Low‐latitude ionospheric <i>D</i> region dependence on solar zenith angle
Bibliographic record
Abstract
Abstract Phase and amplitude measurements of VLF radio signals on a short, nearly all‐sea path between two Hawaiian Islands are used to find the height and sharpness of the lower edge of the daytime tropical D region as a function of solar zenith angle (SZA). The path used was from U.S. Navy transmitter NPM (21.4 kHz) on Oahu to Keauhou, 306 km away, on the west coast of the Big Island of Hawaii, where ionospheric sensitivity was high due to the destructive interference between the ionospherically reflected wave and the ground wave, particularly around the middle of the day. The height and sharpness are thus found to vary from H′ = 69.3 ± 0.3 km and β = 0.49 ± 0.02 km −1 for SZA ~10°, at midday, to H′ > 80 km and β ~ 0.30 km −1 as the SZA approached ~70°–90°, near dawn and dusk for this tropical path. Additional values for the variations of H′ and β with solar zenith angle are also found from VLF phase and amplitude observations on other similar paths: the short path, NWC to Karratha (in NW Australia), and the long paths, NWC to Kyoto in Japan and NAU, Puerto Rico, to St. John's Canada. Significant differences in the SZA variations of H′ and β were found between low and middle latitudes resulting from the latitudinally varying interplay between Lyman α and galactic cosmic rays in forming the lower D region. Both latitude ranges showed β < 0.30 km −1 during sunrise/sunset conditions.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".