UV (280 to 400 nm) optical properties in a Norwegian fjord system and an intercomparison of underwater radiometers
Bibliographic record
Abstract
The depth to which solar ultraviolet (UV) radiation penetrates water columns is highly variable.The range in diffuse attenuation coefficients observed in the clearest ocean waters versus small oligotrophic lakes can be as much as 3 orders of magnitude.In this study, we investigated the variability of UV penetration (and its sources) in a typical Norwegian fjord system (Samnanger fjord, 60° N, 5° E) after the main spring diatom bloom had passed, so that the primary production in the fjord was low, with chl a concentrations of 1 to 2 mg m -3 at 10 m depth (April 1999).At 320 nm, diffuse attenuation coefficients varied between 1.2 and 5.0 m -1 from the outer to the inner part of the fjord.At 305 nm, the variation was between 2.3 and 5.4 m -1 .Less variability was found at longer wavelengths (340 and 380 nm).River run off, containing high concentrations of colored dissolved organic matter (CDOM), provided a low salinity layer of highly UV-absorbing water at the surface.There was a strong correlation between diffuse attenuation coefficients in the UV and CDOM, but only a weak correlation with chl a. Uncertainty in measuring diffuse attenuation coefficients are seldom addressed.Thus, we undertook an intercomparison of diffuse attenuation coefficients calculated from data produced using 3 different UV radiometers: a spectroradiometer, a narrowband filter radiometer and 2 moderate-bandwidth filter radiometers.The deviations in attenuation ranged from 20 to 40%, being most pronounced at the shortest wavelengths (305 and 320 nm) at 3 different stations.This intercomparison illustrates that there has not been significant improvement in the uncertainties of measuring diffuse attenuation coefficients since a similar intercomparison was performed in 1994.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".