Persistence and Variability of Ice Stream Grounding Lines on Retrograde Bed Slopes
Bibliographic record
Abstract
Abstract. In many ice streams, basal resistance varies in space and time due to the dynamically-evolving properties of subglacial till. These variations can cause internally-generated oscillations in ice stream flow. However, the potential for such variations in basal properties are not considered by conventional theories of grounding line stability on retrograde bed slopes, which assume that bed properties are static in time. Using a numerical flowline model, we show how internally-generated, transient variations in ice stream state interact with retrograde bed slopes. In contrast to predictions from the theory of the marine ice sheet instability, our simulated grounding line is able to persist and reverse direction of migration on a retrograde bed when undergoing oscillations in the grounding line position. In turn, the presence of a retrograde bed may also suppress or reduce the amplitude of internal oscillations in ice stream state. We explore the physical mechanisms responsible for these behaviors and discuss the implications for observed grounding line migration in West Antarctica.
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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 | 0.000 | 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".