The influence of an upper‐level frontal zone on the Mack Lake Wildfire environment
Bibliographic record
Abstract
Abstract Meteorological assessment of wildland fire danger has traditionally involved the identification of several synoptic weather types empirically determined to influence wildfire spread. Specifically, in the Great Lakes Region, high wildfire danger is often witnessed in association with northwesterly synoptic‐scale flow aloft. Such synoptic‐scale flow is regularly associated with the development of upper‐level frontal zones also known as upper‐level jet/front systems, which are often characterised by intrusions of stratospheric air into the troposphere. The notion that upper‐frontal development can play an important role in promoting wildfire spread is advanced through interrogation of the output from a fine‐scale numerical simulation of a documented explosive wildfire case; the Mack Lake Fire of May 1980. The Mack Lake case was characterised by a developing upper‐level front embedded within a shortwave trough in the vicinity of the fire location. The upper‐level front originated in northwesterly flow in central Canada as an upper‐tropospheric ridge amplified over western North America. A thermally indirect circulation at the jet exit region both contributed to the intensification of the front and was associated with a maximum in quasi‐geostrophic descent at mid‐levels upstream of the fire region. The subsidence ushered dry air from the middle and upper‐troposphere downward along sloping isentropes adiabatically warming and drying it along the way. A well‐developed dry air intrusion associated with the operation of these processes extended to nearly the 750 hPa level far downstream from the actual upper‐frontal zone supplying the fire environment with dry air that originated in the upper‐troposphere/lower stratosphere. The organised subsidence was also responsible for downward advection of high momentum air from within the frontal zone into the fire environment, further influencing the wildfire spread. We conclude that upper‐frontal processes, characteristic of northwesterly synoptic‐scale flow, are likely a contributing factor to the prevalence of wildfire spread under such synoptic‐scale conditions. Copyright © 2007 Royal Meteorological Society
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".