Early Holocene Laurentide Ice Sheet retreat influenced summer atmospheric circulation in the North American Arctic: Evidence from precipitation isotope and temperature proxy records and a climate model
Bibliographic record
Abstract
Changes in ice sheet size and configuration impact global moisture and heat transport, but few proxy records examine these impacts. High-latitude precipitation-isotope proxy records are often interpreted to reflect temperature change, but can also reflect changes in moisture source. We present independent sub-centennial-scale records of summer temperature and summer precipitation δ2H from the same lake sediment archive on northeastern Baffin Island. We also examine published TraCE-21k transient model simulation results. These records span from 12 to 7 ka, when the Laurentide Ice Sheet underwent major retreat. The correlation structure between summer temperature and precipitation δ2H on northeastern Baffin Island changed from negative to positive around 10 ka. We interpret this change in correlation structure to indicate a shift in moisture sources to northeastern Baffin Island. TraCE-21k results suggest that moisture sources in this region are controlled by the relative strength of the high pressure systems and associated anticyclonic circulation over the Greenland and Laurentide ice sheets. We therefore interpret the proxy records as follows: when the Laurentide high dominated prior to 10 ka, northerly winds brought cold, dry Arctic air to the region, allowing 2H-enriched local sea breezes to provide most of the moisture to Baffin Island. After 10 ka, the Greenland high dominated, causing southerly flow to carry warm, moist, 2H-depleted air masses to northeastern Baffin Island. Regional centennial-scale cooling events caused by periodic freshwater inputs to the Labrador Sea throughout the Early Holocene were also associated with intervals of 2H-enriched summer precipitation. This study provides evidence that atmospheric circulation was influenced by the waning continental ice sheets. Similar ice-sheet influences are critical to consider when interpreting precipitation isotope proxy records spanning periods of dramatic ice-sheet change. These results demonstrate that precipitation isotopes can reflect changes in atmospheric circulation in the geologic record.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".