Middle- and High-Latitude Mesosphere and Lower Thermosphere Mean Winds and Tides in Response to Strong Polar-Night Jet Oscillations
Bibliographic record
Abstract
The dynamical behavior of the mesosphere and lower thermosphere (MLT) region during strongly disturbed wintertime conditions commonly known as polar-night jet oscillations (PJOs) is described in detail and compared to other wintertime conditions. For this purpose, wind measurements provided by two specular meteor radars located at Andenes (69°N, 16°E) and Juliusruh (54°N, 13°E) are used to estimate horizontal mean winds and tides as an observational basis. Winds and tidal main features are analyzed and compared for three different cases: major sudden stratospheric warming (SSW) with (a) strong PJO event, (b) non-PJO event, and (c) no major SSWs. We show that the distinction into strong PJOs, non-PJOs, and winters with no major SSWs is better suited to identify differences in the behavior of the mean winds and tides during the boreal winter. To assess the impact of the stratospheric disturbed conditions on the MLT region, we investigate the 30-year nudged simulation by the Extended Canadian Middle Atmosphere Model. Analysis of geopotential height disturbances suggests that changes in the location of the polar vortex at mesospheric heights are responsible for the jets observed in the MLT mean winds during strong PJOs, which in turn influence the evolution of semidiurnal tides by increasing or decreasing their amplitudes depending on the tidal component. © 2019. The Authors.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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; a candidate call from one teacher head, not a consensus.
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".