Articles | Volume 19, issue 11
https://doi.org/10.5194/gmd-19-4835-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/gmd-19-4835-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Development and technical paper
| 
10 Jun 2026
Development and technical paper |
| 10 Jun 2026
| 10 Jun 2026
OIRF-LEnKF v1.0: a novel data assimilation system by integrating incremental machine learning with a localized EnKF for enhanced PM2.5 chemical component simulation and reanalysis
Hongyi Li
State Key Laboratory of Atmospheric Environment and Extreme Meteorology, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
State Key Laboratory of Atmospheric Environment and Extreme Meteorology, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
State Key Laboratory of Atmospheric Environment and Extreme Meteorology, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
Di Zhang
China National Environmental Monitoring Centre, Beijing, China
Guigang Tang
China National Environmental Monitoring Centre, Beijing, China
Xiao Tang
State Key Laboratory of Atmospheric Environment and Extreme Meteorology, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
Zifa Wang
State Key Laboratory of Atmospheric Environment and Extreme Meteorology, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Revised manuscript not accepted
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We developed a quantitative decoupling analysis (QDA) method to quantify the contributions of emissions, meteorology, chemical reactions, and their nonlinear interactions on PM2.5. We found the effects of adverse meteorological conditions and the importance of nonlinear interactions. This method can provide valuable information for understanding of key factors to heavy pollution, but also help the modelers to find out the sources of uncertainties in numerical models.
Shujun Zhong, Shuang Chen, Junjun Deng, Yanbing Fan, Qiang Zhang, Qiaorong Xie, Yulin Qi, Wei Hu, Libin Wu, Xiaodong Li, Chandra Mouli Pavuluri, Jialei Zhu, Xin Wang, Di Liu, Xiaole Pan, Yele Sun, Zifa Wang, Yisheng Xu, Haijie Tong, Hang Su, Yafang Cheng, Kimitaka Kawamura, and Pingqing Fu
Atmos. Chem. Phys., 23, 2061–2077, https://doi.org/10.5194/acp-23-2061-2023, https://doi.org/10.5194/acp-23-2061-2023, 2023
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This study investigated the role of the secondary organic aerosol (SOA) loading on the molecular composition of wintertime urban aerosols by ultrahigh-resolution mass spectrometry. Results demonstrate that the SOA loading is an important factor associated with the oxidation degree, nitrate group content, and chemodiversity of nitrooxy–organosulfates. Our study also found that the hydrolysis of nitrooxy–organosulfates is a possible pathway for the formation of organosulfates.
Futing Wang, Ting Yang, Zifa Wang, Haibo Wang, Xi Chen, Yele Sun, Jianjun Li, Guigang Tang, and Wenxuan Chai
Atmos. Meas. Tech., 15, 6127–6144, https://doi.org/10.5194/amt-15-6127-2022, https://doi.org/10.5194/amt-15-6127-2022, 2022
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We develop a new algorithm to get the vertical mass concentration profiles of fine aerosol components based on the synergy of ground-based remote sensing for the first time. The comparisons with in situ observations and chemistry transport models validate the performance of the algorithm. Uncertainties caused by input parameters are also assessed in this paper. We expected that the algorithm can provide a new idea for lidar inversion and promote the development of aerosol component profiles.
Lichao Yang, Wansuo Duan, Zifa Wang, and Wenyi Yang
Atmos. Chem. Phys., 22, 11429–11453, https://doi.org/10.5194/acp-22-11429-2022, https://doi.org/10.5194/acp-22-11429-2022, 2022
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The initial meteorological state has a great impact on PM2.5 forecasts. Assimilating additional observations is an effective way to improve the accuracy of the initial meteorological state. Here we used an advanced optimization approach to identify where we should preferentially place the meteorological observations associated with PM2.5 forecasts in the Beijing–Tianjin–Hebei region of China. We provide evidence that the target observation strategy is effective for improving PM2.5 forecasts.
