Ozone recovery and stratospheric cooling - What can we see from a few long-term stations?
Bibliographic record
Abstract
Thanks to the Montreal Protocol, the decline of stratospheric ozone has been stopped. Ozone has now started to recover. The Kyoto Protocol, however, has been less successful. CO2 levels keep increasing, the stratosphere keeps cooling. Among other things, this cooling does affect ozone recovery. What can data from just a few NDACC stations tell us about these long-term changes? In our presentation we will look at long-term variations of stratospheric ozone and temperature since the 1960s. We will show results from NDACC stations and from Europe, and will put those into the context of global observations. At Hohenpeissenberg (47.8°N, 11.0°E), ozone in the upper stratosphere (40km / 2hPa) has been increasing since about 2000, by almost 10%. Levels are already comparable to what was measured in the late 1980s. At the same time, temperature has been declining substantially since about 2000, by more than 3 K. Total ozone, where variations are coming mostly from the lower stratosphere, has been increasing since the mid 1990s at Hohenpeissenberg. This increase, and the previous decline, largely track the evolution of Equivalent Effective Stratospheric Chlorine (EESC). Superimposed are natural variations, which were particularily large in 2010 and 2011. 2010 had very large ozone columns, comparable to the early 1980s. 2011, on the other hand, was a year with very low ozone columns, and with unprecedented large ozone losses in Arctic spring. At Hohenpeissenberg, the total ozone annual mean of 2011 was the 3rd lowest on record since 1968. Only 1992 and 1993, after the Pinatubo eruption, had lower ozone columns. Multiple linear regression analysis indicates that this large swing from 2010 to 2011 is connected to meteorological changes, i.e. the change of the Arctic Oscillation from pronounced negative phase in 2010, to pronounced positive phase in 2011.
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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 | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.004 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".