https://orfeo.belnet.be:443 The ORFEO digital repository system captures, stores, indexes, preserves, and distributes digital research material. 2026-06-08T20:23:48Z https://orfeo.belnet.be/handle/internal/14773 Geostationary observations of atmospheric ammonia over East Asia: spatio-temporal variations revealed by three years of FY-4B/GIIRS measurements Sheng, M.; Zhou, R.; Hua, J.; Han, S.; Liu, S.; Zhang, L.; Wang, W.; Dang, R.; Cao, H.; Chen, Z.; Gu, Y.; Liu, M.; Lee, L.; Qi, C.; Lu, F.; Han, C.; Shephard, M.W.; Guendouz, N.; Viatte, C.; Clarisse, L.; Van Damme, M.; Clerbaux, C.; Zeng, Z.-C. Satellite observations play a crucial role in quantifying ammonia sources by capturing large-scale variations of atmospheric NH3 concentrations. As the world's first geostationary hyperspectral infrared sounder, the Geostationary Interferometric Infrared Sounder (GIIRS) on board China's FengYun-4 satellite series provides a unique opportunity to monitor the diurnal cycle of NH3. Using NH3 retrievals from July 2022 to June 2025, this study investigates the spatio-temporal variability of NH3 columns over East Asia, with a focus on daytime variations (07:00–19:00 LT – local time) in major agricultural regions. Inter-comparison with polar-orbiting IASI and CrIS data shows that GIIRS NH3 retrievals are consistent in capturing spatial patterns and temporal dynamics. The NH3 peaks occur between March and July, with peak timing earlier in the south and later in the north, reflecting regional differences primarily driven by agricultural activities. Validation with ground-based FTIR measurements at Hefei in eastern China demonstrates the accuracy of GIIRS NH3, with a correlation coefficient of 0.77 and an RMSE of 9.67×1015 molec cm−2, while reproducing daytime variations observed by FTIR. For major agricultural areas, the NH3 columns generally increase from early morning to late afternoon, reaching 1.10–1.56 times morning levels in summer and spring. Compared with GEOS-CF model simulations, the results reveal pronounced discrepancies in spatial distributions over the Sichuan Basin in southwestern China and daytime variations over northern India. These findings highlight the valuable capability of FY-4B/GIIRS in identifying and tracking daytime dynamics of NH3 sources over East Asia, offering new insights beyond current low-Earth orbit (LEO) instruments. https://orfeo.belnet.be/handle/internal/14772 Introduction to multidisciplinary special collection: Solar Wind: Origin, acceleration, and Outflow Pierrard, V. On the occasion of the 50 years since the launch of Helios 1 and Helios 2, we proposed a special collection related to the solar wind, its origin, evolution, and space weather related effects. In addition to old missions like ULYSSES that explored the solar wind outside the ecliptic plane, recent missions like the Parker Solar Probe (PSP) and Solar Orbiter (SolO), as well as established ones such as the Solar Dynamics Observatory (SDO) and the Solar Terrestrial Relations Observatories (STEREOs), offer extensive new measurements that help to refine existing knowledge of slow and fast solar wind in the heliosphere and the development of new models. This collection addressed different solar wind topics, which included but were not limited to the mechanisms of solar wind acceleration and outflow, dynamics of stream interaction, the configuration of the magnetic field and plasma topology at the source surface and within the inner heliosphere. https://orfeo.belnet.be/handle/internal/14770 Témoins de la libération, trois femmes, trois pays, trois destins : Des journaux intimes entre résilience et espoir de Sélys, Elodie; Maquet, Hélène; Kesteloot, Chantal Delpâture, Gorian À la fin de la Seconde Guerre mondiale, trois femmes, à Milan, Paris et Berlin, racontent dans leurs journaux intimes les jours tumultueux de la libération. À travers leurs émotions, leurs doutes et leur courage, elles offrent un regard profondément humain sur un moment historique majeur. Leurs récits, éclairés par des spécialistes, révèlent le rôle essentiel des femmes pendant la guerre et la force que représente l'écriture pour survivre. Ces journaux sont un témoignage puissant de résilience et d'espoir.; Elodie de Sélys et Hélène Maquet vous proposent un documentaire historique suivi d’un débat avec Chantal Kesteloot et Bénédicte Rochet.; ▶️ À regarder sur auvio RTBF 2026-01-01T00:00:00Z https://orfeo.belnet.be/handle/internal/14769 The Moral and Historical Imperative of Two Centuries of Prison Archives; L'impératif moral et historique de deux siècles d'archives pénitentiaires Deceulaer, Harald; Spronck, Vincent; Rousseaux, Xavier PanoptiK propose une traversée inédite de la condition carcérale à Bruxelles, en déployant plus de dix années de travail mené au cœur des prisons de Forest, Saint-Gilles et Berkendael. Ce livre mêle les images contemporaines de Cédric Gerbehaye, des documents d’archives exceptionnels et les textes de deux historiens pour interroger la prison comme lieu à la fois concret, quotidien, et profondément symbolique.; Une plongée sans précédent au cœur des prisons bruxelloises, où un siècle d’images révèle la réalité, la mémoire et les métamorphoses de l’enfermement.; Photographies : Cédric Gerbehaye; Texte: Xavier Rousseaux, Harald Deceulaer, Vincent Spronck 2026-01-01T00:00:00Z