Transpacific transport of benzo[a]pyrene emitted from Asia
Bibliographic record
Abstract
Abstract. A global-scale three dimensional atmospheric transport and chemistry model was applied to simulate transpacific transport of Benzo[a]pyrene (BaP) emitted from Asia. The model results were compared with observations at six monitoring sites. The annual mean and seasonal variation of transport patterns and the contributions of different Asian source regions to transpacific transport flux were investigated. The episodic nature of transpacific transport was also systematically explored. Interannual variability of transpacific transport of BaP was also assessed during the period of 1948–2007. Results showed that strong enhancements of modeled BaP occurred in an area bounded by 70–80° E and 100–120° E. Air containing these elevated BaP concentrations was then delivered eastward by westerly winds. When approaching the West Coast of North America, the descending atmospheric motion carried BaP-laden air into the lower atmosphere. The transpacific transport flux was 1.6 times higher in the winter than in the summer. East Asian emission dominates the transpacific transport flux with a contribution of about 97%. Near ground concentration of BaP induced by Asian sources in North America varied between 1–20 pg m−3. A case study for observation at Cheeka Peak Observatory during March 2002–May 2002 reveals the importance of warm conveyor belt for transpacific transport. The number of days with transpacific transport flux with a factor of 0.5, 1.0, 1.5, and 2.0 larger than the running mean were 9.4%, 0.72%, 0.06% and 0.01%, respectively, implying a mild contribution of episodic transport to the long-term mean transport flux. Significant interannual fluctuation of transpacific transport of BaP was found, including a general decreasing trend during 1948–2007, and especially after the 1970s. The transpacific transport was found to be positively correlated with the Southern Oscillation Index.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".