Patterns of CO<sub>2</sub>and radiocarbon across high northern latitudes during International Polar Year 2008
Bibliographic record
Abstract
High-resolution in situ CO_2 measurements were conducted aboard the NASA DC-8 aircraft during the ARCTAS/POLARCAT field campaign, a component of the wider 2007–2008 International Polar Year activities. Data were recorded during large-scale surveys spanning the North American sub‐Arctic to the North Pole from 0.04 to 12 km altitude \nin spring and summer of 2008. Influences on the observed CO_2 concentrations were investigated using coincident CO, black carbon, CH_3CN, HCN, O_3, C_2Cl_4, and Δ^(14)CO_2 data, and the FLEXPART model. In spring, the CO_2 spatial distribution from 55°N to 90°N was largely determined by the long-range transport of air masses laden with Asian \nanthropogenic pollution intermingled with Eurasian fire emissions evidenced by the greater variability in the mid-to-upper troposphere. At the receptor site, the enhancement ratios of CO_2 to CO in pollution plumes ranged from 27 to 80 ppmv ppmv^(−1) with the highest anthropogenic content registered in plumes sampled poleward of 80°N. In summer, the CO_2 signal largely reflected emissions from lightning-ignited wildfires within the boreal forests of \nnorthern Saskatchewan juxtaposed with uptake by the terrestrial biosphere. Measurements within fresh fire plumes yielded CO_2 to CO emission ratios of 4 to 16 ppmv ppmv^(−1) and a mean CO_2 emission factor of 1698 ± 280 g kg^(−1) dry matter. From the ^(14)C in CO_2 content of 48 whole air samples, mean spring (46.6 ± 4.4‰) and summer (51.5 ± 5‰) Δ^(14)CO_2 values indicate a 5‰ seasonal difference. Although the northern midlatitudes were identified as the emissions source regions for the majority of the spring samples, depleted Δ^(14)CO_2 values were observed in <1% of the data set. Rather, ARCTAS Δ^(14)CO_2 observations (54%) revealed predominately a pattern of positive disequilibrium (1–7‰) with respect to background regardless of season owing to both heterotrophic respiration and fire-induced combustion of biomass. Anomalously enriched Δ^(14)CO_2 values (101–262‰) measured \nin emissions from Lake Athabasca and Eurasian fires speak to biomass burning as an increasingly important contributor to the mass excess in Δ^(14)CO_2 observations in a warming \nArctic, representing an additional source of uncertainty in the quantification of fossil fuel CO_2.
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 | 0.000 | 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".