| Title: |
Monitoring Atmospheric Ammonia From Geostationary Orbit: Contributions of GIIRS‐B and IRS Remote Sensors. |
| Authors: |
Guendouz, Nadir1 (AUTHOR); Viatte, Camille1 (AUTHOR) camille.viatte@latmos.ipsl.fr; Zeng, Zhao‐Cheng2 (AUTHOR); Boynard, Anne1,3 (AUTHOR); Safieddine, Sarah1 (AUTHOR); Standfuss, Carsten3 (AUTHOR); Turquety, Solène1 (AUTHOR); Van Damme, Martin4,5 (AUTHOR); Clarisse, Lieven4 (AUTHOR); Coheur, Pierre4 (AUTHOR); Sheng, Mengya2 (AUTHOR); Armante, Raymond6 (AUTHOR); Prunet, Pascal3 (AUTHOR); Clerbaux, Cathy1,4 (AUTHOR) |
| Source: |
Journal of Geophysical Research. Atmospheres. May2026, Vol. 131 Issue 10, p1-18. 18p. |
| Subject Terms: |
*Atmospheric ammonia; *Air quality; Geostationary satellites; Remote sensing; IR spectrometers; Diurnal variations in meteorology |
| Geographic Terms: |
East Asia; Asia; China |
| Abstract: |
Ammonia (NH3) is a short‐lived atmospheric pollutant with significant environmental and health impacts. Monitoring NH3 remains challenging, as diurnal variability at local scales is still poorly documented. In this study, we analyze two years (July 2022–June 2024) of NH3 total columns from the Geostationary Interferometric Infrared Sounder onboard China's FengYun‐4B (GIIRS‐B) over East Asia. After applying quality and uncertainty filters, we find good agreement with Infrared Atmospheric Sounding Interferometer (IASI) morning observations (weighted Pearson R = 0.64) and identify relationships between NH3 and skin/land surface temperature over five major NH3 hotspots, suggesting contributions from agriculture (urea fertilizer use), livestock, and secondary urban sources. GIIRS‐B's high temporal resolution reveals a clear bimodal diurnal pattern, with NH3 enhancements in the early morning and mid‐afternoon in four regions. A dedicated analysis of GIIRS‐B NH3 retrieval uncertainties provides a realistic physical benchmark for geostationary infrared observations. Using radiative transfer simulations (4A/OP) driven by atmospheric chemistry model outputs (CHIMERE), we evaluate the potential of the European InfraRed Sounder (IRS) onboard MTG‐S to retrieve NH3 at sub‐daily resolution. IRS uncertainties are generally larger and more variable than those of IASI, but under favorable thermal‐contrast conditions they can become comparable. GIIRS‐B and IRS exhibit consistent diurnal uncertainty patterns with nighttime maxima and daytime minima, confirming the realism of the IRS performance assessment. These results highlight the added value of geostationary sounders for improving NH3 emission monitoring, source attribution, and diurnal process understanding in support of future European air‐quality regulations. Plain Language Summary: Ammonia (NH3) is an atmospheric pollutant that plays a key role in air quality and affects both the environment and human health. Measuring NH3 is difficult, especially for understanding its daily and spatial variability. This study explores how geostationary satellites can fill these gaps by offering frequent measurements over the same region. We analyzed 2 years of data from GIIRS‐B, a geostationary hyperspectral infrared sounder on China's FengYun‐4B satellite observing East Asia. We found good agreement with IASI, a well‐known polar‐orbiting instrument measuring NH3 total columns, and after applying quality and uncertainty filters, used GIIRS‐B data to explore how NH3 varies during the day and relates to skin temperature, indicating potential sources such as fertilizer use, livestock, traffic, or industry. Building on what GIIRS‐B demonstrates over East Asia, we used simulations to assess the capabilities of the recently launched European IRS instrument on the MTG‐S satellite to measure NH3, and compared these to IASI. Despite larger retrieval uncertainties, we show that under favorable conditions, IRS can sometimes reach uncertainties comparable to IASI. This study shows that geostationary satellites will greatly enhance our ability to monitor atmospheric ammonia daily variability to support new environmental regulations. Key Points: GIIRS‐B reveals NH3 source signatures and diurnal patterns over Asia from high‐frequency regional observationsIRS retrieval uncertainty approaches the accuracy of IASI under negative thermal contrast and afternoon overpassesIRS simulations show that it can resolve sub‐daily NH3 retrieval uncertainty variations, especially during thermal contrast peaks [ABSTRACT FROM AUTHOR] |
| : |
Copyright of Journal of Geophysical Research. Atmospheres is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| Database: |
GreenFILE |