Formulation of a model for pore water convection in thawing subsea permafrost by W. D. Harrison

Cover of: Formulation of a model for pore water convection in thawing subsea permafrost | W. D. Harrison

Published by Versuchsanstalt für Wasserbau, Hydrologie, und Glaziologie in Zürich .

Written in English

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Subjects:

  • Frozen ground.,
  • Ocean bottom.,
  • Glaciers.

Edition Notes

Bibliography: p. 33.

Book details

StatementW.D. Harrison. Glacier flow : recent developments / K. Hutter.
SeriesMitteilungen der Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie an der Eidgenössischen Technischen Hochschule Zürich ;, Nr. 57
ContributionsHutter, Kolumban.
Classifications
LC ClassificationsGB642 .H37 1982
The Physical Object
Pagination33 p. :
Number of Pages33
ID Numbers
Open LibraryOL3229050M
LC Control Number83140950

Download Formulation of a model for pore water convection in thawing subsea permafrost

FORMULATION OF A MODE L FOR PORE WATER CONVECTION IN THAWING SUBSEA PERMAFROST W.D. Harrison ABSTRACT Ice-bearing permafrost exists in a transient state under much of the Beaufort Sea shelf.

A thawed layer usually underlies the sea bed. Its rate of evolution depends critically on the rate. Convection in Thawing Subsea Permafrost. relatively fresh water motion in a layer of salty subsea sediments. within the framework of an enthalpy formulation, to the solutions of model.

Upon thawing, water is released and pore pressures are generated. Then, the state of the just-thawed soil is determined by three parameters, namely the initial void ratio, e 0, the initial permeability, k 0, and the initial effective isotropic stress, p′ 0.

Also known as residual stress, the latter is defined as the effective stress in a soil Author: Marianna Loli, Angelos Tsatsis, Rallis Kourkoulis, Ioannis Anastasopoulos. The work of B.S. was partly supported by the U.S.

Army Research Office through the Mathematical Sciences Institute of Cornell University. Double diffusive porous penetrative convection REFERENCES [I] W.

HARRISON, Formulation of a model for pore water convection in thawing subsea by: Anomalous features in the model of second grade fluids, Convection in thawing subsea permafrost, Formulation of a model for pore water convection in thawing subsea permafrost, ().

Hydrodynamic and hydromagnetic stability, Dover publications. Author: Paula Budu. ESAS seabed deposits and the documented thawing rates of subsea permafrost reported recently [22]. The purpose of this paper is to introduc e the ESAS permafrost–hydrates system, which is.

Subsea permafrost was discovered in individual boreholes of the South Kara Sea in water depth of up to m. Modeling of permafrost generation at the South Kara Sea shelf suggests that a We propose two mechanisms for the observed fluid flow: i) convection of thaw water from subsea permafrost; and/or ii) lateral sub-permafrost ground water discharge marking the outer extent of.

To replicate physical permafrost models and compare the efficiency of thawing by convection versus thawing by conduction, eight cells were designed and filled with different saturated soils. Subsea permafrost has been subjected to additional warming induced by sea water; in the ESAS, sea water is much warmer than air (mean annual air temperature of −10 °C vs.

mean annual sea water temperature of −1 °C). Consequently, the subsea permafrost has warmed by up to 17 °C during the last 12 kyrs [23,32]. We use the numerical model to evaluate the evolution of temperature, pore water salinity, pressure, fluid velocity, permafrost distribution, and gas hydrate stability.

The model is time dependent and based on the finite volume method previously documented in Frederick and Buffett [ ], with improvements and changes noted as follows. of thawing subsea permafrost and the salinity profiles in thawed layer to be characteristic of convective processes, and who used simple theory to show that a diffusive regime is often unstable to convection; and Musgrave and Reeburgh [], who find time-varying temperature fields in lake sedi.

