Year‐round observations of the energy and water vapour fluxes above a boreal black spruce forest
Bibliographic record
Abstract
Abstract Fluxes of energy and water vapour were measured continuously over an ∼120‐year‐old black spruce (Picea mariana (Mill.) B.S.P.) forest in northern Saskatchewan, Canada, from 6 May 1999 to 5 May 2001 using the eddy covariance technique as part of the Boreal Ecosystem Research and Monitoring Sites (BERMS) program. These results demonstrate that long‐term eddy covariance fluxes can reliably be measured during the harsh boreal winter. Typical daytime bulk surface conductance values were about 5–8 mm s−1 during the growing season. Surface conductance sharply declined after midday in response to increasing vapour pressure deficit. The monthly mean values of energy balance components showed that, in spring (March–June), partitioning of available energy flux was mainly in the form of sensible heat, which changed to almost equal proportions of sensible and latent heat in the summer (July–October). In winter (November–February), most of the net radiation was balanced by sensible heat flux. The monthly mean values of net radiation, sensible heat and latent heat flux were about −20 to 20 W m−2, −10 to 25 W m−2 and 5 to 10 W m−2 respectively in winter. The average mid‐day Bowen ratios were approximately 3·5, 1·7 and 5·2 in the spring, summer and winter seasons respectively. The maximum daily evaporation was about 3·5 mm day−1 in summer and 0·1–0·25 mm day−1 in winter. Over the 2 year period, the accumulated precipitation was 835 mm; this compared with 711 ± 70 mm of evapotranspiration, which showed that more than 85% of water was returned to the atmosphere through evapotranspiration. This study reports the first complete annual cycles of energy and water vapour fluxes at this black spruce site. Since black spruce is the dominant tree species in the North American boreal forest, these results have significance for regional and global energy and water cycles. Copyright © 2003 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
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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".