SO<sub>2</sub> emissions derived from TROPOMI observations over India using a flux-divergence method with variable lifetimes
<p>The rapid development of the economy and the implementation of environmental policies adapted in India have led to fast changes of regional SO<span class="inline-formula"><sub>2</sub></span> emissions. We present a monthly SO<span class="inline-form...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/25/1851/2025/acp-25-1851-2025.pdf |
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| Summary: | <p>The rapid development of the economy and the implementation of environmental policies adapted in India have led to fast changes of regional SO<span class="inline-formula"><sub>2</sub></span> emissions. We present a monthly SO<span class="inline-formula"><sub>2</sub></span> emission inventory for India covering December 2018 to November 2023 based on the Tropospheric Monitoring Instrument (TROPOMI) Level-2 COBRA SO<span class="inline-formula"><sub>2</sub></span> dataset, using an improved flux-divergence method and estimated local SO<span class="inline-formula"><sub>2</sub></span> lifetime, which includes both its chemical loss and dry deposition. We update the methodology to use the daily CAMS model output estimates of the hydroxyl-radical distribution as well as the measured dry deposition velocity to account for the variability in the tropospheric SO<span class="inline-formula"><sub>2</sub></span> lifetime. It is the first effort to derive the local SO<span class="inline-formula"><sub>2</sub></span> lifetime for application in the divergence method. The results show the application of the local SO<span class="inline-formula"><sub>2</sub></span> lifetime improves the accuracy of SO<span class="inline-formula"><sub>2</sub></span> emissions estimation when compared to calculations using a constant lifetime. Our improved flux-divergence method reduced the spreading of the point-source emissions compared to the standard flux-divergence method. Our derived averaged SO<span class="inline-formula"><sub>2</sub></span> emissions covering the recent 5 years are about 5.2 Tg yr<span class="inline-formula"><sup>−1</sup></span> with a monthly mean uncertainty of 40 %, which is lower than the bottom-up emissions of 11.0 Tg yr<span class="inline-formula"><sup>−1</sup></span> from CAMS-GLOB-ANT v5.3. The total emissions from the 92 largest point-source emissions are estimated to be 2.9 Tg yr<span class="inline-formula"><sup>−1</sup></span>, lower than the estimation of 5.2 Tg yr<span class="inline-formula"><sup>−1</sup></span> from the global SO<span class="inline-formula"><sub>2</sub></span> catalog MSAQSO<span class="inline-formula"><sub>2</sub></span>LV4. We claim that the variability in the SO<span class="inline-formula"><sub>2</sub></span> lifetime is important to account for in estimating top-down SO<span class="inline-formula"><sub>2</sub></span> emissions.</p> |
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| ISSN: | 1680-7316 1680-7324 |