Can an Earth Gravitational Model Augmented by a Topographic Gravity Field Model Realize the International Height Reference System Accurately?
Bibliographic record
Abstract
Abstract In this study, we evaluate the suitability of recent Earth Gravitational Models (EGMs) for the realization of the International Height Reference System (IHRS) in Canada. Topographic gravity field models have been used to augment EGMs to spatial resolution reaching 2′ (about 4 km), which is comparable to regional geoid models. The advantages of using an EGM over a regional approach for the IHRS are its uniform representation of the Earth’s gravity field and its conformance to international standards and conventions. The main challenge is access to, and best use of knowledge of the regional gravity and topographic data. On the one hand, we determine that two recent hybrid models (EIGEN-6C4 and XGM2019) augmented by topographic signals give geopotential values (W p ) with accuracy of ~0.3 m2 s−2, which is close to those estimated by the Canadian regional geoid models at the 11 International Height Reference Frame sites in Canada. On the other hand, two recent augmented satellite-only models (DIR-R6 and GOCO06s) give W p with accuracies between 1.5 and 1.7 m2 s−2 in Canada.
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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 | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".