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Xia C, Liu C, Cai Z, Duan X, Hu Q, Zhao F, Liu H, Ji X, Zhang C, Liu Y. Improved Anthropogenic SO 2 Retrieval from High-Spatial-Resolution Satellite and its Application during the COVID-19 Pandemic. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:11538-11548. [PMID: 34488351 DOI: 10.1021/acs.est.1c01970] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Sulfur dioxide (SO2) measured by satellites is widely used to estimate anthropogenic emissions. The Sentinel-5 Precursor (S-5P) operational SO2 product is overestimated compared to the ground-based multiaxis differential optical absorption spectroscopy (MAX-DOAS) measurements in China and shows an opposite variation to the surface measurements, which limits the application of TROPOspheric monitoring instrument (TROPOMI) products in emissions research. Radiometric calibration, a priori profiles, and fitting windows might cause the overestimation of S-5P operational SO2 product. Here, we improve the optimal-estimation-based algorithm through several calibration methods. The improved retrieval agrees reasonably well with the ground-based measurements (R > 0.70, bias <13.7%) and has smaller biases (-28.9%) with surface measurements over China and India. It revealed that the SO2 column in March 2020 decreased by 51.6% compared to March 2019 due to the lockdown for curbing the spread of the COVID-19 pandemic, and there was a decrease of 50% during the lockdown than those after the lockdown, similar to the surface measurement trend, while S-5P operational SO2 product showed an unrealistic increase of 19%. In India, the improved retrieval identified obvious "hot spots" and observed a 30% decrease of SO2 columns during the lockdown.
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Affiliation(s)
- Congzi Xia
- School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Cheng Liu
- Key Lab of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
- Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- School of Engineering Science, University of Science and Technology of China, Hefei 230026, China
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230026, China
| | - Zhaonan Cai
- Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing 100029, China
| | - Xiaonan Duan
- Bureau of Frontier Sciences and Education, Chinese Academy of Sciences, Beijing 100864, China
| | - Qihou Hu
- Key Lab of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Fei Zhao
- School of Engineering Science, University of Science and Technology of China, Hefei 230026, China
| | - Haoran Liu
- Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Xiangguang Ji
- Key Lab of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei 230026, China
| | - Chengxin Zhang
- School of Engineering Science, University of Science and Technology of China, Hefei 230026, China
| | - Yi Liu
- Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing 100029, China
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