A climatology of cold air outbreaks over North America: WACCM and ERA-40 comparison and analysis
Bibliographic record
Abstract
[1] A climatology of cold air outbreaks (CAOs) over North America is presented on the basis of a 50 year simulation of the Whole Atmosphere Community Climate Model (WACCM). This climatology is compared to a similar CAO climatology based on 45 years (1957–2002) of European Centre for Medium-Range Weather Forecasts 40 Year Re-Analysis Project (ERA-40) data. A CAO is identified at a given grid point if the following criteria are met: (1) the surface temperature is lower than 1.5 standard deviations below the 31 day climatological running mean, (2) the standard deviation in temperature is greater than 2 K, and (3) conditions 1 and 2 are satisfied over a contiguous area of ∼5° longitude by 5° latitude. WACCM and ERA-40 comparisons are shown for CAO frequency, temperature anomaly from 31 day climatological mean, geographical location, minimum temperature, and areal extent. Overall, CAOs in WACCM occur ∼30% less frequently than in ERA-40 but cover ∼30% greater area and are 1–2 K lower. In midwinter, WACCM CAOs form at lower latitudes and penetrate to lower latitudes compared to CAOs in ERA-40.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".