Searching for Global Dimming Evidence at SGP and Update of ARM Submissions to BSRN
Bibliographic record
Abstract
Global dimming, usually defined as a reduction of incoming solar radiation (insolation) at the surface of the earth, is a topic being discussed with increasing frequency. A recent news article on global dimming in the web-based newspaper the Guardian Unlimited seems to have brought this issue to the forefront with scientists and laypeople alike. In fact, there is a special session devoted to global dimming at the upcoming May 17-21 American Geophysical Union (AGU) meeting in Montreal, Canada. The article quotes Atsumu Ohmura and references his findings on this subject. Ohmura has found evidence that at some locations insolation has been reduced by 10% over a period of 30 years (60’s to the 80’s). Another scientist, Helen Power, quoted in the same Guardian Unlimited article has found that in the 1990’s insolation on average has increased slightly in Germany when compared to prior decades, indicating that for at least the area of study global dimming may be easing (Power 2003). Graham Farquhar is another researcher who has been studying global dimming. His work on the subject has reconciled a paradox in evaporation pan studies; i.e., evaporation has been decreasing with increasing global temperatures (Roderick 2002). Beate Liepert, who is heading the special session at the upcoming AGU meeting, studied surface solar radiation at sites in the United States from 1961 to 1990 (Liepert 2002). He found that insolation declined almost 20 W/m over the thirty years examined in his work. After examining thermopile pyranometer data over the past fifty years, Gerald Stanhill concludes that the globally averaged reduction of insolation has averaged 0.51 ±0.05 W/m per year (Stanhill 2001). In the current work data collected at the Southern Great Plains (SGP) facility are analyzed in an effort to determine if evidence of global dimming (or brightening) can be discerned. The dataset begins in 1993 and continues through 2003, providing just over one decade of data for examination. While most of the previous studies have focused solely on global radiation, global, diffuse, and direct shortwave parameters are investigated here.
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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 | 0.027 | 0.101 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.013 | 0.011 |
| Science and technology studies | 0.004 | 0.002 |
| Scholarly communication | 0.009 | 0.004 |
| Open science | 0.003 | 0.008 |
| Research integrity | 0.004 | 0.004 |
| Insufficient payload (model declined to judge) | 0.130 | 0.057 |
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".