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Subtropical southern Africa fire emissions of nitrogen oxides and ammonia obtained with satellite observations and GEOS-Chem
No full textLandscape fires in subtropical southern Africa (2–20°S) are a prominent regional source of nitrogen oxides (NOx) and ammonia (NH3), affecting climate and air quality as precursors of tropospheric ozone and aerosols. Here we evaluate GEOS-Chem model skill at reproducing satellite observations of vertical column densities of NO2 from TROPOMI and NH3 from IASI driven with three distinct and widely used biomass burning inventories (FINNv2.5, GFEDv4s, GFASv1.2). We identify that GFASv1.2 use of fire radiative power and a NOx emission factor that is almost half that used by the other two inventories is most consistent with TROPOMI and that FINNv2.5 use of active fires and landscape-specific fuel loads and biomass consumed is most consistent with IASI. We use a simple mass-balance inversion to calculate top-down NOx emissions of 1.9 ± 0.6 Tg NO for June–October and NH3 emissions of 1.2 ± 0.4 Tg for July–October. All inventories collocate NOx and NH3 emissions, whereas most of the pronounced emissions of NOx and NH3 are separate and have distinct seasonality in the top-down estimate. We infer with GEOS-Chem more efficient ozone production (13 Tg ozone per Tg NO) with the top-down informed NOx emissions than the inventory emissions, as GFASv1.2 NOx is almost 20% less than top-down NOx and the 2.3- to 2.5-times greater FINNv2.5 and GFEDv4s NOx reduces sensitivity of ozone formation to NOx. Both NOx and NH3 top-down emissions are unaffected by use of plume injection heights, limited to GFASv1.2 in GEOS-Chem, and NH3 is insensitive to acidic sulfate and nitrate aerosol emissions absent in all inventories. The top-down emissions estimates and comparison to satellite observations suggest a hybrid bottom-up approach could be adopted to discern byproducts of smouldering and flaming fires
Thermodynamics of Observations
Get PDFThis work demonstrates that the four laws of classical thermodynamics apply to the statistics of symmetric observation distributions, and provides examples of how this can be exploited in uncertainty assessments. First, an expression for the partition function Z is derived. In contrast with general classical thermodynamics, however, this can be performed without the need for variational calculus, while Z also equals the number of observations N directly. Apart from the partition function ≡ as a scaling factor, three state variables m, n, and fully statistically characterize the observation distribution, corresponding to its expectation value, degrees of freedom, and random error, respectively. Each term in the first law of thermodynamics is then shown to be a variation on 2=()2 for both canonical (constant n and ) and macro-canonical (constant ) observation ensembles, while micro-canonical ensembles correspond to a single observation result bin having 2=0. This view enables the improved fitting and combining of observation distributions, capturing both measurand variability and measurement precision
Design, manufacturing, and assembly of the GRASS small body gravimeter spring
No full textThe GRAvimeter for small Solar System bodies (GRASS) is a novel spring-based gravimeter for the application in extremely low-gravity environments on small bodies in our Solar System. It is one of the Juventas CubeSat payloads as part of the ESA Hera mission to measure the surface gravity on the asteroid moon Dimorphos. The GRASS gravimeter was successfully launched on-board Hera on 7 October 2024. Key element of this instrument is the gravimeter spring, a cantilever-type bending spring, allowing for measurements at arbitrary instrument orientation. This paper presents the design, manufacturing, and integration of the developed sensing element assembly. The spring design can serve as a future reference for data analysis of the gravimeter data obtained in-situ on extraterrestrial surfaces. The manufacturing process is detailed, including the raw material, laser cutting, heat treatment, and gold sputtering. The step-by-step assembly describes the integration of the spring assembly which includes the clamping of the spring and the tip mass, added to the spring to realise larger deflections and henceforth increase the sensitivity of the instrument for the small body gravity environment
Inventaire des archives de la commune d’Antheit : Dépôt 2024 (1793 (1800) - 1977 (1978))
Get PDFLes archives communales d’Antheit (1800-1977) retracent deux siècles de vie locale, marqués par l’essor industriel, les mutations administratives et la fusion avec Wanze. Classé et décrit dans le cadre du projet « Archives locales de Wallonie », ce fonds offre une source essentielle sur l’histoire politique, sociale et économique du village.The records described in this inventory are held at the State Archives in Liège (inventory code 523 - P73).This inventory is the fixed published version dated 2-12-2025. For the dynamic inventory under active revision, including recent updates and additions, please consult our online search platform AGATHA. In AGATHA, you can also request the archival items you wish to consult in the reading room
