Impacts of Arctic precipitation changes on the downwelling limb of the Atlantic Meridional Overturning Circulation
Bibliographic record
Abstract
According to the latest IPCC report, under the RCP 8.5 scenario precipitation in the Arctic region may increase by as much as 50%. The projected 21stcentury decline of the Atlantic Meridional Overturning Circulation (AMOC) is attributed in part to this increase in precipitation and the associated river run-off. Here we analyze a set of 44-year long coupled climate model simulations in which only the precipitation between 70N and 90N is varied, to assess the impacts of the projected Arctic precipitation increase on deep ocean convection and the downward transport of dense waters that constitutes the downwelling limb of the AMOC. With a 50% increase in Arctic precipitation, mixed layer depths in the Nordic Seas and Labrador Seas reduce substantially, albeit with a longer response time in the latter. A 400% precipitation increase completely inhibits deep mixing. At the same time, the simulations display a 10%-50% reduction of the overturning strength, showing that a shutdown of convection does not automatically result in a shutdown of the AMOC. Theoretical studies have pointed out that, while dense water formation in the marginal seas is important for the density structure of the deep ocean, the downward volume transport associated with the AMOC is governed by oceanic conditions along the continental boundary of the North Atlantic Ocean (Iceland Basin, Irminger and Labrador Seas). In addition, the overflows along the Greenland-Scotland Ridge contribute to the AMOC. In the simulation for the present-day climate, the contributions of these two processes are of similar magnitude. The overflow transports are unaffected by a 50% increase in Arctic precipitation. In contrast, the sinking along the boundary of the North Atlantic Ocean reduces by roughly 60%. When the Arctic precipitation is increased by 400%, a clear decline in the overflows is simulated as well. In this study, we analyze the physical processes responsible for these changes in the downwelling transport.
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 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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".