Photostationary state deviation–estimated peroxy radicals and their implications for HO<sub><i>x</i></sub> and ozone photochemistry at a remote northern Atlantic coastal site
Bibliographic record
Abstract
Measurements of NO, NO2, O3, and ultraviolet irradiance made at Cape Norman, Newfoundland (51.6°N, 55.9°W), during February–April 1996 were used to examine peroxy radical photochemistry and the local photochemical ozone tendency. Deviations from NO‐NO2‐O3 photostationary state (the PSSD method) were used to estimate peroxy radical (PO2) mixing ratios. Potential biases in the PSSD method and the methods used to apply it in an unbiased manner are discussed. PO2 levels reached 77 ± 8 pptv (midday mean ±2σ of the mean), significantly higher than observed in previous studies at remote marine locations. [PO2] was well correlated with ( )1/2, indicating that the dominant radical source was photolysis by ultraviolet radiation in the wavelength region of O3 photolysis and the dominant sink of PO2 was recombination. However, the variation of [PO2] with ( )1/2 (d[PO2]/d( )1/2) was significantly higher than expected at this site during spring. Significant radical production in addition to that from net O3 photolysis, possibly related to snow photochemistry in the upwind region, is suggested as the cause. However, the measurements needed to test this hypothesis were not made in this study, and we suggest future HOx measurements in remote midlatitude, snow‐covered regions. The net photochemical ozone production at this site during springtime was calculated to be minimal (generally small and negative, and always less than or equal to +0.1 ppbv/h). These small values indicate that in situ photochemical ozone production is negligible at this site during spring; if [HO2]/[PO2] is large, net ozone destruction may contribute up to ∼10% of mean ozone levels per day.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".