A Comprehensive Description of Multi-Term LSM for Applying Multiple a Priori Constraints in Problems of Atmospheric Remote Sensing: GRASP Algorithm, Concept, and Applications

Frontiers in Remote Sensing, Journal Year: 2021, Volume and Issue: 2

Published: Oct. 19, 2021

Advanced inversion Multi-term approach utilizing multiple a priori constraints is proposed. The used as base for the first unified algorithm GRASP that applicable to diverse remote sensing observations and retrieving variety of atmospheric properties. utilization demonstrated.

Language: Английский

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Evaluation of MERRA-2 Aerosol Optical and Component Properties over China Using SONET and PARASOL/GRASP Data

Remote Sensing, Journal Year: 2022, Volume and Issue: 14(4), P. 821 - 821

Published: Feb. 9, 2022

The Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) is widely used as an advanced model dataset the understanding of global climate change. However, independent validation comparison MERRA-2 are both insufficient always desired. Therefore, in this study, quantitative evaluation aerosol products was conducted over China Aerosol Optical Depth (AOD), Angstrom exponent (AE), absorbing AOD (AAOD) chemical components (black carbon (BC) dust (DU)) using Sun sky radiometer Observation NETwork (SONET) ground-based measurements POLDER-3/PARASOL satellite generated by GRASP algorithm. available monthly PARASOL/GRASP seasonal were intercompared China. (550 nm) show general good agreement with SONET PARASOL/GRASP. For example, correlation coefficients usually 0.6–0.85 0.75–0.85 PARASOL/GRASP, bias −0.293 to +0.008 SONET. AE AAOD, still reasonable. found overestimate fine mode display a underestimation absorption In addition, BC DU mass concentrations spatial consistency climatological products. relatively high columnar concentration observed around 1.5–2 mg/m3 East industrial region 150 near Taklimakan desert. shows slightly higher lower than evaluations situ surface verify overestimation (MAE = +0.44 µg/m2) −0.38 demonstrates multi-source datasets, such ground-based, space-borne remote sensing, measurements, simulation well reanalysis data, complement each other can be refine characterization.

Language: Английский

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Validation and diurnal variation evaluation of MERRA-2 multiple aerosol properties on a global scale

Atmospheric Environment, Journal Year: 2023, Volume and Issue: 311, P. 120019 - 120019

Published: Aug. 10, 2023

Language: Английский

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Algorithm evaluation for polarimetric remote sensing of atmospheric aerosols

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(5), P. 1497 - 1525

Published: March 12, 2024

Abstract. From a passive satellite remote sensing point of view, the richest set information on aerosol properties can be obtained from instruments that measure both intensity and polarization backscattered sunlight at multiple wavelengths viewing angles for one ground pixel. However, it is challenging to exploit this global scale because complex algorithms are needed with many fit parameters (aerosol land/ocean reflection), based online radiative transfer models. So far, two such have demonstrated capability scale: Generalized Retrieval Atmosphere Surface Properties (GRASP) algorithm Remote Trace gas Aerosol Products (RemoTAP) algorithm. In paper, we present detailed comparison most recent versions RemoTAP GRASP. We evaluate synthetic observations, real PARASOL (Polarization Anisotropy Reflectances Atmospheric Science coupled Observations Lidar) observations against AERONET (Aerosol Robotic Network) common pixels, retrievals year 2008. For optical depth (AOD) over land, show root mean square error (RMSE) 0.10 (at 550 nm). single scattering albedo (SSA), good performance in terms RMSE (0.04), but has smaller bias (0.002) compared GRASP (0.021). Ångström exponent (AE), (0.367) than (0.387), mainly caused by small overestimate AE low values (large particles). Over ocean perform very well. AOD, an 0.057 even 0.047. AE, RMSEs 0.285 0.224, respectively. Based comparison, conclude similar overall performance, where stronger weaker points. data products, find difference (RMSD) between AOD 0.12 0.038 land ocean, The largest differences occur biomass burning region equatorial Africa. virtually unbiased respect each other. RMSD 0.33 0.23 ocean. SSA, much better agreement (bias = −0.01, 0.043 > 0.2) 0.053, 0.074). As expected, increase towards also products MODIS. either or MODIS worse themselves. among three AOD. latest product other improved significantly previous version RemoTAP. results demonstrate dedicated effort development multi-angle polarimetric (MAP) still leads substantial improvement resulting ongoing process.

