Stratospheric composition measurements in the arctic and at mid-latitudes and comparison with chemical fields from atmospheric models
Bibliographic record
Abstract
The purpose of this research is to contribute to our understanding of the processes determining the Arctic stratospheric ozone budget by deploying an ultraviolet-visible spectrometer at the Arctic Stratospheric Ozone Observatory (ASTRO) located at Eureka, NU (80.1°N, 86.4°W). For four years, O 3 columns, NO2 vertical columns and profiles, and OCIO slant columns (in 2000) were measured during polar spring. The spectrometer was also deployed in Vanscoy, SK (52°N, 107°W) in 2000 and 2002 as part of the Middle Atmosphere Nitrogen TRend Assessment (MANTRA) project. The resulting O3 columns were compared with Brewer, TOMS and GOME data. The NO 2 columns, NO2 reference column density (RCD) and NO 2 diurnal variability were also determined. The Arctic measurements were analysed in detail and combined with infrared Fourier transform spectrometer measurements at ASTRO and with HNO3 measurements at Thule, Greenland (76.5°N, 68.8°W) and Kiruna, Sweden (67.8°N, 20.4°E) (in 2001-2002). To assess the chemical fields of atmospheric models, the observational data set was compared with chemical fields from the Canadian Middle Atmosphere Model (CMAM) and SLIMCAT, a 3D Chemical Transport Model. The comparison of CMAM with measurements made during the warm Arctic winters (1999, 2001, 2002 and 2003) provided an excellent opportunity to test the model simulations under PSC-free conditions. Generally, the CMAM inter-annual variability is small and does not fully cover the range of the observed variability. SLIMCAT O3 columns were generally higher than the observed values. Comparison with O3 profiles from sondes indicated that O3 mixing in the lower stratosphere was too fast in SLIMCAT. A sensitivity study on the contributions of NO2 RCD uncertainty to the retrieval of NO2 profiles showed that a 10% uncertainty in the RCD changes the retrieved profile by 5-10% at northern high latitudes. This project extended the temporal-geographical range of polar stratospheric observations and strengthened Canadian capabilities in monitoring the mid-latitude and particularly the Arctic stratosphere. As part of an ongoing research program, it will provide a long-term data set in the Canadian High Arctic, which can be used for future trend analysis.
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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 | 0.000 | 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".