MODIS Collection 6.1 aerosol optical depth products over land and ocean: validation and comparison

Wei, Jing; Li, Zhanqing; Peng, Yiran; Sun, Lin

doi:10.1016/j.atmosenv.2018.12.004

Cited by 266 publications

(179 citation statements)

References 34 publications

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“…The statistical relation between RMB and aerosol loading (shown as red curves of decline trend) indicates that the overestimation was obvious with low aerosol loading. Referring to related studies, similar significant overestimation results with few successful retrievals and small proportion of retrievals falling within EE lines were also noted in Africa and other bare lands of the world (Farahat 2019;Wei, Li, et al, 2019). In contrast, the retrievals in Western China did not perform well, with R 2 being only 0.73 and the slope of the regression lines being 1.26, that is, much greater than 1.…”

Section: 1029/2019ea000809supporting

confidence: 76%

“…Sites with over 200 matches were mostly located in NCP, while PRD and Western China had less number of matches owing to the reduced quality assurance of retrievals in coastal pixels and problems pertaining to satellite AOD retrieval on snow-covered surfaces. Moreover, the verification experiments at the global scale showed that the monthly C6.1 DT AOD averages overestimated ground measurements by 25%, especially in Asia and western North America (Wei, Li, et al, 2019;. Nevertheless, most of matchups were distributed above the 1:1 reference line, resulting in an obvious overestimation, with an RMB of 1.41 and a high percentage of matchups above EE envelopes of 54%, which was greater than the percentage within EE envelopes (45%).…”

Section: Overall Performance Of C61 In Comparison To C6 Retrievals Omentioning

confidence: 88%

“…AERONET measurements have been used to validate and correct the bias of satellite AOD retrievals (Almazroui, 2019; Che et al, 2018;Qin et al, 2017), due to its consistent international standardization of instruments, rigorous calibration and processing, globally distributed sites, and convenient data access. In the paper, Level 2.0 of the AERONET Version 3.0 AOD data set was gathered from a total of 20 sites (Che et al, 2018;Eck et al, 2018;Wei, Li, et al, 2019). In the paper, Level 2.0 of the AERONET Version 3.0 AOD data set was gathered from a total of 20 sites (Che et al, 2018;Eck et al, 2018;Wei, Li, et al, 2019).…”

Section: Aerosol Robotic Network (Aeronet)mentioning

confidence: 99%

“…Bilal et al (2018) and Wei, Li, et al (2019), respectively evaluated the MODIS AOD products in the global scale to understand the overall performance of products in each continent. Bilal et al (2018) and Wei, Li, et al (2019), respectively evaluated the MODIS AOD products in the global scale to understand the overall performance of products in each continent.…”

Section: Overall Performance Of C61 In Comparison To C6 Retrievals Omentioning

confidence: 99%

“…However, China, a country with the largest population, is suffering from severe haze pollution due to increasing urbanization and economic growth. Previous studies evaluated and compared the performance of MODIS C6.1 and C6 AOD products against ground AERONET AOD measurements at global, national, regional, and city scales, considering ground elevation, season, and multifarious underlying surface types (Bilal et al, 2018;Tian et al, 2018;Wang et al, 2019;Wei, Li, et al, 2019;. It is important and necessary to conduct a detailed validation of the MODIS C6.1 DT aerosol product for China, where an aerosol varies greatly in horizontal and vertical dimensions because of the variations in terrain, complex climate affected by seasonal monsoon, and diverse aerosol sources (Cheng et al, 2016;Fan et al, 2019;Sheng et al, 2019;Sun et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Evaluation and Comparison of MODIS Collection 6.1 and Collection 6 Dark Target Aerosol Optical Depth over Mainland China Under Various Conditions Including Spatiotemporal Distribution, Haze Effects, and Underlying Surface

Huang

Zhu

et al. 2019

Earth and Space Science

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Modifications such as degrading the retrieval quality of mixed pixels in the coastline area and revising surface characterization scheme have been made to the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6.1 (C6.1) Dark Target (DT) aerosol optical depth (AOD) product to address inaccuracy over urban areas. In this study, comprehensive evaluations of modifications to the MODIS C6.1 DT AOD product, in comparison with Collection 6 (C6), are conducted over mainland China under different spatial distributions, seasons, and air quality for the period 2010-2017, combined with validation against Aerosol Robotic Network (AERONET) AOD measurements. The preliminary result showed that the C6.1 DT AOD product in China displayed an overall good performance with high R 2 (0.87) and low root-mean-square error (0.23) against ground measurements. Moreover, the C6.1 DT AOD product was an overall improvement over C6, with greater correlation and lower uncertainty against ground measurements, especially for the North China Plain and Central China, although this was not the case for Western China. The improvement was also seasonal, being distinct in spring but less pronounced in winter, and negatively correlated with the level of air pollution. Furthermore, the analysis of DT AOD retrievals in different urbanized areas illustrated that the updated DT algorithm worked well in completely urbanized areas, where 97% of C6.1 DT AOD retrievals were an improvement over C6, while approximately 10% of C6.1 DT AOD retrievals were deteriorated in semiurbanized areas. Additionally, the DT AOD retrievals in areas with relatively low enhanced vegetation index and high surface reflectance were significantly improved, mitigating problems associated with the DT algorithm, further improving the reliability of MODIS DT AOD products. Plain Language Summary Modifications have been made to the Moderate Resolution ImagingSpectroradiometer (MODIS) aerosol optical depth (AOD) product to address inaccuracy over urban areas. This study evaluates the MODIS AOD product in comparison with the old version. Specifically, we evaluated products' performance over mainland China under different spatial distributions, seasons, and air quality for the period 2010-2017. It was demonstrated that the updated AOD retrieval algorithm show a visible improvement in highly urbanized areas, as well as areas with relatively low enhanced vegetation index and high surface reflectance. However, because the surface reflectance scheme was trained over the continental United States, it could not effectively describe the complex surfaces in Eastern and Western China, and therefore, further improvement is required in this regard.

