Regionale Atmosphärenmodellierung über dem nördlichen Nordatlantik : das Letzte Glaziale Maximum
Bibliographic record
Abstract
Regional atmospheric modelling results for the northern North Atlantic in the Last Glacial Maximum (LGM) are presented.The forcing global modelling followed in most aspects the Paleoclimate Modelling Intercomparison Project (PMIP) boundary conditions.The regional modelling almost reproduce the forcing data, considering the monthly background circulation, the monthly variability of circulation and the surface-near wind.In addition, the regional model's higher resolution lead to the following improvements upon the forcing data: in some cases precepitation over the Greenland-Iceland-Norway-Sea is more realistic; more detailed katabatic winds were modelled and in the February experiments they were stronger; partly orographic precipitation is stronger; no spectral artefacts in the precipitation occur off the Norwegian coast.Weak points of the regional modellings were found to be: too weak precipitation near the horizontal model boundary and over cold surface areas; in glacial August too extended snow covered areas in middle and western Europe, therefore too cold surface temperature in England; in glacial February too cold surface temperature in England, influenced by possibly too cold sea surface temperature on the near North Atlantic.The glacial August and February experiments were performed using the regional climate model REMO.The model area extends from the Pyrenees to the North Pole and from Labrador to the Kara Sea.The boundary condition used here mostly matches the PMIP suggestions.The only exception is the prescribed summer sea surface temperature on the northern North Atlantic, which follows the reconstruction by Weinelt et al. (1996) and is in parts more than 10 C warmer than the PMIP standard.The glacial results are contrasted with present-day regional modelling experiments and compared with the forcing global modelling data.In addition, the regional glacial results are compared with reconstructions from terrestrial proxy data, the present-day results with reanalysis data from the European Centre for Medium-range Weather Forecasts (ECMWF).The evaluation of the modelling results focuses on the monthly background circulation and the monthly variability of circulation, either at 500 hPa pressure level and near the surface, as well as on the climatic conditions at the surface.The monthly background circulation and the monthly variability of circulation in the regional experiments agree extensively with the forcing fields and are therefore assessed to be i Abstract successfully modelled.The moderate development of additional circulation variability compared to the forcing fields documents the model's independence to an appropriate extent.The higher abundance of circulation details in the individual modelling time-steps is found to some extent in the monthly background circulation and circulation variability, mainly next to prominent orographic structures.Differences in the monthly background circulation of the present-day experiments to the comparison data are reduced to known weak points of the forcing global model.The modelled present-day surface temperature is mostly compatible to the comparison data.Differences are caused by the above-mentioned weak points of the forcing modelling's background circulation.For the small part of the model area, where glacial temperature reconstructions after terrestrial proxy data are available, these in most cases match the modelled surface temperatures in August.Only in England do extensively modelled snow fields and therefore too cold temperatures contradict the reconstructions.Perhaps this could be corrected by longer spin-up times.In southern France and northern Spain the modelled glacial surface temperatures in February are compatible with the proxy-reconstructions.North of this, in western Europe, too cold modelled terrestrial temperatures are taken as an indication supporting the thesis, that on the North Atlantic the reconstruction by CLIMAP, the prescribed sea surface temperature is based on, cools down northwards too steeply and sees too extensive sea ice coverage.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.007 | 0.009 |
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; both teacher heads agree on what is shown here.
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".