Discrepancy between the nighttime molecular ion composition given by the International Reference Ionosphere model and airglow measurements at low latitudes
Bibliographic record
Abstract
The 630‐nm nighttime airglow is radiated by O( 1 D ) atoms, which are produced by the dissociative recombination of O 2 + ions. The typical approach used to calculate the red line emission rate at night is based on the assumption that O 2 + is mainly produced by the reaction of O + with molecular oxygen. In the case that the O 2 + density is much smaller than the O + density, [O + ] = n e in the F 2 region. Good agreement between measured nighttime integrated emission rates and the emission rates calculated by this typical approach, using both electron densities measured by incoherent scatter radars and given by the International Reference Ionosphere (IRI) model, has been shown. However, the O 2 + densities given by the IRI model are much higher than the densities produced by the reaction of O + with O 2 , and these densities do not correspond to the condition [O + ] = n e . In this case, the typical approach cannot be applied and molecular ions must be included in the emission rate calculations. The integrated emission rates calculated including the molecular ion density given by the IRI model have been found to be much higher than the measured 630.0‐nm emission rates. This discrepancy takes place at latitudes below about ±30° in the western longitude sector, mainly for the period from March to November, and the disagreement is higher than 1 order of magnitude at the equator. In addition, we model the F 2 region green line O( 1 S ) emission at 557.7 nm resulting from the dissociative recombination of O 2 + . Using measurements of this volume emission rate made by the Wind Imaging Interferometer (WINDII) satellite, we are able to show that IRI overestimates the O 2 + density (and ion fraction) on the bottomside of the F 2 region. A revision of the ion composition in the IRI model on the bottomside seems to be needed on the basis of these results. Airglow measurements may be useful in constraining such a revision. A revision could utilize the formulae for the relationship between the molecular ion densities and neutral densities derived here, using the Mass Spectrometer Incoherent Scatter (MSIS) neutral densities and the IRI electron density. These calculations are based on the assumption that O 2 + and NO + are only produced through ion‐molecular reactions. Such a revision would correct the magnitude and altitudinal dependence of the molecular ion fraction in the IRI model.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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".