eprintid: 1419009
rev_number: 39
eprint_status: archive
userid: 608
dir: disk0/01/41/90/09
datestamp: 2014-05-15 11:00:01
lastmod: 2019-10-19 08:09:48
status_changed: 2014-05-15 11:00:01
type: thesis
metadata_visibility: show
item_issues_count: 0
creators_name: Radia, NV
title: Frazil ice formation in the polar oceans
ispublished: unpub
divisions: A01
divisions: B04
divisions: C06
divisions: F57
note: Third party copyright material has been removed from the e-thesis
abstract: Areas of open ocean within the sea ice cover, known as leads and polynyas, expose ocean water directly to the cold atmosphere. In winter, these are regions of high sea ice production, and they play an important role in the mass balance of sea ice and the salt budget of the ocean. Sea ice formation is a complex process that starts with frazil ice crys- tal formation in supercooled waters, which grow and precipitate to the ocean surface to form grease ice, which eventually consolidates and turns into a layer of solid sea ice. This thesis looks at all three phases, concentrating on the rst. Frazil ice comprises millimetre- sized crystals of ice that form in supercooled, turbulent water. They initially form through a process of seeding, and then grow and multiply through secondary nucleation, which is where smaller crystals break o from larger ones to create new nucleii for further growth. The increase in volume of frazil ice will continue to occur until there is no longer super- cooling in the water. The crystals eventually precipitate to the surface and pile up to form grease ice. The presence of grease ice at the ocean surface dampens the e ects of waves and turbulence, which allows them to consolidate into a solid layer of ice. The ice then mostly grows through congelation ice forming beneath the layer of ice. A mathematical model describing the above processes is formulated and used to simulate ice growth. The model consists of conservation equations for mass and heat, with an imposed momentum budget. Simulations are realistic and numerical sensitivity experiments are used to investigate the dependence of ice growth on the ambient environment.
date: 2014-02-28
vfaculties: VMPS
oa_status: green
full_text_type: other
thesis_class: doctoral_open
language: eng
thesis_view: UCL_Thesis
dart: DART-Europe
primo: open
primo_central: open_green
verified: verified_manual
elements_source: Manually entered
elements_id: 926623
lyricists_name: Radia, Nikhil
lyricists_id: NVRAD26
full_text_status: public
pagerange: ? - ?
pages: 167
institution: UCL (University College London)
department: Earth Sciences
thesis_type: Doctoral
citation:        Radia, NV;      (2014)    Frazil ice formation in the polar oceans.                   Doctoral thesis , UCL (University College London).     Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/1419009/1/Radia_NikhilThesisFinal_redacted.pdf