Comparison of mesospheric sodium profile retrievals from OSIRIS and SCIAMACHY nightglow measurements
Bibliographic record
Abstract
Sodium airglow is generated when excited sodium atoms emit electromagnetic radiation while they are relaxing from an excited state into a lower energetic state. This electromagnetic radiation, the two sodium D lines at 589.0 and 589.6 nm, can usually be detected from space or from ground. Sodium nightglow occurs at times when the sun is not present and excitation of sodium atoms is a result of chemical reaction with ozone. The detection of sodium nightglow can be a means to determine the amount of sodium in the earth's mesosphere and lower thermosphere (MLT). In this study, we present time series of monthly mean sodium concentration profiles, by utilizing the large spatial and temporal coverage of satellite sodium D-line nightglow measurements. We use the OSIRIS/Odin mesospheric limb measurements to derive sodium concentration profiles and vertical column densities and compare those to measurements from SCIAMACHY/Envisat and GOMOS/Envisat. Here we show that the Na D-line limb emission rate (LER) and volume emission rate (VER) profiles calculated from the OSIRIS and SCIAMACHY measurements, although the OSIRIS LER and VER profiles are around 25 % lower, agree very well in shape and overall seasonal variation. The sodium concentration profiles also agree in shape and magnitude, although those do not show the clear semi-annual cycle which is present in the LER and VER profiles. The comparison to the GOMOS sodium vertical column densities (VCDs) shows that the OSIRIS VCDs are of the same order of magnitude although again the semi-annual cycle is not as clear. We attribute the differences in the LER, VER and sodium profiles to the differences in spatial coverage between the OSIRIS and SCIAMACHY measurements, the lower signal-to-noise ratio (SNR) of the SCIAMACHY measurements and differences in local time between the measurements of the two satellites.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".