Centennial scale climate oscillations from southern Siberia in the Last Glacial Maximum
Bibliographic record
Abstract
A lack of adequate high resolution climate proxy records for the Last Glacial Maximum (LGM) has prevented the extrapolation of climate–solar linkages on centennial time scales prior of the Holocene. Therefore, it is still unknown whether centennial climate variations of the last ten thousand years convey a universal climate change or merely represent a characteristic of the Holocene. Recently published high resolution climate proxy records for the LGM allowed us to extrapolate climate–solar linkages on centennial time scales ahead of the Holocene. Here we present the analysis of a high resolution pollen concentration record from Lake Kotokel in southern Siberia, Russia, during the LGM. The record reflects the dynamics of vegetation zones and temperature change with a resolution of ~ 40 years in the continental climate of north-eastern Asia. We demonstrate that our pollen concentration record, the oxygen isotope δ18O record from the Greenland ice core project NGRIP (NorthGRIP), the dust-fall contributions in Lake Qinghai, China, grain size in the Gulang and Jingyuan loess deposits, China, and the composite oxygen isotope δ18O record from the Alpine cave system 7H reveal cooler to warmer climate fluctuations between ~ 20.6 and 26 ka. Such fluctuations correspond to the ~ 1000-yr, 500-600-yr and 210-250-yr cycles possibly linked to the solar activity variations and recognized in high resolution Holocene proxies all over the world. We further show that climate fluctuations in the LGM and Holocene are spectrally similar suggesting that linkages between climate proxies and solar activity at the centennial time scale in the Holocene can be extended to the LGM.
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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 | 0.001 | 0.002 |
| 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".