Intercomparison of CH[sub.4] Products in China from GOSAT, TROPOMI, IASI, and AIRS Satellites

Methane (CH[sub.4]) is an important greenhouse as well as a chemically active gas. Accurate monitoring and understanding of its spatiotemporal distribution are crucial for effective mitigation strategies. Nowadays, satellite measurements are widely used for CH[sub.4] studies. Here, we use the CH[sub...

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Bibliographic Details
Published in:Remote sensing (Basel, Switzerland) Switzerland), 2023-09, Vol.15 (18)
Main Authors: Ni, Qichen, Zhou, Minqiang, Wang, Jiaxin, Wang, Ting, Wang, Gengchen, Wang, Pucai
Format: Article
Language:English
Subjects:
Emissions (Pollution)
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Summary:Methane (CH[sub.4]) is an important greenhouse as well as a chemically active gas. Accurate monitoring and understanding of its spatiotemporal distribution are crucial for effective mitigation strategies. Nowadays, satellite measurements are widely used for CH[sub.4] studies. Here, we use the CH[sub.4] products from four commonly used satellites (GOSAT, TROPOMI, ARIS, and IASI) during the period from 2018 to 2020 to investigate the spatiotemporal variations of CH[sub.4] in China. In spite of the same target (CH[sub.4]) for the four satellites, differences among them exist in terms of the instrument, spectrum, and retrieval algorithm. The GOSAT and TROPOMI CH[sub.4] retrievals use shortwave infrared spectra, with a better sensitivity near the surface, while the IASI and AIRS CH[sub.4] retrievals use thermal infrared spectra, showing a good sensitivity in the mid–upper troposphere but a weak sensitivity in the lower troposphere. The GOSAT and TROPOMI observe high CH[sub.4] concentrations in the east and south and low concentrations in the west and north, which is highly related to the CH[sub.4] emissions. The IASI and AIRS show a more uniform CH[sub.4] distribution over China, which reflects the variation of CH[sub.4] at a high altitude. However, a large discrepancy is observed between the IASI and AIRS despite using a similar retrieval band, e.g., significant differences in the seasonal variations of CH[sub.4] are observed between the IASI and AIRS across several regions in China. This study highlights the CH[sub.4] differences observed by the four satellites in China, and caution must be taken when using these satellite products.
ISSN:2072-4292
2072-4292
DOI:10.3390/rs15184499