Nitric acid measurements at Eureka obtained in winter 2001–2002 using solar and lunar Fourier transform infrared absorption spectroscopy: Comparisons with observations at Thule and Kiruna and with results from three‐dimensional models
Bibliographic record
Abstract
For the first time, vertical column measurements of nitric acid (HNO3) above Eureka (80.1°N, 86.4°W), Canada, have been made during polar night using lunar spectra recorded with a Fourier transform infrared (FTIR) spectrometer, from October 2001 to March 2002. This site is part of the primary Arctic station of the Network for the Detection of Stratospheric Change. These measurements were compared with FTIR measurements at two other Arctic sites: Thule, Greenland (76.5°N, 68.8°W), and Kiruna, Sweden (67.8°N, 20.4°E). Eureka lunar measurements are in good agreement with solar ones made with the same instrument. Eureka and Thule HNO3 columns are consistent within measurement error. Differences between HNO3 columns at Kiruna and those at Eureka and Thule can be explained on the basis of available sunlight hours and location of the polar vortex. The measurements were also compared with results from a chemistry‐climate model, the Canadian Middle Atmosphere Model (CMAM), and from a three‐dimensional chemical transport model, SLIMCAT. This is the first time that CMAM HNO3 columns have been compared with observations in the Arctic. The comparison of CMAM HNO3 columns with Eureka and Kiruna data shows good agreement. The warm 2001–2002 winter with almost no polar stratospheric clouds makes the comparison with this version of CMAM, which has a known warm bias, a good test for CMAM under these conditions. SLIMCAT captures the magnitude of HNO3 columns at Eureka, and the day‐to‐day variability, but generally reports higher values than were measured at Thule and Kiruna.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".