Quantile function based, optical characterisation of the Nelson River plume dispersion in Hudson Bay (Canada)
Notice bibliographique
Résumé
This study hypothesizes, that sediment-based optical estimation of plume extent underestimates the dispersion limit of river discharge in marine waters. Optically active Colour Dissolved Organic Matter (CDOM) has been used as a tracer along with suspended sediments to validate the hypothesis, for the Nelson River (NR) plume in southwest Hudson Bay (HB). Remote sensing reflectance (Rrs) band ratio (Rrs 678nm/488nm) was tuned in to retrieve CDOM absorbance at 412nm: aCDOM (412nm) from Moderate Resolution Imaging Spectroradiometer (MODIS) images. Similarly, Rrs (678nm) was used for TSS concentration retrieval. Plume dispersion characteristics were compared for spring and neap tidal periods during a high (2005) and a normal (2006) discharge year. Quantile function (QF) provides variable values (aCDOM, TSS concentration) for a given cumulative probability. It was assumed that 0.90 QF (10% of the data distribution) is a representative of the river plume function, while 0.05 QF (95% of the data distribution) represents the ocean end-member values. These threshold values were calculated for each of the cumulative areas of coastal waters of southwest HB with NR mouth as the origin, limited till 500 km radial distance. Thresholds averaged over 0 km to 50km was used as the reference for estimation of river plume dilution. A conditional approach of the plume extent limit was set to the point at which the QF dilution (0.90-0.50) equals to the QF dilution (0.90-0.05). This dilution conditionality was satisfied for CDOM but was never achieved for TSS, indicating the additional source of sediment influx. Plume discharge volume was proportional to the aCDOM (412nm) plume extent threshold for all tidal periods. This threshold value was observed at ~250km during neap ebb tide (NET) for both years. While a shorter extent (150 km) was observed during the 2005 spring ebb tide (SET) and ~300km for the same tidal period during 2006. The point of minimum variance within aCDOM (412nm) dilution (0.50 to 0.90 QF) was used as a representative of the freshwater-marine boundary. An extent of 400km (SET) and 350km (NET) for 2005 was recorded, with a 500km extent observed for both ebb tides in 2006. A lower aCDOM (412nm) dispersion threshold was observed for the SET (0.39 m-1) than the NET (0.59 m-1) for 2005 and vice-versa for 2006. A weak, negative correlation of aCDOM (412nm) minimum variance threshold between 2005 and 2006 indicated a weaker influence of discharge beyond the maximum variance threshold. This dispersion is expected to be controlled by a cyclonic eddy in southwest HB. Modeled dilution slope of aCDOM (412nm), <200km showed a significant influence of discharge with higher slope values obtained for 2005 for both spring and neap ebb tide conditions. The minimum variance of TSS concentration dilution is limited within 200-250 km, while its maximum variance is limited within 100km. Thus, TSS underestimates the river plume dispersion extent, which is better represented by CDOM of terrestrial provenance.
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 machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| 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) | 0,001 | 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 source (Gemma direct ou Codex distillé), 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 ».