Sea ice freeboard in McMurdo Sound, Antarctica, derived by surface-validated ICESat laser altimeter data
Bibliographic record
Abstract
[1] Previous investigations have linked changes in the multiyear sea ice area of McMurdo Sound, Antarctica, from 1213 km2 in 2003 to 4923 km2 in 2005, to the passage of large tabular icebergs preventing the annual sea ice breakout. This maximum coverage then gradually diminished, by 2009 covering 1453 km2. This investigation employs the use of the Ice, Cloud, and land Elevation Satellite (ICESat) laser altimeter to derive freeboard of sea ice in McMurdo Sound from 2003 to 2009 and hence infer thickness changes over this time period. Two techniques for freeboard retrieval are compared. Method-1 (M-1) follows those previously presented in the literature using the lowest elevations to construct an estimate of sea surface height. However, the lack of leads in the study area motivated the development of Method-2 (M-2) which utilizes tide models. Each year is divided into two investigation periods from September to December and February to June, and these investigations were further segmented by sea ice type, first-year (FY), and multiyear (MY). Both applied methods reveal a statistically significant linear increase in multiyear sea ice freeboard. For M-1, the mean freeboard increased over the study period from 0.53 to 1.00 m and for M-2 from 0.46 to 0.95 m. Evidence is presented that the multiyear sea ice freeboard increase is strongly linked to the development and incorporation of a subice platelet layer. No statistically significant trends were observed for first-year sea ice. ICESat derived freeboards over first-year and multiyear sea ice areas compare within one standard deviation of airborne measured freeboard in November 2009.
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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 | 0.002 | 0.001 |
| 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 | 0.002 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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; both teacher heads agree on what is shown here.
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".