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Record W2654162703 · doi:10.5287/ora-mvgpra92d

The dynamics of a changing arctic ocean

2015· dissertation· en· W2654162703 on OpenAlexaboutno aff
Peter E. D. Davis

Bibliographic record

VenueOxford University Research Archive (ORA) (University of Oxford) · 2015
Typedissertation
Languageen
FieldEarth and Planetary Sciences
TopicArctic and Antarctic ice dynamics
Canadian institutionsnot available
FundersNatural Environment Research Council
KeywordsHaloclineSea iceArctic sea ice declineArctic ice packOceanographyArcticOcean gyreDrift iceThermohaline circulationArctic geoengineeringClimatologyEkman transportGeologySea ice thicknessArctic dipole anomalyAntarctic sea iceEnvironmental scienceOcean currentSalinity

Abstract

fetched live from OpenAlex

The Arctic Ocean is undergoing a period of rapid transition, and many different aspects of its environment (ocean, sea ice, and atmosphere) are changing faster than has ever previously been observed. Motivated by the role that the Arctic plays in the global climate and ocean circulation, the aim of this thesis is to investigate how the changing environment is affecting the dynamics and circulation of the Arctic Ocean. Observations show that freshwater accumulation in the Beaufort Gyre of the western Arctic Ocean has accelerated over the past decade. First, a simple process model and idealised perturbations to the annual cycle in ocean surface stress are used to show that the decline in Arctic sea ice cover and an increase in the annual mean momentum flux can explain this accelerated accumulation. The adjustment timescale and quantity of freshwater accumulated are determined by a balance between Ekman pumping and an eddy-induced volume flux, highlighting the importance of eddies in the changing Arctic. Sea ice decline may also drive periodic increases in vertical mixing. Using a 1D model of the Arctic Ocean water column, the competing effects of elevated vertical mixing and enhanced freshwater input on the stratification, the stability of the cold halocline, and the sea ice cover at the surface are explored. An elevated diffusive heat flux driven by stronger vertical mixing has little effect on the sea ice. Instead, the erosion of the cold halocline, which isolates the sea ice from the warm Atlantic water, represents the most important feedback for ongoing sea ice melt. The changing Arctic Ocean will further affect the freshwater export to either side of Greenland; however, local dynamics will also be important. In this chapter, the vertical structure of the tides in Nares Strait in the Canadian Arctic Archipelago are explored, as tidal turbulence may represent an important frictional constraint for the freshwater flow in this region. The tides propagate as either standing or progressive waves, and the vertical structure is set by the proximity of the semi-diurnal critical latitude, the requirement of no normal flow through the coast, and the strong stratification at the surface. There is little temporal variability in the vertical structure, and tidal dissipation is comparable in magnitude to that over the highly dissipative region of the northwest European Shelf.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.038
Threshold uncertainty score0.076

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0010.001
Scholarly communication0.0020.001
Open science0.0000.001
Research integrity0.0010.000
Insufficient payload (model declined to judge)0.0010.000

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.

Opus teacher head0.018
GPT teacher head0.238
Teacher spread0.219 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

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".

Quick stats

Citations0
Published2015
Admission routes1
Has abstractyes

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