Language: Английский

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Retrieval of total and fine mode aerosol optical depth by an improved MODIS Dark Target algorithm

Environment International, Journal Year: 2022, Volume and Issue: 166, P. 107343 - 107343

Published: June 11, 2022

Total and fine mode aerosol optical depth (AODT AODF), as well the fraction (FMF = AODF/AODT), are critical variables for climate change atmospheric environment studies. The retrievals with high accuracy from satellite observations, particularly FMF AODF over land, remain challenging. This study aims to improve Moderate-resolution Imaging Spectro-radiometer (MODIS) land dark target (DT) algorithm retrieving AODT, AODF, on a global scale. Based fact that underestimated surface reflectance (SR) could overestimate AODT underestimate size parameter in DT algorithm, two robust schemes were developed SR determination: first (NEW1 DT) used top of atmosphere instead at 2.12 µm; second (NEW2 eleven-year MODIS data establish monthly spectral relationship model (2.12-0.47 2.12-0.65 µm) database pixel-by-pixel Then novel lookup table approach based physical process was proposed retrieve FMF. new FMF, compared AERosol RObotic NETwork (AERONET) retrievals. Results showed root mean square error (RMSE) 0.096-0.103, 0.098-0.099, 0.167-0.180 AODTs, AODFs, FMFs, respectively, which better than Collection 6.1 (C6.1) (0.117, 0.235, 0.426) validation by AERONET sites. From results, NEW2 provided coarse AOD retrievals, while NEW1 had performances. spatial patterns AODC algorithms comparable those Polarization Directionality Earth's Reflectances product. Hence, have potential provide products scientific community using long-term data.

Language: Английский

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Climatology of aerosol component concentrations derived from multi-angular polarimetric POLDER-3 observations using GRASP algorithm

Earth system science data, Journal Year: 2022, Volume and Issue: 14(7), P. 3439 - 3469

Published: July 29, 2022

Abstract. The study presents a climatology of aerosol composition concentrations obtained by recently developed algorithm approach, namely the Generalized Retrieval Atmosphere and Surface Properties (GRASP)/Component. It is applied to whole archive observations from POLarization Directionality Earth's Reflectances (POLDER-3). conceptual specifics GRASP/Component approach in direct retrieval speciation (component fraction) without intermediate retrievals optical characteristics. Although global validation derived component product challenging, results are line with general knowledge about types different regions. In addition, we compare GRASP-derived black carbon (BC) dust components those Modern-Era Retrospective Analysis for Research Applications, version 2 (MERRA-2) product. Quite reasonable agreement was found between spatial temporal distribution species provided GRASP MERRA-2. differences, however, appeared regions known strong biomass burning emissions; reasons discrepancies discussed. other components, such as absorbing (BC, brown (BrC), iron-oxide content mineral dust) scattering (ammonium sulfate nitrate, organic carbon, non-absorbing aerosols, represent scarce but imperative information potential adjustment chemical transport models. properties (e.g., depth (AOD), Ångström exponent (AE), single-scattering albedo (SSA), fine- coarse-mode (AODF AND AODC)) were agree well Aerosol Robotic Network (AERONET) ground reference data, fully consistent previous Optimized, High Precision (HP) Models versions POLDER-3 data. Thus, presented extensive provides an opportunity understanding variabilities trends regional distributions species. addition additional valuable, qualitatively new insight and, therefore, demonstrates advantages multi-angular polarimetric (MAP) satellite next frontier inversion advanced observations. satellite-based dataset expected be useful improving emissions component-resolved radiative forcing estimations. products publicly available (https://www.grasp-open.com/products/, last access: 15 March 2022) used current registered under https://doi.org/10.5281/zenodo.6395384 (Li et al., 2022b).

