The Missing "Missing Sink"
Bibliographic record
Abstract
To assess CO2 fluxes of the terrestrial biosphere, ground-based inventories, flux measurements and bottom-up modeling approaches are used. In most cases inventory-based approaches are not able to produce a full carbon account (FCA). The FCA refers to a carbon budget that is complete, encompasses all components, and is applied continuously in time. Atmospheric inversion modeling implicitly measures the sum of all fluxes, meaning a FCA. Eddy-covariance measurements have huge variations and are difficult to scale up to regional and decadal levels. Bookkeeping up to more complex process-based models rely on land-use change estimates over time, which have large uncertainties. To overcome the accounting gap between top-down and bottom-up measurements, the IPCC introduced the terrestrial "missing sink" concept by taking long-term land-use changes into account to further break down the global carbon budget. IIASA has developed a bottom-up FCA approach that breaks down the terrestrial carbon balance of Russia for 1990 (1988–1992) resulting in a sink. This was then combined with the terrestrial sink strength of the extra-tropical Northern Hemisphere (approximately > 30°N) determined via top-down atmospheric inversion. Using this approach, the remainder, the terrestrial sink strength of the extra-tropical Northern Hemisphere without Russia, could then be determined with a relative uncertainty that is smaller (i.e., < 100%) than the uncertainties exhibited by inverse models. From the analysis it can be concluded that the "missing sink" issue can be reduced to an issue of relevant accounting due to the fact that the combined top-down/bottom-up approach does not identify any missing sink. Key words: carbon balance, flux, missing sink, inverse modeling, inventory approaches, full carbon accounting, top-down/bottom-up approaches, terrestrial ecosystems, Russia
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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 | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.008 |
| Open science | 0.001 | 0.003 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".