Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES
The Global Change Observation Mission-Climate (GCOM-C) satellite, launched in December 2017, is equipped with the Second-generation Global Imager (SGLI) sensor, featuring a moderate spatial resolution of 250 m and 19 spectral bands, including the unique 380 nm band. After six years in orbit, a compr...
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2025-01-01
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| author | Salem Ibrahim Salem Mitsuhiro Toratani Hiroto Higa SeungHyun Son Eko Siswanto Joji Ishizaka |
| author_facet | Salem Ibrahim Salem Mitsuhiro Toratani Hiroto Higa SeungHyun Son Eko Siswanto Joji Ishizaka |
| author_sort | Salem Ibrahim Salem |
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| description | The Global Change Observation Mission-Climate (GCOM-C) satellite, launched in December 2017, is equipped with the Second-generation Global Imager (SGLI) sensor, featuring a moderate spatial resolution of 250 m and 19 spectral bands, including the unique 380 nm band. After six years in orbit, a comprehensive evaluation of SGLI products and their temporal consistency is needed. Remote sensing reflectance (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula>) is the primary product for monitoring water quality, forming the basis for deriving key oceanic constituents such as chlorophyll-a (Chla) and total suspended matter (TSM). The Japan Aerospace Exploration Agency (JAXA) provides <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products through two platforms, G-Portal and JASMES, each employing different atmospheric correction methodologies and assumptions. This study aims to evaluate the SGLI full-resolution <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products from G-Portal and JASMES at regional scales (Japan and East Asia) and assess G-Portal <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products globally between January 2018 and December 2023. The evaluation employs in situ matchups from NASA’s Aerosol Robotic Network-Ocean Color (AERONET-OC) and cruise measurements. We also assess the retrieval accuracy of two water quality indices, Chla and TSM. The AERONET-OC data analysis reveals that JASMES systematically underestimates <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> values at shorter wavelengths, particularly at 412 nm. While the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> accuracy at 412 nm is relatively low, G-Portal’s <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products perform better than JASMES at shorter wavelengths, showing lower errors and stronger correlations with AERONET-OC data. Both G-Portal and JASMES show lower agreement with AERONET-OC and cruise datasets at shorter wavelengths but demonstrate improved agreement at longer wavelengths (530 nm, 565 nm, and 670 nm). JASMES generates approximately 12% more matchup data points than G-Portal, likely due to G-Portal’s stricter atmospheric correction thresholds that exclude pixels with high reflectance. In situ measurements indicate that G-Portal provides better overall agreement, particularly at lower <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> magnitudes and Chla concentrations below 5 mg/m<sup>3</sup>. This evaluation underscores the complexities and challenges of atmospheric correction, particularly in optically complex coastal waters (Case 2 waters), which may require tailored atmospheric correction methods different from the standard approach. The assessment of temporal consistency and seasonal variations in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> data shows that both platforms effectively capture interannual trends and maintain temporal stability, particularly from the 490 nm band onward, underscoring the potential of SGLI data for long-term monitoring of coastal and oceanic environments. |
| format | Article |
| id | doaj-art-c241e13f9321413b97b191afd39fd372 |
| institution | Kabale University |
| issn | 2072-4292 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj-art-c241e13f9321413b97b191afd39fd3722025-01-24T13:47:47ZengMDPI AGRemote Sensing2072-42922025-01-0117222110.3390/rs17020221Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMESSalem Ibrahim Salem0Mitsuhiro Toratani1Hiroto Higa2SeungHyun Son3Eko Siswanto4Joji Ishizaka5Faculty of Engineering, Kyoto University of Advanced Science, 18 Yamanouchi Gotanda-cho, Ukyo-ku, Kyoto 615-8577, JapanSchool of Architecture and Urban Planning, Tokai University, Kitakaname, Hiratsuka 259-1292, JapanInstitute of Urban Innovation, Yokohama National University, Hodogaya, Yokohama 240-8501, JapanNOAA/NESDIS Center for Satellite Applications and Research, College Park, MD 20740, USAEarth Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Showa-machi 3173-25, Yokohama 2360001, JapanInstitute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-860, JapanThe Global Change Observation Mission-Climate (GCOM-C) satellite, launched in December 2017, is equipped with the Second-generation Global Imager (SGLI) sensor, featuring a moderate spatial resolution of 250 m and 19 spectral bands, including the unique 380 nm band. After six years in orbit, a comprehensive evaluation of SGLI products and their temporal consistency is needed. Remote sensing reflectance (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula>) is the primary product for monitoring water quality, forming the basis for deriving key oceanic constituents such as chlorophyll-a (Chla) and total suspended matter (TSM). The Japan Aerospace Exploration Agency (JAXA) provides <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products through two platforms, G-Portal and JASMES, each employing different atmospheric correction methodologies and assumptions. This study aims to evaluate the SGLI full-resolution <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products from G-Portal and JASMES at regional scales (Japan and East Asia) and assess G-Portal <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products globally between January 2018 and December 2023. The evaluation employs in situ matchups from NASA’s Aerosol Robotic Network-Ocean Color (AERONET-OC) and cruise measurements. We also assess the retrieval accuracy of two water quality indices, Chla and TSM. The AERONET-OC data analysis reveals that JASMES systematically underestimates <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> values at shorter wavelengths, particularly at 412 nm. While the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> accuracy at 412 nm is relatively low, G-Portal’s <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> products perform better than JASMES at shorter wavelengths, showing lower errors and stronger correlations with AERONET-OC data. Both G-Portal and JASMES show lower agreement with AERONET-OC and cruise datasets at shorter wavelengths but demonstrate improved agreement at longer wavelengths (530 nm, 565 nm, and 670 nm). JASMES generates approximately 12% more matchup data points than G-Portal, likely due to G-Portal’s stricter atmospheric correction thresholds that exclude pixels with high reflectance. In situ measurements indicate that G-Portal provides better overall agreement, particularly at lower <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> magnitudes and Chla concentrations below 5 mg/m<sup>3</sup>. This evaluation underscores the complexities and challenges of atmospheric correction, particularly in optically complex coastal waters (Case 2 waters), which may require tailored atmospheric correction methods different from the standard approach. The assessment of temporal consistency and seasonal variations in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>R</mi></mrow><mrow><mi>r</mi><mi>s</mi></mrow></msub></mrow></semantics></math></inline-formula> data shows that both platforms effectively capture interannual trends and maintain temporal stability, particularly from the 490 nm band onward, underscoring the potential of SGLI data for long-term monitoring of coastal and oceanic environments.https://www.mdpi.com/2072-4292/17/2/221AERONETatmospheric correctioncalibrationGCOM-CNASA SeaBASSocean color |
| spellingShingle | Salem Ibrahim Salem Mitsuhiro Toratani Hiroto Higa SeungHyun Son Eko Siswanto Joji Ishizaka Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES Remote Sensing AERONET atmospheric correction calibration GCOM-C NASA SeaBASS ocean color |
| title | Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES |
| title_full | Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES |
| title_fullStr | Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES |
| title_full_unstemmed | Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES |
| title_short | Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES |
| title_sort | long term evaluation of gcom c sgli reflectance and water quality products variability among jaxa g portal and jasmes |
| topic | AERONET atmospheric correction calibration GCOM-C NASA SeaBASS ocean color |
| url | https://www.mdpi.com/2072-4292/17/2/221 |
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