Zhiqiang Zhang, Yele Sun, Chun Chen, Bo You, Aodong Du, Weiqi Xu, Yan Li, Zhijie Li, Lu Lei, Wei Zhou, Jiaxing Sun, Yanmei Qiu, Lianfang Wei, Pingqing Fu, and Zifa Wang
Atmos. Chem. Phys., 22, 10409–10423, https://doi.org/10.5194/acp-22-10409-2022, https://doi.org/10.5194/acp-22-10409-2022, 2022
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We present a comprehensive characterization of water-soluble organic aerosol and the first mass spectral characterization of water-insoluble organic aerosol in the cold season in Beijing by integrating online and offline aerosol mass spectrometer measurements. WSOA comprised dominantly secondary OA and showed large changes during the transition season from autumn to winter. WIOA was characterized by prominent hydrocarbon ions series, low oxidation states, and significant day–night differences.
Jiaxing Sun, Yele Sun, Conghui Xie, Weiqi Xu, Chun Chen, Zhe Wang, Lei Li, Xubing Du, Fugui Huang, Yan Li, Zhijie Li, Xiaole Pan, Nan Ma, Wanyun Xu, Pingqing Fu, and Zifa Wang
Atmos. Chem. Phys., 22, 7619–7630, https://doi.org/10.5194/acp-22-7619-2022, https://doi.org/10.5194/acp-22-7619-2022, 2022
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We analyzed the chemical composition and mixing state of BC-containing particles at urban and rural sites in winter in the North China Plain and evaluated their impact on light absorption enhancement. BC was dominantly mixed with organic carbon, nitrate, and sulfate, and the mixing state evolved significantly as a function of relative humidity (RH) at both sites. The absorption enhancement depended strongly on coated secondary inorganic aerosol and was up to ~1.3–1.4 during aging processes.
Junjun Deng, Hao Ma, Xinfeng Wang, Shujun Zhong, Zhimin Zhang, Jialei Zhu, Yanbing Fan, Wei Hu, Libin Wu, Xiaodong Li, Lujie Ren, Chandra Mouli Pavuluri, Xiaole Pan, Yele Sun, Zifa Wang, Kimitaka Kawamura, and Pingqing Fu
Atmos. Chem. Phys., 22, 6449–6470, https://doi.org/10.5194/acp-22-6449-2022, https://doi.org/10.5194/acp-22-6449-2022, 2022
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Light-absorbing brown carbon (BrC) plays an important role in climate change and atmospheric chemistry. Here we investigated the seasonal and diurnal variations in water-soluble BrC in PM2.5 in the megacity Tianjin in coastal China. Results of the source apportionments from the combination with organic molecular compositions and optical properties of water-soluble BrC reveal a large contribution from primary bioaerosol particles to BrC in the urban atmosphere.
Zixuan Jia, Ruth M. Doherty, Carlos Ordóñez, Chaofan Li, Oliver Wild, Shipra Jain, and Xiao Tang
Atmos. Chem. Phys., 22, 6471–6487, https://doi.org/10.5194/acp-22-6471-2022, https://doi.org/10.5194/acp-22-6471-2022, 2022
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This study investigates the modulation of daily PM2.5 over three major populated regions in China by regional meteorology and large-scale circulation during winter. These results demonstrate the benefits of considering the large-scale circulation for air quality studies. The novel circulation indices proposed here can explain a considerable fraction of the day-to-day variability of PM2.5 and can be combined with regional meteorology to improve our capability to predict the variability of PM2.5.
Haibo Wang, Ting Yang, Zifa Wang, Jianjun Li, Wenxuan Chai, Guigang Tang, Lei Kong, and Xueshun Chen
Geosci. Model Dev., 15, 3555–3585, https://doi.org/10.5194/gmd-15-3555-2022, https://doi.org/10.5194/gmd-15-3555-2022, 2022
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In this paper, we develop an online data coupled assimilation system (NAQPMS-PDAF) with the Eulerian atmospheric chemistry-transport model. NAQPMS-PDAF allows efficient use of large computational resources. The application and performance of the system are investigated by assimilating 1 month of vertical aerosol observations. The results show that NAQPMS-PDAF can significantly improve the performance of aerosol vertical structure simulation and reduce the uncertainty to a large extent.
