Upwelling into the lower stratosphere forced by breaking tropical waves: evidence from chemical tracers
Bibliographic record
Abstract
Abstract. Measurements from the Microwave Limb Sounder (MLS) on the 68 hPa pressure level from 1 January 2005 to 31 December 2010 are used to calculate the coherence between anomalies in the tropical mean mixing ratios of H2O, CO, and N2O, and 100 hPa temperature. We show that the fluctuations of lower stratospheric water vapor in the subseasonal and multiyear time windows are generated by different physical mechanisms. In the subseasonal time window, the spatial pattern of the coherence between 100 hPa temperature and water vapor, and the time lag, show that the variability in lower stratospheric water vapor is dominated by fluctuations in upwelling forced by the dissipation of tropical Rossby waves. In the multiyear time window, the variability of lower stratospheric water vapor is more strongly coherent with temperature fluctuations on the 100 hPa surface in regions where the annual mean temperature is colder than 194 K. In addition, the 68 hPa water vapor anomalies lag the 100 hPa temperature anomalies by roughly 140 days. In this time window, the variability of lower stratospheric water vapor is therefore dominated by changes in the temperature dependent dehydration efficiency which modulate the water vapor stratospheric entry mixing ratio. On subseasonal timescales, the spatial pattern of the coherence between 100 hPa temperature and 68 hPa CO anomalies is very similar to the pattern of coherence between 100 hPa temperature and the Real-time Multivariate MJO series 1 (RMM1) index of the Madden Julian Oscillation (MJO). The MJO therefore has a strong influence on the subseasonal variability of CO in the lower stratosphere. The subseasonal 68 hPa CO and H2O anomalies lag the 100 hPa temperature anomalies by 3.16 and 2.51 days, respectively. The similarity between the two time lags suggests that the subseasonal CO anomalies can also be attributed to changes in upwelling. The multiyear variability in lower stratospheric N2O appears to be dominated by the Quasi Biennial Oscillation (QBO).
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".