Evidence for recent changes in a surface‐air warming singularity in late winter over central North America
Bibliographic record
Abstract
Evidence for an earlier onset of spring in recent years is supported by daily temperature data from central North America. From 1976–1999, mean temperatures during February 15th through 24th were appreciably higher (5°C or more over large areas) than during 1952–1975. This is associated with a strengthened Aleutian Low for those calendar days during 1976–1999, with negative pressure anomalies extending well into North America. This apparently reflects a decrease in strong, cold, high‐pressure systems moving from western Canada into the north central United States during late February. These changes appear to be related to conditions in and over the North Pacific Ocean, possibly in conjunction with global warming, although the latter signal is not clearly obvious. Comparison of time series of daily minimum temperatures for the earlier period (1952–1975) and the recent period (1976–1999) indicates other times of the year when an appreciable warming has occurred; such warming is largely confined to the first half of the calendar year.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".