604 Dissociation of Methane Hydrate in Okhotsk Sea : Survey of Methane Concentration in Sea Water and Sea Ice

Tsukahara, Eiji; Hiraoka, Ayako; Sasaki, Masafumi; Endoh, Noboru

doi:10.1299/jsmehokkaido.2001.41.198

Cited by 2 publications

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“…Platelet ice was first recorded in the literature a half century ago (Dayton et al, ), and while a number of observations have documented the existence, structure, ecology, and regional abundance of platelet ice (Arrigo et al, ; Dempsey et al, ; Gough et al, ; Jeffries & Weeks, ; Leonard et al, ; Smith et al, ), nearly all numerical models exclude it from their treatment of sea ice—with notable exceptions (Dempsey, ; Dempsey et al, ; Kawano & Ohashi, ; Ohashi et al, ; Ohashi & Kawano, ). The most extensive and complete model of platelet ice accretion to date is the work of Wongpan et al (), wherein the authors simulate platelet ice rise dynamics as well as diffusive heat and salt transport within the subice platelet layer.…”

Section: Introductionmentioning

confidence: 99%

Multiphase Reactive Transport and Platelet Ice Accretion in the Sea Ice of McMurdo Sound, Antarctica

2018

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Sea ice seasonally to interannually forms a thermal, chemical, and physical boundary between the atmosphere and hydrosphere over tens of millions of square kilometers of ocean. Its presence affects both local and global climate and ocean dynamics, ice shelf processes, and biological communities. Accurate incorporation of sea ice growth and decay, and its associated thermal and physiochemical processes, is underrepresented in large‐scale models due to the complex physics that dictate oceanic ice formation and evolution. Two phenomena complicate sea ice simulation, particularly in the Antarctic: the multiphase physics of reactive transport brought about by the inhomogeneous solidification of seawater, and the buoyancy driven accretion of platelet ice formed by supercooled ice shelf water onto the basal surface of the overlying ice. Here a one‐dimensional finite difference model capable of simulating both processes is developed and tested against ice core data. Temperature, salinity, liquid fraction, fluid velocity, total salt content, and ice structure are computed during model runs. The model results agree well with empirical observations and simulations highlight the effect platelet ice accretion has on overall ice thickness and characteristics. Results from sensitivity studies emphasize the need to further constrain sea ice microstructure and the associated physics, particularly permeability‐porosity relationships, if a complete model of sea ice evolution is to be obtained. Additionally, implications for terrestrial ice shelves and icy moons in the solar system are discussed.

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Section: Introductionmentioning

confidence: 99%

Multiphase Reactive Transport and Platelet Ice Accretion in the Sea Ice of McMurdo Sound, Antarctica

2018

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“…The accuracy of those models is superb, but the complexity of the mathematics and the demand on computational resources are also at a high level, especially for simulations in three dimensions (3-D). Taking these factors into account, Voronoi dynamics (Ohashi and others, 2004) is a flexible and simple but efficient method to simulate the physical processes of interest here. This technique divides space into a set of points (or seeds) and for each seed there is a corresponding region consisting of all points closer to that seed than to any other.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the crystal growth of platelet sea ice with diffusive heat and mass transfer

Wongpan

Langhorne²,

Dempsey³

et al. 2015

Ann. Glaciol.

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Antarctic coastal sea ice often grows in water that has been supercooled by interaction with an ice shelf. In these situations, ice crystals can form at depth, rise and deposit under the sea-ice cover to form a porous layer that eventually consolidates near the base of the existing sea ice. The least consolidated portion is called the sub-ice platelet layer. Congelation growth eventually causes the subice platelet layer to become frozen into the sea-ice cover as incorporated platelet ice. In this study, we simulate these processes in three dimensions using Voronoi dynamics to govern crystal growth kinetics. Platelet deposition, in situ growth and incorporation into the sea-ice cover are integrated into the model. Heat and mass transfer are controlled by diffusion. We extract and compare spatial-temporal distributions of porosity, salinity, temperature and crystallographic c-axes with observations from McMurdo Sound, Antarctica. The model captures the crystallographic structure of incorporated platelet ice as well as the topology of the sub-ice platelet layer. The solid fraction, which has previously been poorly constrained, is simulated to be �0.22, in good agreement with an earlier estimate of 0.25 � 0.06. This property of the sub-ice platelet layer is important for biological processes, and for the freeboard-thickness relationship around Antarctica.

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604 Dissociation of Methane Hydrate in Okhotsk Sea : Survey of Methane Concentration in Sea Water and Sea Ice

Cited by 2 publications

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Multiphase Reactive Transport and Platelet Ice Accretion in the Sea Ice of McMurdo Sound, Antarctica

Multiphase Reactive Transport and Platelet Ice Accretion in the Sea Ice of McMurdo Sound, Antarctica

Simulation of the crystal growth of platelet sea ice with diffusive heat and mass transfer

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