Observations of 50‐ and 12‐MHz auroral coherent echoes at the Antarctic Syowa station
Bibliographic record
Abstract
Data on 50‐ and 12‐MHz E region coherent echoes from approximately the same directions and in a broad range of azimuths are available for 1995–1997 radar observations at the Antarctic Syowa station. One event of such observations is considered to compare power and Doppler velocity of echoes at these significantly different frequencies. For the considered event, Doppler velocities of more than 600 ms−1 (as recorded at both radar frequencies) were observed. We show that even though the 50‐MHz echoes exhibit strong flow angle variation of the power, the 12‐MHz echoes do not. Apparent aspect angle power attenuation is found to be 10 and 2.5 dBdeg−1 at 50 and 12 MHz, respectively. Measured Doppler velocities along specific radar directions are found to be comparable in spite of the significant difference in radar frequencies, with the velocity ratio V50MHz/V12MHz being in between 1.6 and 0.9 for high velocities of more than 400 ms−1. The velocity ratio varies with slant range and azimuth of observations. Ionospheric propagation effects for radio waves and plasma physical effects for irregularities are considered in an attempt to explain several observed features, for example, the echo power and velocity ratio variations with slant range.
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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 | 0.001 | 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".