Transport and deposition of radionuclides after the Fukushima nuclear accident: international model inter-comparison in the framework of a WMO Task Team
Bibliographic record
Abstract
In the framework of a Task Team set up after the Fukushima accident sponsored by WMO, the atmospheric transport\nand deposition models (ATDMs) FLEXPART (Austria), HYSPLIT (U.S.), MLDP0 (Canada), NAME (UK)\nand RATM (Japan) were inter-compared. These models are well-known and widely used for emergency response\nactivities. As alternative model input data, JMA made available a Meso-Analysis with 5 km/ 3 hour resolution, and\na radar/rain gauge precipitation analysis with 1 km and 30 minutes resolution. To allow maximum flexibility regarding\nthe release rates of key nuclides, the computations were based on the concept of source-receptor matrices,\nin this connection also called transfer coefficient matrices (TCM). The matrices are calculated every 3 hours after\n11 March 2011 00 UTC, based on unit emissions, and thus can be overlaid with any present and future release\nscenario that becomes established. As computational species, the model considered tracers, depositing gases and\ndepositing aerosols, allowing accounting for the range of substances emitted during a nuclear accident. The model\ncomparison was based on observed deposition patterns of Cesium-137 in the Fukushima province as collected by\nMEXT/USDOE shortly after the accident, and a few available in situ stations measuring radioactive isotopes. To\nperform a statistical comparison, established parameters like correlation coefficient (r), fractional bias (FB) and\nfigure of merit in space (FMS) were used. A further ensemble analysis was performed to determine what subset\nof model results out of all available would provide non-redundant information and thus is optimal to describe the\ntransport and deposition during the accident. The investigation showed (i) that a TCM-based calculation approach\nhas a lot of merits due to its flexibility, (ii) that models tended to perform better if they were run in improved resolution\nor directly with the Japanese Meso-analysis, (iii) that the model results depend on the selection of the source\nterm with the term provided by JAAE ranking best in terms of reproducing local deposition patterns, and (iv) that\nthe ensemble analysis is a very useful approach to select optimized subsets of models in case that measurement\ndata are already available.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".