Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years

In this study, the global land surface albedo namely GAC43 was retrieved for the years 1979 to 2020 using Advanced Very High Resolution Radiometer (AVHRR) global area coverage (GAC) data onboard National Oceanic and Atmospheric Administration (NOAA) and Meteorological Operational (MetOp) satellites....

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Main Authors: Shaopeng Li, Xiongxin Xiao, Christoph Neuhaus, Stefan Wunderle
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Remote Sensing
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Online Access:https://www.mdpi.com/2072-4292/17/1/117
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author Shaopeng Li
Xiongxin Xiao
Christoph Neuhaus
Stefan Wunderle
author_facet Shaopeng Li
Xiongxin Xiao
Christoph Neuhaus
Stefan Wunderle
author_sort Shaopeng Li
collection DOAJ
description In this study, the global land surface albedo namely GAC43 was retrieved for the years 1979 to 2020 using Advanced Very High Resolution Radiometer (AVHRR) global area coverage (GAC) data onboard National Oceanic and Atmospheric Administration (NOAA) and Meteorological Operational (MetOp) satellites. We provide a comprehensive retrieval process of the GAC43 albedo, followed by a comprehensive assessment against in situ measurements and three widely used satellite-based albedo products, the third edition of the CM SAF cLoud, Albedo and surface RAdiation (CLARA-A3), the Copernicus Climate Change Service (C3S) albedo product, and MODIS BRDF/albedo product (MCD43). Our quantitative evaluations indicate that GAC43 demonstrates the best stability, with a linear trend of ±0.002 per decade at nearly all pseudo invariant calibration sites (PICS) from 1982 to 2020. In contrast, CLARA-A3 exhibits significant noise before the 2000s due to the limited availability of observations, while C3S shows substantial biases during the same period due to imperfect sensors intercalibrations. Extensive validation at globally distributed homogeneous sites shows that GAC43 has comparable accuracy to C3S, with an overall RMSE of approximately 0.03, but a smaller positive bias of 0.012. Comparatively, MCD43C3 shows the lowest RMSE (~0.023) and minimal bias, while CLARA-A3 displays the highest RMSE (~0.042) and bias (0.02). Furthermore, GAC43, CLARA-A3, and C3S exhibit overestimation in forests, with positive biases exceeding 0.023 and RMSEs of at least 0.028. In contrast, MCD43C3 shows negligible bias and a smaller RMSE of 0.015. For grasslands and shrublands, GAC43 and MCD43C3 demonstrate comparable estimation uncertainties of approximately 0.023, with close positive biases near 0.09, whereas C3S and CLARA-A3 exhibit higher RMSEs and biases exceeding 0.032 and 0.022, respectively. All four albedo products show significant RMSEs around 0.035 over croplands but achieve the highest estimation accuracy better than 0.020 over deserts. It is worth noting that significant biases are typically attributed to insufficient spatial representativeness of the measurement sites. Globally, GAC43 and C3S exhibit similar spatial distribution patterns across most land surface conditions, including an overestimation compared to MCD43C3 and an underestimation compared to CLARA-A3 in forested areas. In addition, GAC43, C3S, and CLARA-A3 estimate higher albedo values than MCD43C3 in low-vegetation regions, such as croplands, grasslands, savannas, and woody savannas. Besides the fact that the new GAC43 product shows the best stability covering the last 40 years, one has to consider the higher proportion of backup inversions before 2000. Overall, GAC43 offers a promising long-term and consistent albedo with good accuracy for future studies such as global climate change, energy balance, and land management policy.
