NAD83v70VG: a new national crustal velocity model for Canada
Bibliographic record
Abstract
A national-scale crustal velocity model has been developed for Canada as part of the current realisation of NAD83(CSRS), delivered as a set of 3 national grids, for each of the North, East and Up (N, E and U) components. It is used to propagate coordinates to different reference epochs, and to support scientific studies such as natural hazards, climate change, and groundwater change. The previous velocity model was based on continuous and campaign GPS data between 1994 and 2011.3. The new model includes new stations in key areas, six more years of data (to the end of 2017), and newly reprocessed historical data using the latest software and GPS products. We include data from continuous GPS sites in Canada, the northern portions of the US, all of Greenland, and a set of globally distributed sites used to define the reference frame; and from repeated high accuracy campaign surveys in Canada. A new type of model is introduced for the vertical grid. It incorporates GPS observations with the crustal uplift predictions of Glacial Isostatic Adjustment (GIA) and elastic rebound models, which are especially important in areas with sparse coverage. Gridded uncertainty estimates are provided for each component of NAD83v70VG.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.004 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.009 | 0.003 |
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".