The effects of meltwater percolation on the seasonal isotopic signals in an Arctic snowpack
Bibliographic record
Abstract
Abstract We investigate the evolution of snow temperature, water content, density and stable water isotopes of δ18O at four Arctic snow-pit sites during early-season melt, in order to understand the effects of melt on snowpack stratigraphies and seasonal isotopic signals. We relate isotopic changes observed at these sites to temperature reconstructions derived from a 33 year firn-core record drilled on the same icefield. Decreases in seasonal isotopic amplitudes observed at all but one snow-pit site coincide with the percolation of more enriched meltwater into the snowpack, suggesting that meltwater percolation is the dominant process causing isotopic redistribution in Arctic snowpacks during the melt season. The decrease in isotopic range was accompanied by increases in mean δ18O values at all snow-pit sites. Positive degree-day (PDD) calculations are used to relate the amount of melt observed at the low-elevation snow-pit sites to the firn-core site. Results based on PDD values suggest an average overestimation of 1.1°C in average annual temperature reconstructions from the firn-core site from 1967 to 2006, with the possibility of errors in excess of 3°C during high-melt years.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| 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) | 0.000 | 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".