Sungchan Jeong , Youngryel Ryu , Xing Li , Benjamin Dechant , Jiangong Liu , Juwon Kong , Wonseok Choi , Jianing Fang , Xu Lian , Pierre Gentine
{"title":"GEOSIF: A continental-scale sub-daily reconstructed solar-induced fluorescence derived from OCO-3 and GK-2A over Eastern Asia and Oceania","authors":"Sungchan Jeong , Youngryel Ryu , Xing Li , Benjamin Dechant , Jiangong Liu , Juwon Kong , Wonseok Choi , Jianing Fang , Xu Lian , Pierre Gentine","doi":"10.1016/j.rse.2024.114284","DOIUrl":null,"url":null,"abstract":"<div><p>The diurnal solar-induced chlorophyll fluorescence (SIF) sampling capability of OCO-3 can provide crucial insights into ecosystem function at the sub-daily scale. However, potential applications of OCO-3 SIF have suffered from its inherent spatiotemporal discontinuity. In this study, we addressed the discontinuous observation coverage of OCO-3 SIF by utilizing information coming from the continuous geostationary satellite observations from Geostationary Korea Multi-Purpose Satellite-2A (GK-2A). We generated and comprehensively evaluated a continental-scale hourly reconstructed SIF over the Eastern Asia and Oceania. To do this, we trained an extreme gradient boosting (XGBoost) model using OCO-3 SIF and GK-2A observations including four band Nadir BRDF Adjusted Reflectance (NBAR) (blue, green, red, and near-infrared), shortwave radiation, and vapor pressure deficit (VPD) using the data from August 2019 to July 2021. The reconstructed SIF data showed robust agreement with OCO-3 SIF across diverse ecosystems, different hours of the day, and varying observation geometries (R<sup>2</sup> = 0.68–79). We found large feature importance of near-infrared reflectance, red reflectance, and shortwave radiation, which together explained 84.6% of SIF prediction. VPD played an increasing role under high temperature conditions. The reconstructed SIF effectively captured the afternoon depression of photosynthesis across diverse ecosystems, ranging from 63.9% to 88.9%, which was consistent with the original OCO-3 SIF. Our results identified a more pronounced afternoon depression in the physiological SIF yield than in the canopy structural proxy. In addition, diurnal changes in both canopy structural and physiological components of SIF showed a stronger relationship with VPD than that of temperature. These findings highlight the benefits of the synergistic use of new-generation satellite observations to improve our understanding of large-scale diurnal ecosystem dynamics and its environmental drivers.</p></div>","PeriodicalId":417,"journal":{"name":"Remote Sensing of Environment","volume":null,"pages":null},"PeriodicalIF":11.1000,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Remote Sensing of Environment","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S003442572400302X","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
The diurnal solar-induced chlorophyll fluorescence (SIF) sampling capability of OCO-3 can provide crucial insights into ecosystem function at the sub-daily scale. However, potential applications of OCO-3 SIF have suffered from its inherent spatiotemporal discontinuity. In this study, we addressed the discontinuous observation coverage of OCO-3 SIF by utilizing information coming from the continuous geostationary satellite observations from Geostationary Korea Multi-Purpose Satellite-2A (GK-2A). We generated and comprehensively evaluated a continental-scale hourly reconstructed SIF over the Eastern Asia and Oceania. To do this, we trained an extreme gradient boosting (XGBoost) model using OCO-3 SIF and GK-2A observations including four band Nadir BRDF Adjusted Reflectance (NBAR) (blue, green, red, and near-infrared), shortwave radiation, and vapor pressure deficit (VPD) using the data from August 2019 to July 2021. The reconstructed SIF data showed robust agreement with OCO-3 SIF across diverse ecosystems, different hours of the day, and varying observation geometries (R2 = 0.68–79). We found large feature importance of near-infrared reflectance, red reflectance, and shortwave radiation, which together explained 84.6% of SIF prediction. VPD played an increasing role under high temperature conditions. The reconstructed SIF effectively captured the afternoon depression of photosynthesis across diverse ecosystems, ranging from 63.9% to 88.9%, which was consistent with the original OCO-3 SIF. Our results identified a more pronounced afternoon depression in the physiological SIF yield than in the canopy structural proxy. In addition, diurnal changes in both canopy structural and physiological components of SIF showed a stronger relationship with VPD than that of temperature. These findings highlight the benefits of the synergistic use of new-generation satellite observations to improve our understanding of large-scale diurnal ecosystem dynamics and its environmental drivers.
期刊介绍:
Remote Sensing of Environment (RSE) serves the Earth observation community by disseminating results on the theory, science, applications, and technology that contribute to advancing the field of remote sensing. With a thoroughly interdisciplinary approach, RSE encompasses terrestrial, oceanic, and atmospheric sensing.
The journal emphasizes biophysical and quantitative approaches to remote sensing at local to global scales, covering a diverse range of applications and techniques.
RSE serves as a vital platform for the exchange of knowledge and advancements in the dynamic field of remote sensing.