Seasonal evaluation of tropospheric CO <sub>2</sub> over the Asia-Pacific region observed by the CONTRAIL commercial airliner measurements
Bibliographic record
Abstract
Measurement of atmospheric carbon dioxide (CO 2 ) is indispensable for top-down estimation of surface CO 2 sources/sinks by an atmospheric transport model. Despite the growing importance of Asia in the global carbon budget, the region has only been sparsely monitored for atmospheric CO 2 and our understanding of atmospheric CO 2 variations in the region (and thereby that of the regional carbon budget) is still limited. In this study, we present climatological CO 2 distributions over the Asia-Pacific region obtained from the CONTRAIL (Comprehensive Observation Network for TRace gases by AIrLiner) measurements. The high-frequency in-flight CO 2 measurements over 10 years reveal a clear seasonal variation in CO 2 in the upper troposphere (UT), with a maximum occurring in April–May and a minimum in August–September. The CO 2 mole fraction in the UT north of 40 ∘ N is low and highly variable in June–August due to the arrival of air parcels with seasonally low CO 2 caused by the summertime biospheric uptake in boreal Eurasia. For August–September in particular, the UT CO 2 is noticeably low within the Asian summer monsoon anticyclone associated with the convective transport of strong biospheric CO 2 uptake signal over South Asia. During September as the anticyclone decays, a spreading of this low-CO 2 area in the UT is observed in the vertical profiles of CO 2 over the Pacific Rim of continental East Asia. Simulation results identify the influence of anthropogenic and biospheric CO 2 fluxes in the seasonal evolution of the spatial CO 2 distribution over the Asia-Pacific region. It is inferred that a substantial contribution to the UT CO 2 over the northwestern Pacific comes from continental East Asian emissions in spring; but in the summer monsoon season, the prominent air mass origin switches to South Asia and/or Southeast Asia with a distinct imprint of the biospheric CO 2 uptake. The CONTRAIL CO 2 data provide useful constraints to model estimates of surface fluxes and to the evaluation of the satellite observations, in particular for the Asia-Pacific region.
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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 | 0.000 | 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 | 0.000 |
| 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 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".