On the changing abundance of ozone minima at northern midlatitudes
Bibliographic record
Abstract
An analysis of ozonesonde data for stations whose records go back at least a quarter of a century suggests that the number of intrusions of subtropical air into the midlatitude lower stratosphere has recently increased. These air masses, referred to here as ozone minima, contain low ozone concentrations over vertical depths of ∼4 km, sufficient to reduce the total ozone column by 10–15%. The mixing ratios of other trace species, such as nitrous oxide (N2O), carbon monoxide (CO), and water vapor (H2O) recorded in midlatitudes by the NASA ER‐2 aircraft, suggest that these intrusions originate either in the lower tropical stratosphere or in the upper tropical troposphere. Potential vorticity calculated from the European Centre for Medium‐Range Weather Forecasts (ECMWF) and National Center for Environmental Prediction (NCEP) date, have been used in conjunction with TOMS total ozone data to estimate the typical area covered by minima. Their contribution to the midlatitude ozone trend is discussed. TOVS data have also facilitated the identification of a prominent ozone minima source region in the subtropical western Atlantic, where the Atlantic storm track is particularly intense. Minima frequently advect over Europe, explaining the high abundance of these events observed by European ozonesonde stations, relative to ozonesonde data from Canada.
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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) | 0.002 | 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".