Long‐term stratospheric carbon tetrafluoride (CF<sub>4</sub>) increase inferred from 1985–2004 infrared space‐based solar occultation measurements
Bibliographic record
Abstract
The long‐term stratospheric carbon tetrafluoride (CF 4 ) increase has been determined from infrared high spectral resolution solar occultation Fourier transform spectrometer measurements between 3 and 50 hPa (∼20 to 40 km altitude) and latitudes from 50°N to 50°S during 1985, 1992, 1993, 1994, and 2004. The 1985 to 1994 measurements were recorded from the ATMOS (Atmospheric Trace MOlecule Spectroscopy) instrument at 0.01 cm −1 resolution and in 2004 by the Atmospheric Chemistry Experiment (ACE) instrument at 0.02 cm −1 resolution. Stratospheric volume mixing ratios, inferred from a polynomial fit to averages from the time periods considered here, increased from 49.37 ± 2.60 pptv (10 −12 per unit volume) in 1985 to 58.38 ± 4.14 pptv in 1992, 60.46 ± 2.97 pptv in 1993, 60.11 ± 3.60 pptv in 1994 and to 70.45 ± 3.40 pptv in 2004. The stratospheric CF 4 mixing ratio has continued to increase but at a slower rate than in previous years, for example, (1.14 ± 0.68)% yr −1 in 2004 as compared to (2.77 ± 0.47)% yr −1 in 1985, 1 sigma. Correlations of CF 4 with N 2 O taking into account the increase of N 2 O with time also show the increase in the stratospheric CF 4 burden over the two decade measurement time span. Our space‐based measurements show that the slowdown in the rate of CF 4 accumulation previously reported from surface measurements through 1997 has propagated to the stratosphere and is continuing.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".