Language: Английский

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A Two-Stage Machine Learning Algorithm for Retrieving Multiple Aerosol Properties Over Land: Development and Validation

IEEE Transactions on Geoscience and Remote Sensing, Journal Year: 2023, Volume and Issue: 61, P. 1 - 17

Published: Jan. 1, 2023

Satellite-based aerosol optical property retrieval over land, especially size-related parameters, is challenging. This study proposed a novel two-stage machine learning (ML) algorithm for retrieving depth (AOD), Ångström exponent (AE), fine mode fraction (FMF), and AOD (FAOD)) land using MODIS observed reflectance. The new ML consists of three steps: (1) first, all samples extracted from AERONET measurements were used to train the model, (2) then, reduce extreme estimation bias divided low-value high-value models, respectively, (3) finally, models integrated into final based on weight interpolation. Independent site network validation results show that has Pearson correlation coefficient (R) 0.894 (0.638, 0.661, 0.865) root mean square error (RMSE) 0.146 (0.258, 0.245, 0.153) (AE, FMF, FAOD) retrieval, which significantly outperforms metrics operational products, with RMSE 0.130-0.156 (0.536-0.569, 0.313, 0.191). inter-comparison products shows spatial patterns AOD, AE, FAOD are in good agreement those POLDER products. These illustrate performance transferability indicate ability methods be applied multispectral instruments (such as MODIS) retrieve multiple properties.

Language: Английский

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A robust and flexible satellite aerosol retrieval algorithm for multi-angle polarimetric measurements with physics-informed deep learning method

Remote Sensing of Environment, Journal Year: 2023, Volume and Issue: 297, P. 113763 - 113763

Published: Aug. 23, 2023

Language: Английский

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Towards long-term, high-accuracy, and continuous satellite total and fine-mode aerosol records: Enhanced Land General Aerosol (e-LaGA) retrieval algorithm for VIIRS

ISPRS Journal of Photogrammetry and Remote Sensing, Journal Year: 2024, Volume and Issue: 214, P. 261 - 281

Published: July 1, 2024

Language: Английский

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Fengyun 4A Land Aerosol Retrieval: Algorithm Development, Validation, and Comparison With Other Datasets

IEEE Transactions on Geoscience and Remote Sensing, Journal Year: 2023, Volume and Issue: 61, P. 1 - 16

Published: Jan. 1, 2023

The Advanced Geostationary Radiation Imager (AGRI) onboard the Fengyun 4A (FY-4A) satellite has high spatiotemporal resolution and provides useful spectral information that can be used to monitor aerosols air pollution. objective of this study is propose Land General Aerosol (LaGA) algorithm for retrieving aerosol using AGRI data in Asia region. First, sensitivity analysis indicated blue band more suitable retrieval, its red sensitive under loading. Then, a real-time surface reflectance (SR) database was established atmosphere-corrected technique based on background AOD library regional model parameters. By comparing observed with calculated lookup table, optical depth (AOD) 1-h obtained. validation results AOD, both at all moments (data volume: 12,102) daily mean 1,766), exhibit good agreement AERONET (R > 0.830). Its performance comparable MOdIs dark target (DT) (expected error (EE), ± (0.05 + 20%τ _AERONET ): = 0.673 vs. DT 0.666) Himawari-8 (H8) (EE: 0.698 H8 0.658). pixel-by-pixel comparison demonstrated R between MODIS AODs >0.6, bias them within ±0.05 most area. These suggest robustness proposed algorithm, it great potential application follow-up 4 series satellites.

Language: Английский

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