Subpolar Atlantic Meridional Overturning in Community Earth System Model (CESM): setting up the further experiment
Bibliographic record
Abstract
The Atlantic Meridional Overturning Circulation (AMOC) is a three-dimensional system of ocean currents contributing to a relatively mild climate in northern Europe. AMOC transports vary on a range of time scales, from centennial to daily. Despite a wide history of research on AMOC variability from both measurements and modeling perspectives, the role of atmospheric noise in subseasonal and intra-annual AMOC variations remains unclear. In the current study, we describe the modeling experiment planned to reveal the importance of mesoscale winds around the southern tip of Greenland, named Tip Jets, in AMOC variability. Tip Jet wind events have no regularity in frequency and intensity, they mostly depend on the Icelandic Low location and are partly associated with a positive NAO phase in winter. The experiment design is based on implying the perturbations in the momentum, heat, and freshwater forcing associated with Tip Jet events. Therefore, we constructed the composite Tip Jet forcing using daily ERA5 (25 km, December-March, 1969-2019) wind, surface fluxes, and precipitation/evaporation rates. These composite fields of anomalies are planned to be added to the CESM-derived climatology to describe the possible response of the AMOC system to these types of noise forcing. Setting up the experiment included the model verification based on the comparison between the monthly output from the ~0.1 ° CESM Parallel Ocean Product (POP) simulations and the observational OSNAP array that combines measurements along the line between Labrador, Greenland, and the European shelf. The mean state of the atmosphere from CESM (50 km, monthly) was compared to the ERA5 (25 km, monthly). Generally, the CESM model reproduces the AMOC at OSNAP well. In conclusion, this preliminary research shows that AMOC is well simulated by the Community Earth System Model in the Subpolar North Atlantic. Also, the current research proposes patterns of noise forcing over the North Atlantic Subpolar Gyre that will be used in further modeling experiments.
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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 | 0.003 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".