Ozone Pollution Extremes in Southeast China Exacerbated by Reduced Uptake by Vegetation During Hot Droughts
No full textUsing a decade of observations and chemistry-climate model simulations (2014–2023), we highlight the key role of biosphere-atmosphere interactions in driving late summer–autumn ozone pollution extremes over Southeast China during hot droughts. In the 2019 and 2022 droughts, stomatal closure in the Yangtze River Basin, caused by soil moisture deficits, led to ∼60% reductions in ozone deposition rates to vegetation, aligning with reduced photosynthesis inferred from satellite remote sensing of solar induced fluorescence. Ozone production increased due to higher isoprene emissions from heat stress, NOx-rich airflow from North China, and enhanced solar radiation. Soil drought intensified temperatures and increased isoprene emissions by 27%, but these only had marginal impact on ozone (<5 ppbv) in South China, where ozone formation is NOx-limited. Reduced ozone uptake by drought-stressed vegetation played a dominant role, driving 10–20 ppbv increases in daily maximum 8-hr average ozone concentrations and a threefold rise in events exceeding 100 ppbv
Inventaire des archives du château de Maredsous à Denée (1872-1930)
No full textDécouvrez l’univers remarquable de la famille Desclée, industriels, éditeurs et mécènes à l’origine du rayonnement spirituel et artistique de Maredsous. Leur acquisition du domaine en 1872 mène à la fondation de l’abbaye bénédictine, puis de Maredret, tout en accompagnant l’essor d’entreprises novatrices à Tournai, Bruges et Roubaix. Les archives du château témoignent de la gestion des domaines ruraux, du développement des maisons d’édition Desclée et des nombreuses activités industrielles, agricoles et culturelles du clan. Couvrant 1872-1930, ce fonds exceptionnel éclaire l’histoire d’une famille au rôle majeur dans la région et bien au-delà.The records described in this inventory are held at the State Archives in Namur (inventory code 525 - I 261).This inventory is the fixed published version dated 31-12-2025. For the dynamic inventory under active revision, including recent updates and additions, please consult our online search platform AGATHA. In AGATHA, you can also request the archival items you wish to consult in the reading room
Rapport annuel Archives de l'État 2024
No full text2024 fut une année charnière pour les Archives de l’État : entre pression budgétaire et renouvellement numérique, l’institution a démontré sa résilience. Grâce à une discipline budgétaire stricte, des choix stratégiques et le lancement d’AGATHA, un environnement de recherche en ligne innovant, les Archives de l’État ont continué à bâtir une mémoire collective accessible et tournée vers l’avenir. Malgré des moyens limités, la mission est restée claire : conserver, partager et éclairer le savoir. Ce rapport annuel montre comment l’institution a renforcé son rôle de garante de la transparence et de la démocratie, et comment elle continue – au cœur de l’incertitude – d’investir dans un futur numérique où histoire et société se rencontrent
Considerations on the process of target selection for the Comet Interceptor mission
No full textComet Interceptor is an ESA science mission with payload contributions from ESA Member States and with an international participation by JAXA. It is the first mission that is being designed, built, and potentially launched before its target is known. This approach will enable the spacecraft to perform the first mission to a Long Period Comet from the Oort Cloud, as these comets have fleeting visits to the inner Solar System lasting only months to years from first discovery, too short for the usual process of mission development to be followed. In this paper we describe a number of factors that need to be considered in selecting a target for the mission, including scientific, orbital, spacecraft and instrument constraints, and discussion of different prioritisation strategies. We find that, in the case where we have a choice of targets, our decisions will mostly be driven by orbital information, which we will have relatively early on, with information on the activity level of the comet an important but secondary consideration. As cometary activity levels are notoriously hard to predict based on early observations alone, this prioritisation / decision approach based more on orbits gives us confidence that a good comet that is compatible with the spacecraft constraints will be selectable with sufficient warning time to allow the mission to intercept it