Validation of ACE-FTS measurements of CFC-11, CFC-12 and HCFC-22 using ground-based FTIRs
Bibliographic record
Abstract
Satellite data can be an effective global monitoring tool for long-lived compounds in the atmosphere. The Atmospheric Chemistry Experiment (ACE) is a mission onboard the Canadian satellite SCISAT. The primary instrument on SCISAT is a high-resolution infrared Fourier transform spectrometer (ACE-FTS) which is capable of measuring a range of gases including key chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) species. These families of species are of interest because of their significant contribution to anthropogenic ozone depletion and to global warming. To assess the quality of data derived from satellite measurements, validation using other data sources is critical. Ground-based Fourier transform infrared spectrometers (FTIRs) are particularly useful for this purpose. In this study, five FTIRs located at four sites around the world are used to validate the CFC-11 (CCl3F), CFC-12 (CCl2F2), and HCFC-22 (CHClF2) retrieved profiles from ACE-FTS measurements. These species are related because HCFC-22 was the primary replacement for CFC-11 and CFC-12 in refrigerant and propellant applications. The FTIRs used in this study record solar absorption spectra at Eureka (Canada), Jungfraujoch (Switzerland), Poker Flat (USA), and Toronto (Canada). The retrieval of CFC-11, CFC-12, and HCFC-22 are not standard products for many of these FTIRs, and as such, a harmonization of retrieval parameters between the sites has been conducted. The retrievals of these species from the FTIR spectra are sensitive from the surface to approximately 20 km, while the ACE-FTS profiles extend from 6 to 30 km. For each site, partial column comparisons between coincident measurements of the three species and a validation of the observed trends will be discussed.
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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 | 0.000 | 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 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".