Chia-Hua Hsu, Daven K. Henze, Arthur P. Mizzi, Colin Harkins, Congmeng Lyu, Owen R. Cooper, Rebecca H. Schwantes, Jian He, Meng Li, Siyuan Wang, Chelsea E. Stockwell, Carsten Warneke, Andrew W. Rollins, Eleanor M. Waxman, Kristen Zuraski, Jeff Peischl, Shobha Kondragunta, Fangjun Li, Chuanyu Xu, R. Bradley Pierce, Gonzalo González Abad, Caroline R. Nowlan, Xiong Liu, Brian C. McDonald
The operation of geostationary (GEO) instruments such as the Tropospheric Emissions: Monitoring of Pollution (TEMPO) provides unprecedented hourly nitrogen dioxide (NO2) observations compared to the once-daily data from a low-Earth orbit (LEO) platform like the TROPOspheric Monitoring Instrument (TROPOMI). This study investigates the performance and challenges of using TEMPO versus TROPOMI measurements to constrain anthropogenic nitrogen oxides (NOx) emissions. The accuracy of TEMPO and TROPOMI NO2 tropospheric columns are assessed using Pandora observations, finding a low bias of 9%–12.3% in TEMPO, and TROPOMI data during August 2023, while TEMPO midday and late afternoon observations are less of low bias. Top-down NOx emissions derived by midday TEMPO and TROPOMI data are generally consistent over urban areas, being 5%–20% lower than bottom-up emissions provided by the 2021 GReenhouse gas And Air Pollutants Emissions System (GRA2PES), and align with 2023 GRA2PES emissions, demonstrating the reliability of using satellite data for timely updates of bottom-up inventories. However, assimilating additional morning/late afternoon TEMPO data leads to the poorest top-down NOx emissions, likely resulting from larger negative measurement biases. NOx emission inversions effectively mitigate NOx overprediction, though the top-down NOx emissions might be over-corrected in urban cores. NOx emissions optimization also improves ozone forecasts by reducing the model's positive biases, especially when assimilating midday TEMPO data. Our study suggests that TEMPO midday observations provide better constraints on the magnitude and spatiotemporal variation of anthropogenic NOx emissions than TROPOMI, while morning TEMPO v3 data should be used cautiously due to potential negative impact on NOx emissions inversion.
{"title":"Top-Down Estimates of U.S. NOx Emissions Using TEMPO and TROPOMI NO2 Remote Sensing Observations With WRF-Chem/Chem-DART","authors":"Chia-Hua Hsu, Daven K. Henze, Arthur P. Mizzi, Colin Harkins, Congmeng Lyu, Owen R. Cooper, Rebecca H. Schwantes, Jian He, Meng Li, Siyuan Wang, Chelsea E. Stockwell, Carsten Warneke, Andrew W. Rollins, Eleanor M. Waxman, Kristen Zuraski, Jeff Peischl, Shobha Kondragunta, Fangjun Li, Chuanyu Xu, R. Bradley Pierce, Gonzalo González Abad, Caroline R. Nowlan, Xiong Liu, Brian C. McDonald","doi":"10.1029/2025JD044223","DOIUrl":"https://doi.org/10.1029/2025JD044223","url":null,"abstract":"<p>The operation of geostationary (GEO) instruments such as the Tropospheric Emissions: Monitoring of Pollution (TEMPO) provides unprecedented hourly nitrogen dioxide (NO<sub>2</sub>) observations compared to the once-daily data from a low-Earth orbit (LEO) platform like the TROPOspheric Monitoring Instrument (TROPOMI). This study investigates the performance and challenges of using TEMPO versus TROPOMI measurements to constrain anthropogenic nitrogen oxides (NO<sub>x</sub>) emissions. The accuracy of TEMPO and TROPOMI NO<sub>2</sub> tropospheric columns are assessed using Pandora observations, finding a low bias of 9%–12.3% in TEMPO, and TROPOMI data during August 2023, while TEMPO midday and late afternoon observations are less of low bias. Top-down NO<sub><i>x</i></sub> emissions derived by midday TEMPO and TROPOMI data are generally consistent over urban areas, being 5%–20% lower than bottom-up emissions provided by the 2021 GReenhouse gas And Air Pollutants Emissions System (GRA<sup>2</sup>PES), and align with 2023 GRA<sup>2</sup>PES emissions, demonstrating the reliability of using satellite data for timely updates of bottom-up inventories. However, assimilating additional morning/late afternoon TEMPO data leads to the poorest top-down NO<sub><i>x</i></sub> emissions, likely resulting from larger negative measurement biases. NO<sub><i>x</i></sub> emission inversions effectively mitigate NO<sub><i>x</i></sub> overprediction, though the top-down NO<sub><i>x</i></sub> emissions might be over-corrected in urban cores. NO<sub><i>x</i></sub> emissions optimization also improves ozone forecasts by reducing the model's positive biases, especially when assimilating midday TEMPO data. Our study suggests that TEMPO midday observations provide better constraints on the magnitude and spatiotemporal variation of anthropogenic NO<sub><i>x</i></sub> emissions than TROPOMI, while morning TEMPO v3 data should be used cautiously due to potential negative impact on NO<sub><i>x</i></sub> emissions inversion.