Integration of CO<sub>2</sub> flux and remotely‐sensed data for primary production and ecosystem respiration analyses in the Northern Great Plains: potential for quantitative spatial extrapolation
Bibliographic record
Abstract
ABSTRACT Aim Extrapolation of tower CO2 fluxes will be greatly facilitated if robust relationships between flux components and remotely sensed factors are established. Long‐term measurements at five Northern Great Plains locations were used to obtain relationships between CO2 fluxes and photosynthetically active radiation (Q), other on‐site factors, and Normalized Difference Vegetation Index (NDVI) from the SPOT VEGETATION data set. Location CO2 flux data from the following stations and years were analysed: Lethbridge, Alberta 1998–2001; Fort Peck, MT 2000, 2002; Miles City, MT 2000–01; Mandan, ND 1999–2001; and Cheyenne, WY 1997–98. Results Analyses based on light‐response functions allowed partitioning net CO2 flux (F) into gross primary productivity (Pg) and ecosystem respiration (Re). Weekly averages of daytime respiration, γday, estimated from light responses were closely correlated with weekly averages of measured night‐time respiration, γnight (R2 0.64 to 0.95). Daytime respiration tended to be higher than night‐time respiration, and regressions of γday on γnight for all sites were different from 1 : 1 relationships. Over 13 site‐years, gross primary production varied from 459 to 2491 g CO2 m−2 year−1, ecosystem respiration from 996 to 1881 g CO2 m−2 year−1, and net ecosystem exchange from −537 (source) to +610 g CO2 m−2 year−1 (sink). Maximum daily ecological light‐use efficiencies, ɛd,max = Pg/Q, were in the range 0.014 to 0.032 mol CO2 (mol incident quanta)−1. Main conclusions Ten‐day average Pg was significantly more highly correlated with NDVI than 10‐day average daytime flux, Pd (R2 = 0.46 to 0.77 for Pg‐NDVI and 0.05 to 0.58 for Pd‐NDVI relationships). Ten‐day average Re was also positively correlated with NDVI, with R2 values from 0.57 to 0.77. Patterns of the relationships of Pg and Re with NDVI and other factors indicate possibilities for establishing multivariate functions allowing scaling‐up local fluxes to larger areas using GIS data, temporal NDVI, and other factors.
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".