Statistical study of midlatitude <i>E</i> region echoes observed by the Hokkaido SuperDARN HF radar
Bibliographic record
Abstract
Abstract Statistical characteristics of short‐range coherent echoes observed by the Hokkaido Super Dual Auroral Radar Network (SuperDARN) high‐frequency (HF) radar (geographic/geomagnetic latitude = 43.5°N/37.3°N) at midlatitudes are investigated. We show that the echo occurrence is increased during nighttime and, especially strongly, during winter and summer. During summer, the occurrence rates are still large during morning‐prenoon hours; for these periods, strong sporadic E layers are observed by the Wakkanai ionosonde (geographic/geomagnetic latitude = 45.2°N/39.1°N) located in the vicinity of the radar field of view. Echo occurrence rate does not increase with the planetary magnetic activity characterized by the Kp and Dst magnetic indices and, seasonally, anticorrelates with variations of the Ap index. With respect to the magnetic L shells, echoes are seen more frequently in beams oriented almost perpendicular to L shells during summer, in beams at intermediate angles during equinoxes and winter, and sometimes in beams at the smallest available angles (~45°) during winter. Midlatitude echoes are of about the same power as at high latitudes but narrower by a factor of ~5. Power and spectral width of nighttime echoes increases with Doppler velocity, consistent with high‐latitude observations. The Doppler velocity shows a clear semidiurnal variation. The local time of these maxima changes with season. It is hypothesised that many Hokkaido echoes are received at high magnetic aspect angles of several degrees, and they are coming from the lower part of the E region where the irregularity phase velocity is affected by both E × B plasma drifts and neutral winds.
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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) | 0.000 | 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".