Submarine groundwater discharge (SGD) is a large‐scale, buoyancy‐driven, offshore flow of terrestrial groundwater. If SGD occurs within the permafrost‐bearing sediments of the circum‐Arctic shelf, such fluid circulation may transport large amounts of dissolved methane to the circum‐Arctic shelf, aiding the formation of permafrost‐associated gas hydrate.

Harrison() Harrison, W. D.: Formulation of a model for pore water convection in thawing subsea permafrost, Mitteilungen der Versuchsanstalt für.

Thus, permafrost thaw or changing patterns of seasonal subsurface ice can result in new or enhanced surface water distributions (Connon et al., ) and can modify subsurface water pathways (Kurylyk et al., a, Frampton and Destouni, ) which can thereby affect the hydrologic and hydrogeologic connectivity of a landscape.

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When convection begins in the unstable layer the motions penetrate into the stable layer. Penetrative convection has applications in stellar regions (see e.g.) and in geophysical problems, including modelling thawing subsea permafrost (see e.g.).

Permafrost accounts for approximately 24% of the exposed land area in the Northern Hemisphere [].Permafrost regions have different hydrology and hydrology-related conditions compared to non-permafrost regions [4,5].Permafrost can affect many hydrological processes in Arctic and sub-Arctic environments [], for example, surface and subsurface water fluxes [4,7,8,9].

Forced Convection with Evaporation Condensation Spaces Filled with Fluid and Fibers Coated with a Phase-Change Material 11 Geophysical Aspects Snow Patterned Ground Thawing Subsea Permafrost Magma Production and Magma Chambers.

Also, the applied approach computes the volumetric content of water which changes its phase during freezing or thawing. Water content of liquid water that is tightly bound to soil particles and is not changing its phase can not be estimated within the proposed model.

Additionally, we used 1-D assumption regarding the heat diffusion in the. Forced Convection - water and liquids: 50 to Free Convection - gases and dry vapors: 5 to Free Convection - water and liquids: 50 to Air: Engineering Book Store Engineering Forum Excel App.

Downloads Online Books & Manuals Engineering. Massmann, G., Simmons, C., Love, A., Ward, J. and James-Smith, J. On the variable density surface water-groundwater interaction: a theoretical analysis of mixed convection in a stably-stratified fresh surface water saline groundwater discharge zone.

Third Edition. Springer Science Business Media, Inc., p. ISBN:ISBN: This book provides a user-friendly introduction to convection in porous media, such as fibrous insulation, geological strata, and catalytic reactors.

The presentation is. Upon thaw, the ice changes to water; the volume of the pore fluid decreases by about 9%; and the pore pressure decreases. To maintain equilibrium, the soil compacts, increasing intergranular forces until a new stress state is reached that balances the surrounding earth pressures.

The loading of the permafrost is the pore-pressure change caused. Meanwhile, the infiltrated water helps warm up the foundation soils including the permafrost and results in thawing and settlement of the permafrost, which leads to more settlement and misalignment of the disjointed lining segments.

The misaligned lining further reduces the drainage capacity and allows more water to infiltrate the ground. The East Siberian Arctic Shelf (ESAS) hosts large yet poorly quantified reservoirs of subsea permafrost and associated gas hydrates.

It has been suggested that the global-warming induced thawing and dissociation of these reservoirs is currently releasing methane (CH 4) to the shallow coastal ocean and ultimately the r, a major unknown in assessing the contribution of this CH 4.

The EOS for a given type of gas hydrate is a function of the hydrate‐forming gases that are present, the salinity of the pore water, the size of pore spaces, and other factors. Higher‐order hydrocarbons (e.g., ethane or C2, and propane or C3) form hydrates over a broader range of temperatures than pure methane (C1) (Sloan & Koh, ).

During an average open‐water season of 4 months, between ± (PF MIN + SW) and ± (PF ORG + SW) mg CO 2 ‐C/gdw are produced from thawing permafrost in seawater at 4 °C (Table 1 and Figure 3). The produced CO 2 from permafrost thaw in seawater. Therefore, the >0 ∘ C bottom water temperatures common to the present-day Pechora Sea may have existed from 7 to 5 ka on the southwestern Kara shelf and provided thawing of permafrost from above.

