Seasonal variations in <sup>35</sup>S and Δ<sup>17</sup>O of sulfate aerosols on the Antarctic plateau
Bibliographic record
Abstract
Abstract The first reported seasonal Δ 17 O anomaly in sulfate aerosols and measurements of radioactive 35 SO 4 2− activities collected from Dome C, Antarctica, are reported. Δ 17 O values exhibit minima during summer (as low as 0.91‰) when tropospheric oxidation patterns are dominated by OH/H 2 O 2 mechanisms. Significant enrichment during autumn and spring is observed (up to 2.40‰) as ozone oxidation increases in the troposphere relative to summer and both stratospheric sources and long‐range transport become more significant to the total sulfate budget. An unexpected decrease in Δ 17 O is seen as winter progresses. This decline is concluded to potentially arise due to a reduction in vertical mixing in the troposphere or linked to variations in the long‐range transport of sulfur species to Antarctica. 35 SO 4 2− activities exhibit maxima during summer (up to 1219 atoms 35 S/m 3 ) that correlate with the peak in stratospheric flux and minima during winter (as low as 146 atoms 35 S/m 3 ) when the lack of solar radiation substantially reduces photochemical activity. It is shown that 35 S offers the potential to be used as an additional tracer to study stratospheric and tropospheric interactions and is used to estimate stratospheric input of sulfur (combination of SO 2 and SO 4 2− ). Stratospheric sulfur input produces maxima during summer/autumn with an upper limit of 5.5 ng/m 3 and minima during winter/spring with an upper limit of 1.1 ng/m 3 . From these results, it is concluded that the variation in Δ 17 O is more reliant upon shifts in tropospheric oxidation mechanisms and long‐range transport than on changes in the stratospheric flux.
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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 | 0.001 |
| 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 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 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".