Broadband Cavity-enhanced Absorption Spectroscopy Measurement of Atmospheric Trace Gases and Rayleigh Scattering Cross Sections in the Visible and Ultraviolet
Notice bibliographique
Résumé
This thesis reports on two incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instruments constructed in the cyan (470-540 nm) and the near-UV (350-400 nm) regions of the electromagnetic spectrum. Both devices realized enhancements in their absorption path of several kilometres from a 1 metre-long cavity while being of a compact design, light weight and of small power consumption. The cyan IBBCEAS was used to quantify NO2 and I2 in laboratory air. The instrument operated along a continuous wave cavity ring-down spectroscopy (cw-CRDS) device during a month-long field deployment on Vancouver Island, BC. The cyan IBBCEAS correlated well with the CRDS NO2 measurements (r2 = 0.70). Mixing ratios of I2 were below the limit of detection. The Rayleigh scattering cross-sections of air, N2, O2, Ar, CH4, and CO2 were measured and agreed with literature within measurement uncertainty. The absorption cross-sections of the weakly-bound O2-O2 and the CH4-CH4 collision complexes were also derived. The near-UV IBBCEAS instrument (nicknamed HODOR) measured NO2, HONO and O4 in the laboratory. NO2 and HONO measurements were compared against a TD-CRDS instrument. The results were highly correlated with respect to both species, r2 = 0.973 for NO2 and r2 = 0.978 for HONO, while O4 was measured in cylinder air only. HODOR's LOD (79 pptv in 60 s) with respect to HONO was comparable to state-of-the-art IBBCEAS instruments. HODOR was deployed during two short measurement intensives at the University of Calgary in Apr and Aug 2018 and quantified HONO for the first time in the urban atmospheric boundary layer of Calgary. HONO varied between 10 pptv and 1.43 ppbv during the intensives. Photolysis of HONO was a larger source of hydroxyl radicals than the reaction of O1D with H2O. Rayleigh scattering cross-sections of several gases were measured in the near-UV and agreed with literature. The absorption cross-section of O2-O2 between 350 and 400 nm was also reported. The near-UV IBBCEAS instrument was applied to the characterization of HONO interference in a photolytic NO2 converter. Overall, this work delivered two IBBCEAS instruments which were well-characterized, validated and tested in the laboratory and during field deployments.
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 ».