The distribution of permafrost also depends on deep heat flux, which may reach 50–60 mW m −2 over the greatest part of the Kara shelf.

If the observed warming of the permafrost underlying boreal forest ecosystems in Alaska continues, then additional permafrost will thaw. Where the permafrost is ice-rich (roughly 50% ice), thawing changes the ice to water, creating a mud slurry that cannot support the weight of overlying soil or vegetation, thereby degrading the physical.

1 Introduction. Frozen soil (e.g., permafrost) covers more than 20% of the Earth's land surface, and approximately 50% when seasonal and other forms of transient freezing are included [Zhang et al., ].The importance of freezing and thawing processes has long been recognized.

TEMP/W analyses can obtain water fluxes from a SEEP/W analysis to simulate heat transfer via forced convection.

Density-Dependent Flow. In density-dependent fluid flow, the density of the water is dependent on the temperature.

The water velocity in turn influences the distribution of heat throughout the domain. Thus, heat and water flow are. I lead the USGS Gas Hydrates Project, which is jointly funded by the Coastal-Marine Hazards and Resources Program and the Energy Resources Program.

Project scientists in Woods Hole, Denver, Menlo Park, and Santa Cruz study natural methane hydrate. Hydrate is a potential energy resource, has synergies with global climate, and may play a role in some marine geohazards.

The total thickness of present and relict permafrost exceeds 20 m within the 1 m isobath, is no more than 10 m at sea depths between 0 and 2–3 m, and pinches out seaward in deeper water; the depth to subsea permafrost within 3 m water depths is 5 to 15 m or more (Baulin, ).

A field experiment was constructed at the Diavik Diamond Mine in northern Canada to investigate water flow through unsaturated piles of mine waste rock in a region of permafrost. Two test piles 15 m-high were built on collection systems 60 m by 50 m, each consisting of lysimeters and a large impermeable HDPE liner, and instrumentation was installed within the piles to measure moisture content.

Verification is given of a water pressures calculation and the cutting forces. The water vacuum pressures are determined with equation (4) derived by Van Os (, [24, 25]). The water pore pressure calculation is performed with the finite difference method, in which the height of.

Convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. There are two types of convection: natural and forced convection.

This study draws on years of field observation at Scotty Creek, NWT to explain: 1) a conceptual model of the hydrological interactions among the major terrain types of wetland-dominated discontinuous permafrost that typify the southern margin of permafrost; 2) soil thaw and re-freezing processes that control runoff generation from permafrost.

A % increase in the salt content of water means that the water’s freezing point drops °C, so ice age permafrost could exist in the submersed sea floor. Elson Lagoon Pt. Barrow. Approximately % of the very warm permafrost and 96 % of the likely thawing permafrost has degraded to seasonally frozen ground.

The mean elevations of the very cold, cold, cool, warm, very warm, and likely thawing permafrost areas increased by 88, 97,and m, respectively. Porosity may be classified according to the mode of origin as “original” and “induced”. The original porosity is that developed in the process of deposition that forms the rock, while induced or secondary porosity added at a later stage by some geologic and chemical inter-granular porosity of sandstones and the inter-crystalline and oolitic porosity of some limestones.The pore-water pressure conditions from the seepage analysis can be used in the stability analysis, and both analyses may be present in the same project file.

Enhanced AIR/W formulation with new material model and boundary condition such as modeling forced heat convection with flowing air and water or modeling density-driven groundwater.Dissolved CH4 in the permafrost pore water immediately upon thaw was ~ mM in all treatments, and remained at this concentration in the saturated cores.

In in situ water saturation treatments, however, pore water CH4 concentrations decreased from ± mM to ± mM over the course of three weeks without release into the core headspace.

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