Particulate trimethylamine in the summertime Canadian high Arctic lower troposphere
Bibliographic record
Abstract
Abstract. Size-resolved and vertical profile measurements of single particle chemical composition (sampling altitude range 50–3000 m) were conducted in July 2014 in the Canadian high Arctic during the aircraft-based measurement campaign NETCARE 2014. We deployed the single particle laser ablation aerosol mass spectrometer ALABAMA (vacuum aerodynamic diameter range approximately 200–1000 nm) to identify different particle types and their mixing states. On basis of the single particle analysis, we found that a significant fraction (23 %) of all analyzed particles (in total: 7412) contained trimethylamine (TMA). The identification of TMA in ambient mass spectra was confirmed by laboratory measurements. From the maximum occurrence of particulate TMA in the Arctic boundary layer and the higher abundance of smaller TMA-containing particles (maximum in the size distribution at 300 nm), we conclude that the TMA component of these particles resulted from emissions within the Arctic boundary layer. Air mass history according to FLEXPART backward simulations and associated wind data give evidence of a marine-biogenic influence on particulate TMA. The marine influence on particle chemical composition in the summertime Arctic is further demonstrated by the existence of larger sodium and chloride (Na/Cl-) containing particles which are mainly abundant in the boundary layer. Some of these sea spray particles were internally mixed with carbohydrates (e.g., cellulose) which likely originated from a sea surface microlayer enriched with microorganisms and organic compounds. The external mix of sea spray particles and TMA-containing particles suggests the latter result from secondary conversion of precursor gases from marine inner-Arctic sources. In contrast to TMA- and Na/Cl-containing aerosol types, particles with biomass-burning markers (such as levoglucosan) showed a higher fraction at higher altitudes, thereby indicating long-range transport as their source. Our measurements highlight the importance of natural, marine inner-Arctic sources for summertime Arctic aerosol.
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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 | 0.001 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 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".