Jiaxing Sun, Zhe Wang, Wei Zhou, Conghui Xie, Cheng Wu, Chun Chen, Tingting Han, Qingqing Wang, Zhijie Li, Jie Li, Pingqing Fu, Zifa Wang, and Yele Sun
Atmos. Chem. Phys., 22, 561–575, https://doi.org/10.5194/acp-22-561-2022, https://doi.org/10.5194/acp-22-561-2022, 2022
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We analyzed 9-year measurements of BC and aerosol optical properties from 2012 to 2020 in Beijing, China. Our results showed large reductions in BC and light extinction coefficient due to the Clean Air Action Plan. As a response, both SSA and mass extinction efficiency (MEE) showed considerable increases, demonstrating a future challenge in visibility improvement. The primary and secondary BrC was also separated and quantified, and the changes in radiative forcing of BC and BrC were estimated.
Qian Ye, Jie Li, Xueshun Chen, Huansheng Chen, Wenyi Yang, Huiyun Du, Xiaole Pan, Xiao Tang, Wei Wang, Lili Zhu, Jianjun Li, Zhe Wang, and Zifa Wang
Geosci. Model Dev., 14, 7573–7604, https://doi.org/10.5194/gmd-14-7573-2021, https://doi.org/10.5194/gmd-14-7573-2021, 2021
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We developed a global tropospheric atmospheric chemistry source–receptor model. This model can quantify the contributions of multiple air pollutants from various source regions in one simulation without introducing the nonlinear error of atmospheric chemistry. The S-R relationships of PM2.5 and O3 from a global high-resolution (0.5° × 0.5°) simulation were given and compared with previous studies. This model will be useful for creating a link between the scientific community and policymakers.
Yuting Zhang, Hang Liu, Shandong Lei, Wanyun Xu, Yu Tian, Weijie Yao, Xiaoyong Liu, Qi Liao, Jie Li, Chun Chen, Yele Sun, Pingqing Fu, Jinyuan Xin, Junji Cao, Xiaole Pan, and Zifa Wang
Atmos. Chem. Phys., 21, 17631–17648, https://doi.org/10.5194/acp-21-17631-2021, https://doi.org/10.5194/acp-21-17631-2021, 2021
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In this study, the authors used a single-particle soot photometer (SP2) to characterize the particle size, mixing state, and optical properties of black carbon aerosols in rural areas of the North China Plain in winter. Relatively warm and high-RH environments (RH > 50 %, −4° < T < 4 °) were more favorable to rBC aging than dry and cold environments (RH < 60 %, T < −8°). The paper emphasizes the importance of meteorological parameters in the mixing state of black carbon.
Junhua Wang, Baozhu Ge, Xueshun Chen, Jie Li, Keding Lu, Yayuan Dong, Lei Kong, Zifa Wang, and Yuanhang Zhang
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2021-259, https://doi.org/10.5194/gmd-2021-259, 2021
Revised manuscript not accepted
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This paper developed a novel quantitative decoupling analysis (QDA) method to quantify the contributions of emission, meteorology, chemical reaction, and their nonlinear interactions on PM2.5 and applied it to a pollution episode in Beijing. This method can provides the researchers and policy makers with valuable information for understanding of key factors to heavy pollution, but also help the modelers to find out the sources of uncertainties among numerical models.
Hong Ren, Wei Hu, Lianfang Wei, Siyao Yue, Jian Zhao, Linjie Li, Libin Wu, Wanyu Zhao, Lujie Ren, Mingjie Kang, Qiaorong Xie, Sihui Su, Xiaole Pan, Zifa Wang, Yele Sun, Kimitaka Kawamura, and Pingqing Fu
Atmos. Chem. Phys., 21, 12949–12963, https://doi.org/10.5194/acp-21-12949-2021, https://doi.org/10.5194/acp-21-12949-2021, 2021
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This study presents vertical profiles of biogenic and anthropogenic secondary organic aerosols (SOAs) in the urban boundary layer based on a 325 m tower in Beijing in late summer. The increases in the isoprene and toluene SOAs with height were found to be more related to regional transport, whereas the decrease in those from monoterpenes and sesquiterpene were more subject to local emissions. Such complicated vertical distributions of SOA should be considered in future modeling work.
