Standards Development of Global Warming Gas Species: Methane, Nitrous Oxide, Trichlorofluoromethane, and Dichlorodifluoromethane
Bibliographic record
Abstract
Environmental scientists from federal agencies, such as the National Oceanic and Atmospheric Administration (NOAA), and academia have long suspected that increasing anthropogenic inputs of various trace gases into the atmosphere can cause changes in the earth's climate and protective ozone layer. Nitrous oxide and methane, cited in the Kyoto Protocol, as well astrichlorofluoromethane (CFC-11) and dichlorodifluoromethane (CFC-12), cited in the Montreal Protocol, are all greenhouse gases and are implicated in the destruction of the stratospheric ozone layer. The lack of national standards prompted research to determine the feasibility of preparing accurate and stable standards containing these four compounds. Development of these standards would support the measurement of these species by those in the atmospheric research community not having their own source of standards. A suite of eight primary gas standards containing methane, nitrous oxide, CFC-11, and CFC-12 in a balance of air were prepared gravimetrically to bracket the ambient atmospheric concentrations. The combined uncertainties (uc) were calculated from error propagation analysis that included the weighing data from the gravimetric preparation and other sources of error such as the purity analysis of the compounds and air matrix. The expanded uncertainties (U) for the gravimetric standards were < 0.5% as calculated from the equation U = kuc, where the coverage factor k is equal to 2 for a 95% confidence interval. Analyses of the suite of standards by gas chromatography with flame-ionization and electron capture detection resulted in average absolute residuals of < 0.25% from regression models. The NIST suite of eight gravimetric standards was used to determine the concentrations in two standardsfrom NOAA. Those analyses resulted in bias across the two laboratories of < or = 2.1%.
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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 | 0.008 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.003 |
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".