Descent of deep stratospheric intrusions during the IONS August 2006 campaign
Bibliographic record
Abstract
Deep stratosphere‐to‐troposphere transport (STT) conveying ozone‐rich stratospheric air to the lower troposphere in the extratropics can episodically increase ozone concentrations in the lower troposphere. However, dynamical aspects of the descent, including dispersion and mixing with the surrounding tropospheric air and necessary conditions for reaching the lower troposphere, are not clearly understood yet. This study focuses on August 2006, as daily balloon sonde measurements were made from many sites covering North America within the Intercontinental Chemical Transport Experiment Ozonesonde Network Study campaign. During this period, four profiles were found with clear signs of deep STT. A mesoscale model was used together with trajectory calculation to represent these events. Over 10 days, 20 distinct clusters of trajectories were identified as significant deep STT events, including three observed. The four largest clusters carried 41, 35, 25, and 16 × 1012 kg of mass of air, respectively. A dynamical analysis was performed on the three observed events that were captured numerically. The descents showed three distinct phases: (1) crossing of the tropopause, (2) free descent, and (3) quasi‐horizontal dispersion in the lower troposphere. Clusters are rapidly sliding down sloping isentropes while being slowly diabatically cooled (approximately −1 K d−1). The tilt in the isentropes along the descent is due to an approximately equal combination of a negative potential temperature anomaly at the tropopause during phase 1 and a nearby baroclinic zone at the ground. The combination of these two conditions appears to be necessary for reaching the lower troposphere. In the three cases, the clusters stayed compact until they reach the lower troposphere, and it is estimated that approximately 80% of the ozone of stratospheric origin is released directly in the lower troposphere.
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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 | 0.000 | 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 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".