Variability of north Pacific ocean surface sensible and latent heat fluxes
Notice bibliographique
Résumé
Interannual variability in North Pacific Ocean (20°N — 56°N) winter-time surface sen sible and latent heat fluxes and their relation to Northern Hemisphere sea-level pressure and 500 mb height fields is explored. Observational data based on the Comprehen sive Ocean-Atmosphere Data Set (COADS) and National Meteorological Center (NMC) gridded data set over the 1950—89 period are analysed and compared with 10 years of simulated data from the Canadian Climate Centre (CCC) second generation general cir culation model (GCM). Two regions of the North Pacific Ocean are examined closely: the Kuroshio Current region (KCR), where the mean and anomalies of the heat fluxes are largest (implying a strong link between the ocean and atmosphere); and a region in the central North Pacific (NPR) near 3l°N 165°W where the heat flux means and anomalies are moderately large and where several authors have found a strong correlation between sea surface temperatures and the Northern Hemisphere atmospheric circulation. In the COADS/NMC data, positive KCR heat flux anomalies are associated with sig nificant differences from the climatological mean atmospheric fields: there are stronger ridges over Eastern Asia and Western North America, and deeper troughs over the North west Pacific and Northwest Atlantic. These patterns are similar to previous modelling studies of the atmospheric response to positive heat flux and sea surface temperature anomalies, and to a dominant mode of variability observed in the 500 mb height field known as the Western Pacific (WP) pattern. The corresponding GCM relations are quite different. Positive KCR heat flux anomalies are associated with a deeper trough over the Northeast Pacific and Northwest Atlantic at sea-level pressure, and a deeper trough over the Northwest Pacific at 500 mb. The atmospheric anomalies associated with NPR heat flux anomalies are generally weaker than those accompanying KCR heat flux anomalies. In the COADS/NMC data, positive NPR latent heat flux anomalies are associated with deeper troughs over the Northeast Pacific and Eastern North America, stronger jets, a stronger ridge over Western North America, and a more intense Aleutian Low. However, positive NPR sensible heat flux anomalies are associated with weaker atmospheric anomalies in the opposite sense: a shallower trough over Eastern North America, a weaker North American Jet, a weaker ridge over Western North America, and a less intense Aleutian Low. The corresponding GCM relations are somewhat similar, with positive NPR heat flux anomalies accompanied by a deeper trough over the Northeast Pacific and a stronger ridge and weaker trough over North America. VARIMAX rotated principal component analysis shows the two dominant modes of variation of COADS and GCM sensible and latent heat fluxes are strongly associated with variability over KCR and NPR, respectively. The greater complexity of the GCM principal components may reflect the smaller signal-to-noise ratio in the model data and the limitations of the mixed-layer ocean model. It also suggests spatial autocorrelation within the COADS and GCM heat flux fields is very different. This difference may have important implications for a more complete assessment of the model’s simulation of both the observed atmospheric fields (“current” climate) and the anticipated changes in atmospheric circulation due to anthropogenic emissions of greenhouse gases.
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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 | 0,000 | 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 ».