Assessing the trends and effects of environmental parameters on the behavior of mercury in the lower atmosphere over cropped land over four seasons
Bibliographic record
Abstract
Abstract. Mercury is released to the atmosphere from natural and anthropogenic sources. Due to its persistence in the atmosphere, mercury is subject to long range transport and is thus a pollutant of global concern. The terrestrial ecosystem is an important atmospheric mercury sink as a significant portion of the mercury emitted can be accumulated on soil surfaces making terrestrial surfaces an important source of previously emitted and deposited mercury. Studying the factors and processes that influence the behavior of mercury from terrestrial sources is thus important for a better understanding of the role of natural ecosystems in the mercury cycling and emission budget. A one year study (July 2006–August 2007) was conducted at Elora, Ontario, Canada to measure total gaseous mercury (TGM), reactive gaseous mercury (RGM) and particulate bound mercury (HgP) as well as TGM fluxes over different ground cover spanning the four seasons typical of a temperate climate zone. TGM concentrations were measured using a mercury vapour analyzer (Tekran 2537A) while RGM and HgP were measured with the Tekran 1130/1135 speciation unit coupled to another mercury vapour analyzer. A micrometeorological approach was used for TGM flux determination using a continuous two-level sampling system for TGM concentration gradient measurement above the soil surface and crop canopy. The turbulent transfer coefficients were derived from meteorological parameters measured on site. A net TGM volatilization (6.31±33.98 ng m−2 h−1, annual average) to the atmosphere was observed during the study. Average TGM concentrations and TGM fluxes showed significant seasonal differences and distinct diurnal patterns while no trends were observed for HgP or RGM. Highest TGM concentrations recorded in late spring and fall were due to meteorological changes such as increases in net radiation and air temperature in spring and lower atmospheric mixing height in fall. Highest TGM fluxes (18.1 ng m−2 h−1, monthly average) were recorded in late spring but also during specific events in winter and fall. The main factors influencing TGM flux were soil moisture content, soil temperature, precipitation events and ground cover. These trends indicate that the soil surface could be a significant mercury source in spring and summer seasons but also under specific meteorological conditions in winter or fall.
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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 | 0.001 |
| 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".