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Section: 1029/2019ea000809supporting

confidence: 76%

Section: Overall Performance Of C61 In Comparison To C6 Retrievals Omentioning

confidence: 88%

Section: Aerosol Robotic Network (Aeronet)mentioning

confidence: 99%

Section: Overall Performance Of C61 In Comparison To C6 Retrievals Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation and Comparison of MODIS Collection 6.1 and Collection 6 Dark Target Aerosol Optical Depth over Mainland China Under Various Conditions Including Spatiotemporal Distribution, Haze Effects, and Underlying Surface

Huang

Zhu

et al. 2019

Earth and Space Science

View full text Add to dashboard Cite

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The Role of Midlatitude Cyclones in the Emission, Transport, Production, and Removal of Aerosols in the Northern Hemisphere

Robinson

Jaeglé

Oman

2022

Preprint

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We examine the distribution of aerosol optical depth (AOD) across 27,707 northern hemisphere (NH) midlatitude cyclones for 2005-2018 using retrievals from the Moderate Resolution Spectroradiometer (MODIS) sensor on the Aqua satellite. Cyclonecentered composites show AOD enhancements of 20-45% relative to background conditions in the warm conveyor belt (WCB) airstream. Fine mode AOD (fAOD) accounts for 68% of this enhancement annually. Relative to background conditions, coarse mode AOD (cAOD) is enhanced by more than a factor of two near the center of the composite cyclone, co-located with high surface wind speeds. Within the WCB, MODIS AOD maximizes in spring, with a secondary maximum in summer. Cyclone-centered composites of AOD from the Modern Era Retrospective analysis for Research and Applications, version 2 Global Modeling Initiative (M2GMI) simulation reproduce the magnitude and seasonality of the MODIS AOD composites and enhancements. M2GMI simulations show that the AOD enhancement in the WCB is dominated by sulfate (37%) and organic aerosol (25%), with dust and sea salt each accounting for 15%. MODIS and M2GMI AOD are 60% larger in North Pacific WCBs compared to North Atlantic WCBs and show a strong relationship with anthropogenic pollution. We infer that NH midlatitude cyclones account for 355 Tg yr -1 of sea salt aerosol emissions annually, or 60% of the 30-80 o N total. We find that deposition within WCBs is responsible for up to 35% of the total aerosol deposition over the NH ocean basins. Furthermore, the cloudy environment of WCBs leads to efficient secondary sulfate production.

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Climatology of aerosol types and their vertical distribution over East Asia based on CALIPSO lidar measurements

Gui

Tao

Wang

et al. 2022

Intl Journal of Climatology

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Aerosol vertical distribution generally determines their health impacts and climate effects. By using long‐term (2007–2019) CALIPSO lidar measurements, we present a large‐scale insight into the climatology of aerosol types and their vertical structure over East Asia. Despite the low sampling frequency, comparison with MODIS aerosol optical depth (AOD) shows that the integrated CAIPSO vertical extinction can reasonably reproduce spatial patterns of the aerosol loading. With the unique advantage of active detection, CALIPSO reveals an obvious enhancement of the night‐time AOD due to worse diffusion conditions. Moreover, long‐range transport of different aerosols including dust, polluted dust, and smoke has substantial contribution to the aerosol loading over East Asia. Pure dust particles are mainly concentrated over the deserts with notable dust transport belts (dust AOD > 0.2 at 532 nm) along downwind regions during winter and spring. By contrast, polluted dust is prevalent over the downstream eastern China with much higher AODs throughout the year. In particular, AOD of polluted dust (~0.5) is higher in winter rather than in spring, which is consistent with their seasonal occurrences. Smoke aerosols usually appear in the night‐time over southern China. The top heights of aerosols are around 4–6 km, with dust and smoke having higher extinction at upstream regions. The climatology of these aerosol types and vertical distribution can provide a significant constraint for associated studies of air quality and climate effects.

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MODIS Collection 6.1 aerosol optical depth products over land and ocean: validation and comparison

Cited by 266 publications

References 34 publications

Evaluation and Comparison of MODIS Collection 6.1 and Collection 6 Dark Target Aerosol Optical Depth over Mainland China Under Various Conditions Including Spatiotemporal Distribution, Haze Effects, and Underlying Surface

Evaluation and Comparison of MODIS Collection 6.1 and Collection 6 Dark Target Aerosol Optical Depth over Mainland China Under Various Conditions Including Spatiotemporal Distribution, Haze Effects, and Underlying Surface

The Role of Midlatitude Cyclones in the Emission, Transport, Production, and Removal of Aerosols in the Northern Hemisphere

Climatology of aerosol types and their vertical distribution over East Asia based on CALIPSO lidar measurements

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