Atmospheric Halocarbon Measurements with a focus on East and South-East Asia
Notice bibliographique
Résumé
A large variety of halocarbon species are present in the atmosphere and can significantly impact stratospheric ozone depletion and/or global warming. Compound use has been phased out, reduced and replaced for some species under global control measures such as the Montreal and Kyoto Protocols. However, relatively long atmospheric lifetimes, imperfect substitutes and incomplete reductions in usage mean that global abundances of halocarbon species still require regular monitoring. This is especially true for the rapidly developing East and South-East Asian regions where widespread emissions have been repeatedly reported in recent years. \nTo detect a variety of halocarbon mixing ratios, air samples are cryotrapped and analysed via gas chromatography couple with mass spectrometry (GC-MS). Highly sensitive and precise instrumentation widens this range further and the automation of the analysis system would improve and extend sample throughput. A semi-automated inlet system for a GC-MS set-up was constructed and cryotrapping with liquid nitrogen was tested successfully. \nIn the atmosphere, anthropogenic emissions are the main source of many halocarbons, however methyl halides also have large natural sources including from cultivated crops like rice. Using genetically mapped and altered Arabidopsis thaliana and Physcomitrella patens, methyl halide emission rates were calculated. Differences found when compared to wild type plants indicated the potential for developing ‘ozone-safe’ crops through manipulation of the HOL-gene, which may particularly benefit Asian emissions. \nThree short-term sampling campaigns based in Taiwan assessed abundances of mainly anthropogenically-sourced halocarbons in East Asia. Backwards trajectory modelling was used to estimate potential source regions and both enhanced and close to background mixing ratios were observed for a range of species. Pollution events and interspecies correlations were found for many halocarbons with poorly understood sources such as CFC-113a and HCFC-133a. \nA further short-term campaign based in Bachok, Malaysia assessed long-range transport of ozone-depleting species to South-East Asia during the cold surge phenomenon of the winter monsoon, when rapid vertical transport may occur. Short-lived species were observed at significantly high abundances suggesting their potential impact on stratospheric ozone may have been previously underestimated. \n
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».