Simultaneous Measurements of Temporal and Spatial Phase Structure Functions of an HF Skywave Signal at Mid-Latitudes
Bibliographic record
Abstract
This paper presents the results of data collected with an HF/VHF interferometer in southern Maryland of skywave propagating signals from WWV near Ft. Collins, Colorado and CHU near Ottawa, Ontario. Using a four-antenna array with spacings of ~100-350 m near Pomonkey, Maryland, a four-hour test data collection was made of the 10 MHz signal from WWV in Feb. 2020. Measurements of the temporal and spatial phase structure functions (SFs) from this collection were used to constrain the coherence time and length as well as the relationship between the two. The temporal SFs indicated coherence times of ~1-4 s. By scaling the temporal SFs to match the spatial ones, it was found that the ratio of coherence length (on the ground) to coherence time was about $\sim$200 m s-1 until near sunset when this ratio became highly variable and was ~400-800 m s-1. A 30-day campaign in Oct. 2022 that used two of the four antennas to collect data from the 7.85 MHz skywave of CHU yielded similar results. These showed the coherence ratio systematically increasing from ~150 m s-1 at 17 UT (noon local time) to ~250 m s-1 at 22 UT (17 local time).
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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) | 0.000 | 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".