Potential source regions and processes of the aerosol in the summer Arctic
Bibliographic record
Abstract
Abstract. Sub-micrometer particle size distributions measured during four summer cruises of the Swedish icebreaker Oden 1991, 1996, 2001, and 2008 were combined with concurrent gas data, back trajectories and daily maps of pack ice cover in order to investigate source areas and aerosol formation processes of the boundary layer aerosol in the central Arctic. With a clustering algorithm potential aerosol source areas were explored. Clustering of particle size distributions together with back-trajectories delineated five potential source regions and three different aerosol types that covered most of the Arctic basin. Clustering the open water information along the trajectories clearly separated marine from pack ice aerosol. Clustering the two subpopulations above and below the 50% value of average open water during the course of the trajectories yielded further details about marine and pack ice aerosol sources. In the pack ice subpopulation three potential source areas over the pack ice with very low percentages of open water from which aged aerosol with only one major mode around 40 nm derived. A significant difference between newly formed and aged aerosol over the pack ice became clear when comparing the course of open water under the trajectories for these two aerosol types. In both subpopulations the air had spent ten days over pack ice with less than 50% open water while traveling over ever more contiguous ice. Trajectories connected with high concentrations of newly formed small particles, however, experienced more open water during the last four days before arrival in heavy ice conditions at Oden. Thus we hypothesize that both, long travel times over the more contiguous ice, combined with more open water conditions during the last days before air mass arrival were an essential factor controlling the formation of ultrafine particles over the central Arctic pack ice. A comparison the Oden data with summer size distribution data from Alert, Nunavut and Mt. Zeppelin, Spitsbergen confirmed the Oden findings with respect to particle sources over the central Arctic.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".