Middle Atmosphere Response to ENSO Events in Northern Hemisphere Winter by the Whole Atmosphere Community Climate Model
Bibliographic record
Abstract
The influences of El Nio and La Nia sea surface temperature anomalies on the middle atmosphere are analyzed using a chemistry-climate model, the Whole Atmosphere Community Climate Model, version 3 (WACCM3), and the 40-year reanalysis dataset from the European Centre for Medium-range Weather Forecasts .Monthly mean data are used to perform statistical and dynamical analyses.Temperature anomalies are found in the stratosphere during both El Nio and La Nia years.These anomalies exhibit diverse distribution patterns, which we ascribe to the different scales of the planetary waves.During an El Nio winter, planetary waves are most active in December and January, leading to more disturbances of the stratospheric polar vortex and a higher frequency of stratospheric sudden warming (SSW) events.Moreover, on the basis of the three-dimensional Eliassen-Palm (E-P) flux, we find that the main wave action is located in the eastern hemisphere and displaces the polar vortex to the western hemisphere.These vortex displacements are closely connected to the weather and climate in the corresponding areas.In contrast, during a La Nia winter, planetary waves are most active in February and March, and most SSW events occur at the same time.The distribution of the E-P flux indicates that planetary wave fluctuations are located between 90E and 180E, resulting in a displacement of the polar vortex with some associated changes in the related atmospheric circulation.In addition, the mesospheric residual circulation (RC) reverses between February and March in both El Nio and La Nia years.Dynamical analyses using parameterized gravity waves show that the mesospheric meridional RC is closely connected to gravity-wave drag.This, in turn, is directly influenced by temperature and zonal wind patterns in the early and late winter of El Nio and La Nia years.These anomalies in the RC may influence the distribution of atmospheric constituents and should be explored further.RSUM [Traduit par la rdaction] Nous analysons l'influence des anomalies de temprature de surface de la mer de l'El Nio et de La Nia sur l'atmosphre moyenne au moyen d'un modle chimie-climat, le Whole Atmosphere Community Climate Model, version 3 (WACCM3), et de l'ensemble de donnes ranalyses de 40 ans du Centre europen pour les prvisions mtorologiques moyen terme (ERA-40).Nous utilisons les donnes mensuelles moyennes pour effectuer des analyses statistiques et dynamiques.Nous trouvons des anomalies de temprature dans la stratosphre tant durant les annes d'El Nio que de La Nia.Ces anomalies exhibent diverses configurations de distribution, que nous attribuons aux diffrentes chelles des ondes plantaires.Durant un hiver d'El Nio, les ondes plantaires sont plus actives en dcembre et janvier, ce qui engendre davantage de perturbations du tourbillon polaire stratosphrique et une frquence plus leve d'vnements de rchauffement stratosphrique soudain (RSS).Qui plus est, en nous basant sur le flux tridimensionnel d'Eliassen-Palm (E-P), nous trouvons que l'action principale des ondes se produit dans l'hmisphre oriental et dplace le tourbillon polaire vers l'hmisphre occidental.Ces dplacements de tourbillons sont troitement lis aux conditions mtorologiques et climatiques dans les rgions correspondantes.En revanche, durant un hiver de La Nia, les ondes plantaires sont surtout actives en fvrier et mars, et la plupart des vnements de RSS se produisent cette mme poque.La distribution du flux d'E-P indique que les fluctuations des ondes plantaires ont lieu entre 90E et 180E, ce qui entraine un dplacement du tourbillon polaire avec quelques changements conscutifs dans la circulation atmosphrique associe.De plus, la circulation rsiduelle (CR) msosphrique s'inverse entre fvrier et mars, tant durant les annes d'El Nio que de La Nia.Les analyses dynamiques utilisant des ondes de gravit paramtrises montrent que la CR msosphrique mridionale est troitement lie la rsistance due aux ondes de gravit.Ce facteur, son tour, est directement influenc par les configurations de temprature et de vent zonal au dbut et la fin de l'hiver lors des
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".