Qiaorong Xie, Sihui Su, Jing Chen, Yuqing Dai, Siyao Yue, Hang Su, Haijie Tong, Wanyu Zhao, Lujie Ren, Yisheng Xu, Dong Cao, Ying Li, Yele Sun, Zifa Wang, Cong-Qiang Liu, Kimitaka Kawamura, Guibin Jiang, Yafang Cheng, and Pingqing Fu
Atmos. Chem. Phys., 21, 11453–11465, https://doi.org/10.5194/acp-21-11453-2021, https://doi.org/10.5194/acp-21-11453-2021, 2021
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This study investigated the role of nighttime chemistry during Chinese New Year's Eve that enhances the formation of nitrooxy organosulfates in the aerosol phase. Results show that anthropogenic precursors, together with biogenic ones, considerably contribute to the formation of low-volatility nitrooxy OSs. Our study provides detailed molecular composition of firework-related aerosols, which gives new insights into the physicochemical properties and potential health effects of urban aerosols.
Ying Wei, Xueshun Chen, Huansheng Chen, Yele Sun, Wenyi Yang, Huiyun Du, Qizhong Wu, Dan Chen, Xiujuan Zhao, Jie Li, and Zifa Wang
Geosci. Model Dev., 14, 4411–4428, https://doi.org/10.5194/gmd-14-4411-2021, https://doi.org/10.5194/gmd-14-4411-2021, 2021
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The sub-grid particle formation (SGPF) in plumes plays an important role in air pollution and climate. We coupled an SGPF scheme to a chemical transport model with an aerosol microphysics module and applied it to investigate the SGPF impact over China. The scheme clearly improved the model performance in simulating aerosol components and particle number at typical sites influenced by point sources. The results indicate the significant effects of SGPF on aerosol particles in industrial areas.
Baozhu Ge, Danhui Xu, Oliver Wild, Xuefeng Yao, Junhua Wang, Xueshun Chen, Qixin Tan, Xiaole Pan, and Zifa Wang
Atmos. Chem. Phys., 21, 9441–9454, https://doi.org/10.5194/acp-21-9441-2021, https://doi.org/10.5194/acp-21-9441-2021, 2021
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In this study, an improved sequential sampling method is developed and implemented to estimate the contribution of below-cloud and in-cloud wet deposition over four years of measurements in Beijing. We find that the contribution of below-cloud scavenging for Ca2+, SO4 2–, and NH4+ decreases from above 50 % in 2014 to below 40 % in 2017. This suggests that the Action Plan has mitigated particulate matter pollution in the surface layer and hence decreased scavenging due to the washout process.
Xueshun Chen, Fangqun Yu, Wenyi Yang, Yele Sun, Huansheng Chen, Wei Du, Jian Zhao, Ying Wei, Lianfang Wei, Huiyun Du, Zhe Wang, Qizhong Wu, Jie Li, Junling An, and Zifa Wang
Atmos. Chem. Phys., 21, 9343–9366, https://doi.org/10.5194/acp-21-9343-2021, https://doi.org/10.5194/acp-21-9343-2021, 2021
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Atmospheric aerosol particles have significant climate and health effects that depend on aerosol size, composition, and mixing state. A new global-regional nested aerosol model with an advanced particle microphysics module and a volatility basis set organic aerosol module was developed to simulate aerosol microphysical processes. Simulations strongly suggest the important role of anthropogenic organic species in particle formation over the areas influenced by anthropogenic sources.
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Short summary
We develop a novel data assimilation system by integrating incremental machine learning with a localized ensemble Kalman filter to enhance the simulation and reanalysis of particulate matter < 2.5 µm chemical components. Compared to traditional chemical transport model-based data assimilation, our assimilation system has superior computational efficiency and simulation improvements. Comparisons with independent observations and reanalysis datasets validate the robust performance of our system.
We develop a novel data assimilation system by integrating incremental machine learning with a...
