Evaluation of the GRACE-based global gravity models in Canada
Bibliographic record
Abstract
Four GRACE-based gravity models, especially EGM08, have been evaluated using the surface gravity observations, GPS-levelling, deflections of the vertical, and the recent Canadian gravimetric geoid CGG05. The RMS of the differences between the EGM08-predicted gravity anomalies and the observed anomalies is smaller than 5 mGal on sea and lake surfaces, in contrast to about 14 mGal on land in Canada. The RMS increases with increasing elevation on land, exhibiting an evident height-dependent trend, while the RMS decreases with increasing depth on sea and lake surfaces, without a significant trend. The GPS-levelling comparisons suggest that EGM08 models the geoid with an accuracy of 10 cm or better in Canada. It is comparable with the Canadian Gravimetric Geoid 2005 (CGG05). Recent releases of GRACE models show noteworthy improvement over earlier ones. The comparisons between the EGM08-predicted and astronomical deflections of the vertical show the RMS of 1.8 arc-seconds in the north-south direction, and 2.1 arc-seconds in the east-west direction, which are significantly larger than the RMS of differences between the CGG05-predicted and astronomical deflections .
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".