Spectral characteristics of UHF radar aurora
Bibliographic record
Abstract
Radar observations at 440 (Millstone Hill) and 933 MHz (European Incoherent Scatter (EISCAT)) and at both small and large magnetic aspect angle have been used to study the spectral characteristics of backscatter from the auroral E region. The predominantly single‐peaked power spectra were found to have very similar shapes at both frequencies and at both small and large aspect angle. Spectral moments were estimated directly from the autocorrelation functions (ACFs) and were also characterized in terms of a correlation time (related to spectral width) and a decay exponent which quite accurately described the observations. For the most part, spectral shapes were found to be intermediate between Gaussian and Lorentzian, at both large and small magnetic aspect angles. Similar ACF shapes have been observed at much larger wavelengths at HF [ Villain et al., 1996 ], suggesting that this may be a widespread and possibly fundamental characteristic of radar auroral backscatter. In addition to confirming and extending a number of previous observations on UHF spectral characteristics, correlation times were found to decrease sharply near an aspect angle of 3°, having a nearly constant value at all larger aspect angles. This behavior is consistent with a simplified picture of the energy balance for these large aspect angle waves.
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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 | 0.000 | 0.000 |
| 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".