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spelling doaj-art-3dec4361934c4bee8da1de73accea2412025-01-10T13:20:17ZengMDPI AGRemote Sensing2072-42922025-01-0117111710.3390/rs17010117Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 YearsShaopeng Li0Xiongxin Xiao1Christoph Neuhaus2Stefan Wunderle3Institute of Geography, University of Bern, CH-3012 Bern, SwitzerlandInstitute of Geography, University of Bern, CH-3012 Bern, SwitzerlandInstitute of Geography, University of Bern, CH-3012 Bern, SwitzerlandInstitute of Geography, University of Bern, CH-3012 Bern, SwitzerlandIn this study, the global land surface albedo namely GAC43 was retrieved for the years 1979 to 2020 using Advanced Very High Resolution Radiometer (AVHRR) global area coverage (GAC) data onboard National Oceanic and Atmospheric Administration (NOAA) and Meteorological Operational (MetOp) satellites. We provide a comprehensive retrieval process of the GAC43 albedo, followed by a comprehensive assessment against in situ measurements and three widely used satellite-based albedo products, the third edition of the CM SAF cLoud, Albedo and surface RAdiation (CLARA-A3), the Copernicus Climate Change Service (C3S) albedo product, and MODIS BRDF/albedo product (MCD43). Our quantitative evaluations indicate that GAC43 demonstrates the best stability, with a linear trend of ±0.002 per decade at nearly all pseudo invariant calibration sites (PICS) from 1982 to 2020. In contrast, CLARA-A3 exhibits significant noise before the 2000s due to the limited availability of observations, while C3S shows substantial biases during the same period due to imperfect sensors intercalibrations. Extensive validation at globally distributed homogeneous sites shows that GAC43 has comparable accuracy to C3S, with an overall RMSE of approximately 0.03, but a smaller positive bias of 0.012. Comparatively, MCD43C3 shows the lowest RMSE (~0.023) and minimal bias, while CLARA-A3 displays the highest RMSE (~0.042) and bias (0.02). Furthermore, GAC43, CLARA-A3, and C3S exhibit overestimation in forests, with positive biases exceeding 0.023 and RMSEs of at least 0.028. In contrast, MCD43C3 shows negligible bias and a smaller RMSE of 0.015. For grasslands and shrublands, GAC43 and MCD43C3 demonstrate comparable estimation uncertainties of approximately 0.023, with close positive biases near 0.09, whereas C3S and CLARA-A3 exhibit higher RMSEs and biases exceeding 0.032 and 0.022, respectively. All four albedo products show significant RMSEs around 0.035 over croplands but achieve the highest estimation accuracy better than 0.020 over deserts. It is worth noting that significant biases are typically attributed to insufficient spatial representativeness of the measurement sites. Globally, GAC43 and C3S exhibit similar spatial distribution patterns across most land surface conditions, including an overestimation compared to MCD43C3 and an underestimation compared to CLARA-A3 in forested areas. In addition, GAC43, C3S, and CLARA-A3 estimate higher albedo values than MCD43C3 in low-vegetation regions, such as croplands, grasslands, savannas, and woody savannas. Besides the fact that the new GAC43 product shows the best stability covering the last 40 years, one has to consider the higher proportion of backup inversions before 2000. Overall, GAC43 offers a promising long-term and consistent albedo with good accuracy for future studies such as global climate change, energy balance, and land management policy.https://www.mdpi.com/2072-4292/17/1/117albedoBRDFAVHRRretrievalevaluation
spellingShingle Shaopeng Li
Xiongxin Xiao
Christoph Neuhaus
Stefan Wunderle
Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years
Remote Sensing
albedo
BRDF
AVHRR
retrieval
evaluation
title Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years
title_full Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years
title_fullStr Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years
title_full_unstemmed Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years
title_short Retrieval and Evaluation of Global Surface Albedo Based on AVHRR GAC Data of the Last 40 Years
title_sort retrieval and evaluation of global surface albedo based on avhrr gac data of the last 40 years
topic albedo
BRDF
AVHRR
retrieval
evaluation
url https://www.mdpi.com/2072-4292/17/1/117
work_keys_str_mv AT shaopengli retrievalandevaluationofglobalsurfacealbedobasedonavhrrgacdataofthelast40years
AT xiongxinxiao retrievalandevaluationofglobalsurfacealbedobasedonavhrrgacdataofthelast40years
AT christophneuhaus retrievalandevaluationofglobalsurfacealbedobasedonavhrrgacdataofthelast40years
AT stefanwunderle retrievalandevaluationofglobalsurfacealbedobasedonavhrrgacdataofthelast40years