Canadian Arctic Permafrost Observatories: Detecting contemporary climate change through inversion of subsurface temperature time series
Bibliographic record
Abstract
We describe long‐term permafrost temperature and climate change observatories established in the northeastern Canadian High Arctic (77°–82.5°N). Two sites have deep temperature logs (165 and 800 m), and thermistor cables and automatic loggers have been installed in the upper ∼65 m. The third site has multiple temperature logs at three 61‐m boreholes with thermistor cables frozen into the permafrost. A fourth deep site (750 m) is included for regional completeness. Geothermal spectrum inversion is used to determine ground surface temperature histories. The Little Ice Age is resolved from the mid‐1700s to mid‐1800s with surface temperatures ∼ 1 K below the long‐term mean; a subsequent recovery yields late 20th century surface temperatures ∼3 K higher. These results correlate with similar reconstructions reported for Greenland ice cap holes GRIP and Dye‐3 to the southeast. The Canadian and Greenland surface temperatures show a weak, inverse correlation with the North Atlantic Oscillation, suggesting recent climate change as a common causal source. Simultaneous inversions of multiple logs over 22 years at the 61‐m holes resolve two to three major cycles in ground surface temperature variation over the latter half of the 20th century. Here permafrost ground temperatures increase 0.3°–0.5°C/decade, compared to 0.6°C/decade for air temperatures; annual total snow increases 22 cm/decade and may insulate permafrost from the larger transient trends in air temperatures. Finally, atmospheric temperature inversions prevalent in Arctic winters may contribute to anomalously high ground surface temperatures observed at two locations.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 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".