The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China
Due to the significant spatial variation of the performance of Moderate Resolution Imaging Spectrometer (MODIS) aerosol optical depth (AOD) retrievals, validation is very important for applications of MODIS AOD products at regional scales. This study presents a comparative analysis of Collection 6.1...
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ftdoajarticles:oai:doaj.org/article:e9fcdb778d9d4e45b3d68791e130355d 2023-05-15T13:07:02+02:00 The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China Kun Sun Yang Gao Bing Qi Zhifeng Yu 2022-02-01T00:00:00Z https://doi.org/10.3390/rs14040938 https://doaj.org/article/e9fcdb778d9d4e45b3d68791e130355d EN eng MDPI AG https://www.mdpi.com/2072-4292/14/4/938 https://doaj.org/toc/2072-4292 doi:10.3390/rs14040938 2072-4292 https://doaj.org/article/e9fcdb778d9d4e45b3d68791e130355d Remote Sensing, Vol 14, Iss 938, p 938 (2022) Yangtze River Delta aerosol optical depth validation MODIS sun photometer land cover Science Q article 2022 ftdoajarticles https://doi.org/10.3390/rs14040938 2022-12-31T15:46:14Z Due to the significant spatial variation of the performance of Moderate Resolution Imaging Spectrometer (MODIS) aerosol optical depth (AOD) retrievals, validation is very important for applications of MODIS AOD products at regional scales. This study presents a comparative analysis of Collection 6.1 MODIS AOD retrievals and ground measurements from five local sites and one Aerosol Robotic Network (AERONET) site in the Yangtze River Delta (YRD) region, which significantly complements the previous validation that utilized limited AERONET measurements. Generally, MODIS AOD retrievals showed a reasonable agreement with collocated ground measurements (R 2 > 0.7), with 66% of Dark Target (DT) 10 km retrievals, 56% of Deep Blue (DB) 10 km retrievals, and 69% of DT 3 km retrievals falling within the expected error (EE = ±(0.05 + 0.2 × AOD)). Nevertheless, it was found that the DT AOD retrievals tended to be overestimated over urbanized and lakeside sites, while the DB AOD retrievals tended to be underestimated over all ground sites except for lakeside sites. Such patterns appeared to be linked with the systematic biases of the single-scattering albedo estimation in the AOD retrieval algorithms. Another significant finding of this study is that the uncertainties of the MODIS AOD retrievals were highly correlated with the land cover proportions of urbanized features and water (LCP_UW) in the surrounding region, especially for the DT products. An empirical correction method based on these correlations could substantially reduce the uncertainties of DT AOD products over high LCP_UW areas. The results not only highlight the significant impacts of both urban and water areas on the MODIS AOD retrieval algorithms but also create new possibilities to correct such impacts once the universal correlations between LCP_UW and the uncertainty measures are established. Article in Journal/Newspaper Aerosol Robotic Network Directory of Open Access Journals: DOAJ Articles Remote Sensing 14 4 938 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Yangtze River Delta aerosol optical depth validation MODIS sun photometer land cover Science Q |
spellingShingle |
Yangtze River Delta aerosol optical depth validation MODIS sun photometer land cover Science Q Kun Sun Yang Gao Bing Qi Zhifeng Yu The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China |
topic_facet |
Yangtze River Delta aerosol optical depth validation MODIS sun photometer land cover Science Q |
description |
Due to the significant spatial variation of the performance of Moderate Resolution Imaging Spectrometer (MODIS) aerosol optical depth (AOD) retrievals, validation is very important for applications of MODIS AOD products at regional scales. This study presents a comparative analysis of Collection 6.1 MODIS AOD retrievals and ground measurements from five local sites and one Aerosol Robotic Network (AERONET) site in the Yangtze River Delta (YRD) region, which significantly complements the previous validation that utilized limited AERONET measurements. Generally, MODIS AOD retrievals showed a reasonable agreement with collocated ground measurements (R 2 > 0.7), with 66% of Dark Target (DT) 10 km retrievals, 56% of Deep Blue (DB) 10 km retrievals, and 69% of DT 3 km retrievals falling within the expected error (EE = ±(0.05 + 0.2 × AOD)). Nevertheless, it was found that the DT AOD retrievals tended to be overestimated over urbanized and lakeside sites, while the DB AOD retrievals tended to be underestimated over all ground sites except for lakeside sites. Such patterns appeared to be linked with the systematic biases of the single-scattering albedo estimation in the AOD retrieval algorithms. Another significant finding of this study is that the uncertainties of the MODIS AOD retrievals were highly correlated with the land cover proportions of urbanized features and water (LCP_UW) in the surrounding region, especially for the DT products. An empirical correction method based on these correlations could substantially reduce the uncertainties of DT AOD products over high LCP_UW areas. The results not only highlight the significant impacts of both urban and water areas on the MODIS AOD retrieval algorithms but also create new possibilities to correct such impacts once the universal correlations between LCP_UW and the uncertainty measures are established. |
format |
Article in Journal/Newspaper |
author |
Kun Sun Yang Gao Bing Qi Zhifeng Yu |
author_facet |
Kun Sun Yang Gao Bing Qi Zhifeng Yu |
author_sort |
Kun Sun |
title |
The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China |
title_short |
The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China |
title_full |
The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China |
title_fullStr |
The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China |
title_full_unstemmed |
The Influence of Underlying Land Cover on the Accuracy of MODIS C6.1 Aerosol Products—A Case Study over the Yangtze River Delta Region of China |
title_sort |
influence of underlying land cover on the accuracy of modis c6.1 aerosol products—a case study over the yangtze river delta region of china |
publisher |
MDPI AG |
publishDate |
2022 |
url |
https://doi.org/10.3390/rs14040938 https://doaj.org/article/e9fcdb778d9d4e45b3d68791e130355d |
genre |
Aerosol Robotic Network |
genre_facet |
Aerosol Robotic Network |
op_source |
Remote Sensing, Vol 14, Iss 938, p 938 (2022) |
op_relation |
https://www.mdpi.com/2072-4292/14/4/938 https://doaj.org/toc/2072-4292 doi:10.3390/rs14040938 2072-4292 https://doaj.org/article/e9fcdb778d9d4e45b3d68791e130355d |
op_doi |
https://doi.org/10.3390/rs14040938 |
container_title |
Remote Sensing |
container_volume |
14 |
container_issue |
4 |
container_start_page |
938 |
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1766032385273495552 |