An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO
The verification and correction of CALIPSO aerosol products is key to understanding the atmospheric environment and climate change. However, CALIPSO often cannot detect the full profile of aerosol for the low instrument sensitivity near the surface. Thus, a correction scheme for the aerosol extincti...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/16/3085 |
| _version_ | 1797522238956634112 |
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| author | Zhaoliang Zeng Zemin Wang Baojun Zhang |
| author_facet | Zhaoliang Zeng Zemin Wang Baojun Zhang |
| author_sort | Zhaoliang Zeng |
| collection | DOAJ |
| description | The verification and correction of CALIPSO aerosol products is key to understanding the atmospheric environment and climate change. However, CALIPSO often cannot detect the full profile of aerosol for the low instrument sensitivity near the surface. Thus, a correction scheme for the aerosol extinction coefficient (AECs) in the planetary boundary layer (PBL) is proposed to improve the quality of the CALIPSO-based aerosol optical depth (AOD) at 532 nm. This scheme assumed that the aerosol is vertically and uniformly distributed below the PBL, and that the AECs in the whole PBL are equal to those at the top of the PBL; then, the CALIPSO AOD was obtained by vertically integrating AECs throughout the whole atmosphere. Additionally, the CALIPSO AOD and corrected CALIPSO AOD were validated against seven ground-based sites across eastern China during 2007–2015. Our results show that the initial CALIPSO AOD obtained by cloud filtering was generally lower than that of the ground-based observations. After accounting for the AECs in the PBL, the adjustment method tended to improve the CALIPSO AOD data quality. The average <i>R</i> (slope) value from all sites was improved by 7% (46%). Further, the relative distance between the ground track of CALIPSO and the ground station exhibited an influence on the validation result of CALIPSO AOD. The retrieval precision of CALIPSO AOD worsened with the increase in water vapor in the atmosphere. Our findings indicate that our scheme significantly improves the accuracy of CALIPSO AOD, which will help to provide alternative AOD products in the presence of severe atmospheric pollution. |
| first_indexed | 2024-03-10T08:25:35Z |
| format | Article |
| id | doaj.art-9c7d1e64b26e462f9b5ccb4281d54ceb |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T08:25:35Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-9c7d1e64b26e462f9b5ccb4281d54ceb2023-11-22T09:31:35ZengMDPI AGRemote Sensing2072-42922021-08-011316308510.3390/rs13163085An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSOZhaoliang Zeng0Zemin Wang1Baojun Zhang2Chinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan 430079, ChinaChinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan 430079, ChinaChinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan 430079, ChinaThe verification and correction of CALIPSO aerosol products is key to understanding the atmospheric environment and climate change. However, CALIPSO often cannot detect the full profile of aerosol for the low instrument sensitivity near the surface. Thus, a correction scheme for the aerosol extinction coefficient (AECs) in the planetary boundary layer (PBL) is proposed to improve the quality of the CALIPSO-based aerosol optical depth (AOD) at 532 nm. This scheme assumed that the aerosol is vertically and uniformly distributed below the PBL, and that the AECs in the whole PBL are equal to those at the top of the PBL; then, the CALIPSO AOD was obtained by vertically integrating AECs throughout the whole atmosphere. Additionally, the CALIPSO AOD and corrected CALIPSO AOD were validated against seven ground-based sites across eastern China during 2007–2015. Our results show that the initial CALIPSO AOD obtained by cloud filtering was generally lower than that of the ground-based observations. After accounting for the AECs in the PBL, the adjustment method tended to improve the CALIPSO AOD data quality. The average <i>R</i> (slope) value from all sites was improved by 7% (46%). Further, the relative distance between the ground track of CALIPSO and the ground station exhibited an influence on the validation result of CALIPSO AOD. The retrieval precision of CALIPSO AOD worsened with the increase in water vapor in the atmosphere. Our findings indicate that our scheme significantly improves the accuracy of CALIPSO AOD, which will help to provide alternative AOD products in the presence of severe atmospheric pollution.https://www.mdpi.com/2072-4292/13/16/3085CALIPSOaerosol optical depthcorrectionplanetary boundary layer |
| spellingShingle | Zhaoliang Zeng Zemin Wang Baojun Zhang An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO Remote Sensing CALIPSO aerosol optical depth correction planetary boundary layer |
| title | An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO |
| title_full | An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO |
| title_fullStr | An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO |
| title_full_unstemmed | An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO |
| title_short | An Adjustment Approach for Aerosol Optical Depth Inferred from CALIPSO |
| title_sort | adjustment approach for aerosol optical depth inferred from calipso |
| topic | CALIPSO aerosol optical depth correction planetary boundary layer |
| url | https://www.mdpi.com/2072-4292/13/16/3085 |
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