu
Guosheng Cai
Zhengfang Lou
Jing Wen
author_sort Jinrui Fan
collection DOAJ
description Solar-induced chlorophyll fluorescence (SIF), as a direct indicator of vegetation photosynthesis, offers a more accurate measure of plant photosynthetic dynamics than traditional vegetation indices. However, the current SIF satellite products have low spatial resolution, limiting their application in fine-scale agricultural research. To address this, we leveraged MODIS data at a 1 km resolution, including bands b1, b2, b3, and b4, alongside indices such as the NDVI, EVI, NIRv, OSAVI, SAVI, LAI, FPAR, and LST, covering October 2018 to May 2020 for Shandong Province, China. Using the Random Forest (RF) model, we downscaled SIF data from 0.05° to 1 km based on invariant spatial scaling theory, focusing on the winter wheat growth cycle. Various machine learning models, including CNN, Stacking, Extreme Random Trees, AdaBoost, and GBDT, were compared, with Random Forest yielding the best performance, achieving R<sup>2</sup> = 0.931, RMSE = 0.052 mW/m<sup>2</sup>/nm/sr, and MAE = 0.031 mW/m<sup>2</sup>/nm/sr for 2018–2019 and R<sup>2</sup> = 0.926, RMSE = 0.058 mW/m<sup>2</sup>/nm/sr, and MAE = 0.034 mW/m<sup>2</sup>/nm/sr for 2019–2020. The downscaled SIF products showed a strong correlation with TanSIF and GOSIF products (R<sup>2</sup> > 0.8), and consistent trends with GPP further confirmed the reliability of the 1 km SIF product. Additionally, a time series analysis of Shandong Province’s wheat-growing areas revealed a strong correlation (R<sup>2</sup> > 0.8) between SIF and multiple vegetation indices, underscoring its utility for regional crop monitoring.
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spelling doaj-art-e223e61194fc48939cabf4b25efc86b52025-01-24T13:16:52ZengMDPI AGAgronomy2073-43952025-01-0115113310.3390/agronomy15010133Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence ApproachJinrui Fan0Xiaoping Lu1Guosheng Cai2Zhengfang Lou3Jing Wen4Key Laboratory of Spatio-Temporal Information and Ecological Restoration of Mines, Ministry of Natural Resources of the People’s Republic of China, Henan Polytechnic University, Jiaozuo 454000, ChinaKey Laboratory of Spatio-Temporal Information and Ecological Restoration of Mines, Ministry of Natural Resources of the People’s Republic of China, Henan Polytechnic University, Jiaozuo 454000, ChinaKey Laboratory of Spatio-Temporal Information and Ecological Restoration of Mines, Ministry of Natural Resources of the People’s Republic of China, Henan Polytechnic University, Jiaozuo 454000, ChinaKey Laboratory of Spatio-Temporal Information and Ecological Restoration of Mines, Ministry of Natural Resources of the People’s Republic of China, Henan Polytechnic University, Jiaozuo 454000, ChinaKey Laboratory of Spatio-Temporal Information and Ecological Restoration of Mines, Ministry of Natural Resources of the People’s Republic of China, Henan Polytechnic University, Jiaozuo 454000, ChinaSolar-induced chlorophyll fluorescence (SIF), as a direct indicator of vegetation photosynthesis, offers a more accurate measure of plant photosynthetic dynamics than traditional vegetation indices. However, the current SIF satellite products have low spatial resolution, limiting their application in fine-scale agricultural research. To address this, we leveraged MODIS data at a 1 km resolution, including bands b1, b2, b3, and b4, alongside indices such as the NDVI, EVI, NIRv, OSAVI, SAVI, LAI, FPAR, and LST, covering October 2018 to May 2020 for Shandong Province, China. Using the Random Forest (RF) model, we downscaled SIF data from 0.05° to 1 km based on invariant spatial scaling theory, focusing on the winter wheat growth cycle. Various machine learning models, including CNN, Stacking, Extreme Random Trees, AdaBoost, and GBDT, were compared, with Random Forest yielding the best performance, achieving R<sup>2</sup> = 0.931, RMSE = 0.052 mW/m<sup>2</sup>/nm/sr, and MAE = 0.031 mW/m<sup>2</sup>/nm/sr for 2018–2019 and R<sup>2</sup> = 0.926, RMSE = 0.058 mW/m<sup>2</sup>/nm/sr, and MAE = 0.034 mW/m<sup>2</sup>/nm/sr for 2019–2020. The downscaled SIF products showed a strong correlation with TanSIF and GOSIF products (R<sup>2</sup> > 0.8), and consistent trends with GPP further confirmed the reliability of the 1 km SIF product. Additionally, a time series analysis of Shandong Province’s wheat-growing areas revealed a strong correlation (R<sup>2</sup> > 0.8) between SIF and multiple vegetation indices, underscoring its utility for regional crop monitoring.https://www.mdpi.com/2073-4395/15/1/133solar-induced chlorophyll fluorescencerandom forestdownscalinggross primary productivitywheat growth analysis
spellingShingle Jinrui Fan
Xiaoping Lu
Guosheng Cai
Zhengfang Lou
Jing Wen
Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach
Agronomy
solar-induced chlorophyll fluorescence
random forest
downscaling
gross primary productivity
wheat growth analysis
title Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach
title_full Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach
title_fullStr Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach
title_full_unstemmed Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach
title_short Multi-Feature Driver Variable Fusion Downscaling TROPOMI Solar-Induced Chlorophyll Fluorescence Approach
title_sort multi feature driver variable fusion downscaling tropomi solar induced chlorophyll fluorescence approach
topic solar-induced chlorophyll fluorescence
random forest
downscaling
gross primary productivity
wheat growth analysis
url https://www.mdpi.com/2073-4395/15/1/133
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AT xiaopinglu multifeaturedrivervariablefusiondownscalingtropomisolarinducedchlorophyllfluorescenceapproach
AT guoshengcai multifeaturedrivervariablefusiondownscalingtropomisolarinducedchlorophyllfluorescenceapproach
AT zhengfanglou multifeaturedrivervariablefusiondownscalingtropomisolarinducedchlorophyllfluorescenceapproach
AT jingwen multifeaturedrivervariablefusiondownscalingtropomisolarinducedchlorophyllfluorescenceapproach