Time‐series of zenith radiance and surface flux under cloudy skies: Radiative smoothing, optical thickness retrievals and large‐scale stationarity
Bibliographic record
Abstract
Cloudy sky zenith radiance time‐series covering spatial scales a few meters up to 200–400 km measured by a ground‐based photometer at 753 nm are investigated with 2nd‐order structure functions, and compared to broad‐band short‐wave column transmittance. A previously reported scale break occurs at scales on the order of the vertical cloud extension due to radiative smoothing (i.e., lateral photon transport by diffusion in optically thick clouds). We use simulated radiance and flux fields for 3D clouds to explain why optical depths can be extracted with reasonable accuracy from surface fluxes by using 1D radiative transfer theory at large‐enough scales. We also show clear evidence of a transition from nonstationary to stationary behavior, i.e., a scale break, occurring at spatial scales of a few tens of kilometers. We argue that this qualitative change in the correlations of remotely observed radiation fields is likely to carry over to the most highly variable inherent cloud property, namely optical depth.
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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 | 0.002 |
| 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 | 0.000 | 0.001 |
| 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".