Study of the electron density in the high latitude ionosphere with incoherent scatter radars and Swarm satellites
Bibliographic record
Abstract
Despite century-long efforts in assessing the electron density distribution in the Earth’s ionosphere and significant progress in identification of its major features, there are still many uncertainties with respect to the solar cycle’s seasonal and diurnal trends at various latitudes. Knowledge of these variations is needed for robust forecasting of the state of the ionosphere for the operation of practical radio systems, for example communication via high frequency radio waves. This thesis utilizes data from the incoherent scatter radar (ISR) at Poker Flat (Alaska, USA) to assess the diurnal and seasonal variations of three parameters of the ionospheric F2 region, the peak density, the height of the peak, and the thickness of the layer. These parameters are assessed for relatively high solar activity in 2014, and relatively low solar activity in 2016. Daytime electron densities were found to be largest during winter and spring and nighttime electron densities were found to be smallest in winter. Electron densities during the higher solar activity year were found to be greater than those during the lower solar activity year by a factor of 2-5, depending on the time of day, as expected. Details of the diurnal variations in electron density for various seasons are further discussed. ISR electron density data are also used for the validation of electron density measurements from Langmuir probes onboard the Swarm satellites in the topside ionosphere (~500 km). This work is an expansion of previous studies that use a different mode of ISR operation and a different approach to both ISR and Swarm satellite data handling. In addition to observations over Poker Flat (geographic latitude of ~60° N), observations over Resolute Bay, Canada at extreme high latitudes of ~80° are also considered. It is shown that, overall, the ratio of Swarm electron density measurements to those measured by ISRs is ~0.5-0.6 and that smaller ratios are observed at larger electron densities, usually during the daytime. At low electron densities less than 3∙1010 m-3 , the ratios are typically greater than 1, indicating an overestimation effect. The overestimation effect is stronger at night and at higher altitude. It is also more evident during lower solar activity when the electron density in the topside ionosphere is smaller. The conclusions on the electron density underestimation and overestimation by the Swarm Langmuir probes are overall consistent with previous reports, but this thesis confirms that these effects also occur at high latitudes.
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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".