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 2","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146091102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Line-shaped contrails formed behind aircraft can evolve into broadly spread and long-living cirrus clouds under favorable conditions. These contrail-cirrus contribute significantly to the aviation-induced radiative forcing. While past modeling studies have examined contrail-cirrus across various atmospheric and aircraft-type dependent parameters, they have focused on conventional kerosene combustion. In this study, we investigate how the switch to an alternative propulsion system, such as hydrogen combustion, may alter contrail-cirrus properties using the large-eddy simulation (LES) model EULAG coupled with the Lagrangian Cloud Module (LCM), a particle-based microphysics module. Building on prior work that modeled hydrogen contrails during the vortex phase, we use those results to initialize the subsequent contrail-cirrus evolution. We explore a wide range of background meteorological conditions, including variations of ambient temperature, relative humidity with respect to ice, vertical wind shear, and updraft velocity, and assess two aircraft types. Key contrail properties, such as total ice crystal number and mass, are found to be most sensitive to the initial number of ice crystals and ambient temperature. We show that reducing the number of initially formed ice crystals substantially decreases contrail radiative impact. This is primarily due to a shorter contrail-cirrus lifetime, driven by the earlier onset and more efficient sedimentation of the fewer but larger ice crystals. Moreover, the relationship between radiative impact and initial ice crystal number is nonlinear, consistent with previous studies.
{"title":"Modeling the Impact of Alternative Fuels and Hydrogen Propulsion on Contrail-Cirrus: A Parameter Study","authors":"Annemarie Lottermoser, Simon Unterstrasser","doi":"10.1029/2025JD044604","DOIUrl":"https://doi.org/10.1029/2025JD044604","url":null,"abstract":"<p>Line-shaped contrails formed behind aircraft can evolve into broadly spread and long-living cirrus clouds under favorable conditions. These contrail-cirrus contribute significantly to the aviation-induced radiative forcing. While past modeling studies have examined contrail-cirrus across various atmospheric and aircraft-type dependent parameters, they have focused on conventional kerosene combustion. In this study, we investigate how the switch to an alternative propulsion system, such as hydrogen combustion, may alter contrail-cirrus properties using the large-eddy simulation (LES) model EULAG coupled with the Lagrangian Cloud Module (LCM), a particle-based microphysics module. Building on prior work that modeled hydrogen contrails during the vortex phase, we use those results to initialize the subsequent contrail-cirrus evolution. We explore a wide range of background meteorological conditions, including variations of ambient temperature, relative humidity with respect to ice, vertical wind shear, and updraft velocity, and assess two aircraft types. Key contrail properties, such as total ice crystal number and mass, are found to be most sensitive to the initial number of ice crystals and ambient temperature. We show that reducing the number of initially formed ice crystals substantially decreases contrail radiative impact. This is primarily due to a shorter contrail-cirrus lifetime, driven by the earlier onset and more efficient sedimentation of the fewer but larger ice crystals. Moreover, the relationship between radiative impact and initial ice crystal number is nonlinear, consistent with previous studies.</p>","PeriodicalId":15986,"journal":{"name":"Journal of Geophysical Research: Atmospheres","volume":"131 2","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JD044604","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146091105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yazmina Rojas-Beltran, Jason M. Cordeira, F. Martin Ralph, Chad W. Hecht
This study uses wind profiler data to examine the characteristics of the Sierra Barrier Jet (SBJ) over 23 cool seasons (October 2000–March 2023) and its influence on precipitation in Northern California. The analysis identifies 439 SBJ events, with a mean maximum wind speed of 25.6