Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions
Satellite-based monitoring of atmospheric column-averaged dry-air mole fraction (XCH<sub>4</sub>) is essential for quantifying methane (CH<sub>4</sub>) emissions, yet uncharacterized spatially varying biases in XCH<sub>4</sub> observations can cause misattribution...
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MDPI AG
2025-07-01
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| author | Sihong Zhu Dongxu Yang Liang Feng Longfei Tian Yi Liu Junji Cao Minqiang Zhou Zhaonan Cai Kai Wu Paul I. Palmer |
| author_facet | Sihong Zhu Dongxu Yang Liang Feng Longfei Tian Yi Liu Junji Cao Minqiang Zhou Zhaonan Cai Kai Wu Paul I. Palmer |
| author_sort | Sihong Zhu |
| collection | DOAJ |
| description | Satellite-based monitoring of atmospheric column-averaged dry-air mole fraction (XCH<sub>4</sub>) is essential for quantifying methane (CH<sub>4</sub>) emissions, yet uncharacterized spatially varying biases in XCH<sub>4</sub> observations can cause misattribution in flux estimates. This study assesses the potential of the upcoming TanSat-2 satellite mission to estimate China’s CH<sub>4</sub> emission using a series of Observing System Simulation Experiments (OSSEs) based on an Ensemble Kalman Filter (EnKF) inversion framework coupled with GEOS-Chem on a 0.5° × 0.625° grid, alongside an evaluation of current TROPOMI-based products against Total Carbon Column Observing Network (TCCON) observations. Assuming a target precision of 8 ppb, TanSat-2 could achieve an annual national emission estimate accuracy of 2.9% ± 4.2%, reducing prior uncertainty by 84%, with regional deviations below 5.0% across Northeast, Central, East, and Southwest China. In contrast, limited coverage in South China due to persistent cloud cover leads to a 26.1% discrepancy—also evident in <i>pseudo</i> TROPOMI OSSEs—highlighting the need for complementary ground-based monitoring strategies. Sensitivity analyses show that satellite retrieval biases strongly affect inversion robustness, reducing the accuracy in China’s total emission estimates by 5.8% for every 1 ppb increase in bias level across scenarios, particularly in Northeast, Central and East China. We recommend expanding ground-based XCH<sub>4</sub> observations in these regions to support the correction of satellite-derived biases and improve the reliability of satellite-constrained inversion results. |
| format | Article |
| id | doaj-art-e206a254f7ee42548f9dd8b4e2271c02 |
| institution | OA Journals |
| issn | 2072-4292 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj-art-e206a254f7ee42548f9dd8b4e2271c022025-08-20T02:36:27ZengMDPI AGRemote Sensing2072-42922025-07-011713232110.3390/rs17132321Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> EmissionsSihong Zhu0Dongxu Yang1Liang Feng2Longfei Tian3Yi Liu4Junji Cao5Minqiang Zhou6Zhaonan Cai7Kai Wu8Paul I. Palmer9Carbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaCarbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaSchool of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UKInnovation Academy for Microsatellites, Chinese Academy of Sciences, Shanghai 201306, ChinaCarbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaUniversity of Chinese Academy of Sciences, Beijing 100049, ChinaCarbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaCarbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaCarbon Neutrality Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, ChinaSchool of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UKSatellite-based monitoring of atmospheric column-averaged dry-air mole fraction (XCH<sub>4</sub>) is essential for quantifying methane (CH<sub>4</sub>) emissions, yet uncharacterized spatially varying biases in XCH<sub>4</sub> observations can cause misattribution in flux estimates. This study assesses the potential of the upcoming TanSat-2 satellite mission to estimate China’s CH<sub>4</sub> emission using a series of Observing System Simulation Experiments (OSSEs) based on an Ensemble Kalman Filter (EnKF) inversion framework coupled with GEOS-Chem on a 0.5° × 0.625° grid, alongside an evaluation of current TROPOMI-based products against Total Carbon Column Observing Network (TCCON) observations. Assuming a target precision of 8 ppb, TanSat-2 could achieve an annual national emission estimate accuracy of 2.9% ± 4.2%, reducing prior uncertainty by 84%, with regional deviations below 5.0% across Northeast, Central, East, and Southwest China. In contrast, limited coverage in South China due to persistent cloud cover leads to a 26.1% discrepancy—also evident in <i>pseudo</i> TROPOMI OSSEs—highlighting the need for complementary ground-based monitoring strategies. Sensitivity analyses show that satellite retrieval biases strongly affect inversion robustness, reducing the accuracy in China’s total emission estimates by 5.8% for every 1 ppb increase in bias level across scenarios, particularly in Northeast, Central and East China. We recommend expanding ground-based XCH<sub>4</sub> observations in these regions to support the correction of satellite-derived biases and improve the reliability of satellite-constrained inversion results.https://www.mdpi.com/2072-4292/17/13/2321TanSat-2methane emission inversionOSSEs |
| spellingShingle | Sihong Zhu Dongxu Yang Liang Feng Longfei Tian Yi Liu Junji Cao Minqiang Zhou Zhaonan Cai Kai Wu Paul I. Palmer Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions Remote Sensing TanSat-2 methane emission inversion OSSEs |
| title | Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions |
| title_full | Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions |
| title_fullStr | Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions |
| title_full_unstemmed | Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions |
| title_short | Theoretical Potential of TanSat-2 to Quantify China’s CH<sub>4</sub> Emissions |
| title_sort | theoretical potential of tansat 2 to quantify china s ch sub 4 sub emissions |
| topic | TanSat-2 methane emission inversion OSSEs |
| url | https://www.mdpi.com/2072-4292/17/13/2321 |
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