AIRS Satellite Observations of Gravity Waves During the 2009 Sudden Stratospheric Warming Event
Bibliographic record
Abstract
Abstract A major sudden stratospheric warming event occurred on January 24, 2009 and showed a unique and pronounced planetary wave 2 amplitude with a subsequent split in the polar vortex. While research about the role of planetary waves during sudden stratospheric warming events exists, the contribution of gravity waves (GWs) is still uncertain. We therefore investigated the role of stratospheric GWs in the Northern Hemisphere during the 2009 winter season. We use observational data from NASA's Atmospheric Infrared Sounder (AIRS) satellite instrument for our analysis. Variances in the 4.3 µm brightness temperature perturbations are analyzed together with Level 3 temperature retrievals to investigate the connection between GWs and the warming event. Our planetary wave analysis shows zonal wavenumber 1 amplitudes during December 2008 and early January 2009. However, zonal wavenumber 2 is more dominant between mid‐January and January 24, 2009. We also found a decrease in Northern hemisphere GW activity a few days before the maximum warming and the wind reversal occur at 30 hPa altitude. Furthermore, prominent GW activity was found at Labrador Peninsula and southern Greenland, both are locations of elevated GW activity (hotspots), until mid‐January 2009. We discuss the potential of these orographic GWs to amplify planetary waves during the onset of the sudden stratospheric warming (SSW) event.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".