Evolution of incipient lowland thermokarst features in the Blackstone River Valley, Yukon
Bibliographic record
Abstract
Roy-Leveillee, P (2017) Evolution of incipient lowland thermokarst features in the Blackstone River Valley, Yukon. In 45th Annual Yellowknife Geoscience Forum Abstracts; Northwest Territories Geological Survey, Yellowknife, NT., Compiled by Irwin, D., Gervais, S.D., and Terlaky, V. YKGSF Abstracts Volume 2017. Abstract:Widespread thermokarst initiation and the acceleration of thermokarst development in permafrost peatlands can result in ecological change, threaten the cultural integrity of northern indigenous people, change rates of carbon storage and release at high latitudes, and affect the geomorphology of Arctic and subarctic landscapes. Despite the multilayered significance of intensified thermokarst activity the processes controlling the early stages of thermokarst development and the factors differentiating features that will stabilize from those that will continue to expand are still poorly understood. Here we present preliminary observations of conditions associated with the stabilization or expansion of incipient thermokarst ponds in the Blackstone River valley, central Yukon. In this large valley located near the limit between continuous and discontinuous permafrost, the alluvial deposits of the river bed are surrounded with extensive moraines and outwash deposits. The vegetation cover is dominated by tundra, and ice wedge polygon networks are extensive. Signs of ice wedge degradation are widespread in several parts of the valley. However, comparison of recent remotely sensed imagery with historical aerial photographs indicates that several degradation features have been stable for at least 20 years, while others have expanded rapidly. This stabilization is associated with vegetation growth in the thaw features, causing partial terrestrialization of incipient ponds and cooling of the ground beneath. Mean annual temperatures near the ground surface beneath small ponds with dense Carex spp. or aquatic mosses ranged from - 1.5 to -2.7°C, whereas such temperatures ranged from 0.3 to 2.9°C beneath similarly shallow but unvegetated or sparsely vegetated water in expanding ponds. Expanding ponds exhibiting signs of aggressive shore erosion were often connected to thermo-erosion gullies, which visibly contributed to destabilising the shore bank. Such association with thermo-erosion gullies also enabled rapid degradation along some banks of seasonal ponds, preventing the stabilization that could result from prolonged loss of contact between the bank foot and water every summer.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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".