Thermobaric Processes Both Drive and Constrain Seasonal Ventilation in Deep Great Slave Lake, Canada
Bibliographic record
Abstract
Abstract The contrasting roles of seasonal stratification and seasonal ventilation are among the most important attributes of lake systems in defining their geochemistry, biology and response to climate forcing. The physical processes that regulate these processes are especially significant in very deep lakes, where the joint effect of temperature and pressure on water density becomes important. Here we report on a year‐long time series (2019–2020) of temperature from a mooring deployed in seasonally ice covered and dimictic Great Slave Lake (614 m depth). Because the temperature of maximum density (T MD ) decreases with increasing pressure, once ∼4°C water begins to sink, it is no longer at its depth‐specific maximum density and additional processes are required to drive convection and convective mixing. The key physical mechanism governing deep‐water renewal is the conditional thermobaric instability. We show here that (a) different temperature dynamics control the quantity and timing of convective renewal in the upper ∼200 m versus deep‐water renewal below; (b) fall and spring deep‐water renewal events are asymmetric and linked to weather during the brief time of ice forming (melting) and surface temperatures cooling (warming) through 4°C; (c) short term variability (days to weeks) related to the length of time between surface waters passing through T MD and ice formation (fall) and melt (spring) shapes the subsequent thermal structure; and (d) the penetration of solar radiation through ice in early spring drives penetrative convection in the upper layer, deepening the mixed‐layer, and this likely affects the timing of spring phytoplankton production.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".