Changes in soil temperature and active layer thickness during the twentieth century in a region in western Canada
Bibliographic record
Abstract
Increases in active layer thickness and permafrost degradation induced by climate warming may have profound socio‐economic and eco‐environmental consequences. Using a process‐based model of Northern Ecosystem Soil Temperature (NEST) and data from climate records, remote sensing vegetation parameters, and soil features, we simulated soil temperature and active layer thickness (ALT) for a region in western Canada during the twentieth century. The results showed that the region‐averaged annual mean soil temperatures at different depths responded to air temperature forcing consistently during the twentieth century, but with reduced magnitudes in both long‐term trend and interannual variation. From the 1900s to 1986–1995, ALT increased 124 cm (or 79%) in the isolated and sporadic discontinuous permafrost zones, 59 cm (or 37%) in the extensive discontinuous permafrost zone, and 20 cm (or 21%) in the continuous permafrost zone on the basis of the current permafrost distribution map. The simulated results also indicated the disappearance of 17% of the permafrost in the discontinuous permafrost zone from the 1900s to the 1940s, and another 22% from the 1940s to 1986–1995. General agreement was found when comparing the simulated results with soil temperature records at climate stations, ALT at survey sites, and rates of permafrost degradation interpreted from aerial photographs. Owing to differences in spatial scales, spatial coverage, and time periods, many of the comparisons were not strict 1‐to‐1 comparisons and should instead be viewed as indirect supporting evidence.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".