Inverse Modeling of the Net Water Balance of the Black Sea From the Last Glacial Maximum to the Present
Bibliographic record
Abstract
Abstract The net freshwater balance plays a central role in the biological, chemical, geological and physical changes in the Black Sea since the Late Glacial Maximum (LGM), that is, 18–24,000 years BP. Past estimates of this balance vary widely. Here we solve inversely a water balance model coupled to two previously published Bosporus flow models, that is, flow rates controlled either by hydraulics with a critical height or by channel friction. We drive both models with two previously proposed Black Sea water‐level histories, that is, a smooth transition to saltwater entry and the “flood” scenario. First, we find that flow control by channel friction is far more likely than control by critical‐height hydraulics, as the latter does not allow Marmara Sea water to enter the Bosporus at any time in the past and predicts present‐day outflows that are far greater than observed. Prior to intense glacial melting (12–14,000 years BP), all models retrodict net freshwater inflow far less than previously assumed, that is, on the order of −1 to +10 km 3 yr −1 , rather than +100 s km 3 yr −1 . Thus, our results explain the ease by which the Black Sea could switch from evaporative to water gain conditions, as implied by water‐level records for that period. In addition, the channel friction model hindcasts glacial meltwater spikes during the transition from the LGM to the Holocene that are much smaller, that is, 100–250 km 3 yr −1 , than retrodicted by the hydraulic model or reported in the literature, that is, >1,000 km 3 yr −1 .
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| 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".