Nadir measurements from ACE of column amounts of atmospheric gases
Bibliographic record
Abstract
The feasibility of using nadir observations to make column measurements of several stratospheric gases will be evaluated for the Atmospheric Chemistry Experiment (ACE) Fourier-transform spectrometer (FTS), which is scheduled for launch in 2002 on the SCISAT-1 platform. The measurement technique is based on using FTIR spectroscopy to measure the atmospheric absorption of cold gases below the satellite against the thermal emission background from the warm Earth. The FASCOD3 and MODTRAN4 transmission codes are used to simulate the background emission spectra above the Earth; the measured spectra are processed to yield the column concentration of a particular gas in the atmosphere. The gases that can be successfully measured with this technique include ozone, carbon dioxide, carbon monoxide and nitrous oxide. This technique will be demonstrated for nadir IMG spectra obtained in 1997 at a resolution of 0.1 cm/sup -1/. Since ACE points at the Sun throughout its orbit, even when the Earth is in the way, nadir FTS measurements will automatically be taken in addition to the occultation measurements, if enough power is available. A nadir observation will consist of 100 co-added scans at a resolution of 0.4 cm/sup -1/, which will require a total time of 16 seconds and achieve a signal-to-noise ratio of 80:1. Using the spectroscopic structure obtained from nadir IMG spectra at a resolution of 1 cm/sup -1/ over an extended spectral interval, it will be demonstrated that a signal-to-noise ratio of 50:1 gives ozone columns with an error of less than 2%.
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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 | 0.000 | 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) | 0.002 | 0.001 |
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".