Transport of Biomass Burning Aerosol into the Extratropical Tropopause Region over Europe via Warm Conveyor Belt Uplift
Bibliographic record
Abstract
We present measurements from the aircraft-based TPEx (Tropopause composition gradients and mixing Experiment) mission in June 2024 over Europe. The measurement platform, a Learjet 35A, was equipped with in-situ trace gas and aerosol measurements and filter samplers for offline analysis. For vertical gradient measurements of trace species and aerosol, we conducted redundant measurements on a fully automated towed sensor shuttle (TOSS) 200 m below the aircraft. On 17 June 2024, we observed a filament with elevated aerosol number concentrations of up to 800 particles cm −3 between 100 nm and 1 µm. This is higher by a factor of two to four than the local background. Carbon monoxide (CO) mixing ratios were larger than 100 ppbv. Single particle analysis of impactor samples using electron microscopy show characteristic biomass burning (BB) aerosol in the tropopause region. The TOSS measurements also allow the calculation of the potential temperature gradient (Δθ⋅Δz-1). Within the polluted filament, we observe changes towards smaller gradients, which is presumably due to an increase of potential temperature at lower altitudes by radiative heating as a consequence of the transported BB aerosol. Trajectory analysis show air mass origin over Canada with low-level long-range transport and subsequent uplift by a warm conveyor belt (WCB) over Europe as additional pathway of pollution into the UTLS. Furthermore, this analysis yields that BB aerosol can be transported in a WCB into the UTLS there it can be mixed with stratospheric air masses.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 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".