Sulphur isotopic composition of aerosols over the western North Atlantic Ocean
Bibliographic record
Abstract
During spring (1998) and fall (1999) cruises of the Northern Oceans Dimethylsulphide (DMS) Emissions Model programme (NODEM II and III), size-segregated atmospheric aerosol samples were collected above the western North Atlantic Ocean. The soluble portion of the aerosols was analyzed for concentrations of sulphate, sodium, nitrate, and methane sulphonic acid (MSA). Sulphur isotopic compositions were measured on total soluble sulphur. The stable isotope data conform to a mixing model involving contributions from biogenic, anthropogenic, and sea salt sulphur sources. Biogenic sulphur fractions calculated using stable isotopic compositions range from 0.00 to 0.64 of the total sulphate, higher than most previously reported values. %MSA/NSS (non-sea-salt) SO42 ranges from 0 to 94. The data suggest that sulphates of clearly biogenic origin (MSA) are formed in areas where surface-ocean DMS concentrations are high. These sulphates contribute to aerosol mass in particles up to 3 µm in diameter. This seems to occur by condensation onto existing aerosols. Stable isotope data indicate that these existing aerosols can be of either biogenic or anthropogenic origin depending on the size fraction and geographic location. Stable isotope data also reveal other areas where sulphate aerosols of biogenic origin are produced, not associated with MSA.
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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 | 0.001 | 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".