Modeling Impacts of Thaw Lakes to Ground Thermal Regime in Northern Alaska

Zhou, Wendy; Huang, Scott L.

doi:10.1061/(asce)0887-381x(2004)18:2(70)

Cited by 22 publications

(14 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A geothermal heat flux of 0.055 W m −2 , a value measured from deep beneath thaw lake terrain in northern Alaska [ Lachenbruch et al , 1982], is applied to the bottom boundary, and an equilibrium temperature profile imposed as an initial condition. Thermal conductivity, k and heat capacity, C , are 1.17 W m −1 K −1 and 4.0 × 10 8 J kg −1 K −1 in the frozen state, and 0.33 W m −1 K −1 and 6.7 × 10 8 J kg −1 K −1 in the unfrozen state, which are within the range of thermal parameters used by Lachenbruch et al [1988] and Zhou and Huang [2004]. These assume k and C values for soil components summarized by Williams and Smith [1991], with volumetric proportions: 10% organic material, 40% mineral soil and 50% ice.…”

Section: Modeled Taliks and Bathymetrysupporting

confidence: 57%

“… Ling and Zhang [2003] use a two‐dimensional finite element model to explore temperature profiles in permafrost as a function of lake temperature and time, predicting talik depths of 28 to 53 m beneath a lake of 800 m diameter after 3000 a, depending on water temperature. Zhou and Huang [2004] examine the response of varying air temperature on lake ice and talik development, showing lake ice thickness is closely linked to air temperature, and isotherms beneath a shallow lake (3 m, with lake ice thickness <2 m) migrate downward during the winter. One difficulty with existing dynamic numerical and steady state analytical models is that lake deepening caused by thaw subsidence in the talik is not addressed, even though this changes the boundaries and volume of the heat source, the lake.…”

Section: Thaw Lake Morphology and Taliksmentioning

confidence: 99%

See 1 more Smart Citation

Time‐dependent morphology of thaw lakes and taliks in deep and shallow ground ice

2008

View full text Add to dashboard Cite

[1] The shape and depth of thaw lake basins depends on lake age, on whether the talik (thaw bulb) is at steady state, and on the distribution of ice in the ground. To investigate implications of this broad hypothesis, we use a numerical model of conductive heat transfer, phase change, and thaw subsidence of ice-rich sediment beneath a lake in cross section. For ground thermal properties with lake temperatures and dimensions consistent with measurements, modeled talik depth approximately increases with ffiffiffiffiffiffiffiffi ffi time p except in lakes in deep ground ice which deepen more rapidly because of consolidation on thawing. In deep ground ice environments, basins achieve depths of %20 m in %5 ka. Expanding lakes with disequilibrium taliks have deep basins with broad, 100+ m wide, inclined margins. In shallow ground ice settings (either original epigenetic ice or in permafrost that has reformed in drained basins), lakes are <3 m deep and flat bottomed. Unaffected by preexisting topography and ground ice variations, first-generation lakes in deep ground ice are rounder and grow larger in area than later-generation lakes. These predictions are consistent with GPS, sonar, and remote sensing measurements of bathymetry and plan view shape of first-and later-generation lakes in substrates with deep syngenetic ground ice (Pleistocene loess, northern Seward Peninsula, Alaska) and shallow epigenetic ice (Yukon Arctic coastal plain).Citation: West, J. J., and L. J. Plug (2008), Time-dependent morphology of thaw lakes and taliks in deep and shallow ground ice,

show abstract

Section: Modeled Taliks and Bathymetrysupporting

confidence: 57%

Section: Thaw Lake Morphology and Taliksmentioning

confidence: 99%

Time‐dependent morphology of thaw lakes and taliks in deep and shallow ground ice

2008

View full text Add to dashboard Cite

show abstract

“…The simulated active layer depth and maximum lake ice thickness are 0.6 m [ Hopkins , 1949; Hopkins et al , 1955; Plug and West , 2009] and 1.5 m [ Zhou and Huang , 2004; Plug and West , 2009]. The simulated mean annual deep water temperature is 3°C, which is within the range of observed thermokarst lake bottom temperatures (1.5°C to 5.5°C) [ Burn , 2002, 2005], is the suggested average for deep water [ Burn , 2005], and is within the range of values used in previous simulations [ Ling and Zhang , 2003, 2004; Zhou and Huang , 2004; West and Plug , 2008; Plug and West , 2009; Taylor et al , 2008]. These later parameters also can vary systematically in the model with a change in mean annual temperature or amplitude from an assigned reference value using the accumulated degree days of thaw/freeze; however, no climate change was imposed in the simulations shown here.…”

Section: Simulation Setupmentioning

confidence: 99%

Simulating the decadal‐ to millennial‐scale dynamics of morphology and sequestered carbon mobilization of two thermokarst lakes in NW Alaska

2012

View full text Add to dashboard Cite

[1] Thermokarst lakes alter landscape topography and hydrology in widespread permafrost regions and mobilize significant permafrost carbon pools, including releasing methane (CH 4 ) to the atmosphere. Despite this, the dynamics of lake evolution, permafrost thawing, and carbon mobilization are not well known. We present a 3-D numerical model of thermokarst lakes on organic-rich yedoma permafrost terrains with surface water flow and pooling naturally defining lakes that deepen, expand laterally, and drain due to talik formation, bank retreat, and both gradual and catastrophic drainage. We predict the 3-D pattern of microbial methane production within the talik over time. As a first model test and calibration, beginning with small protolakes, we simulated 10,000 years of evolution of Pear and Claudi lakes, two neighboring thermokarst features on the northern Seward Peninsula, Alaska. Simulated lakes approximated observed bathymetry, but results are sensitive to initial topography and soil ice content. Local topography caused markedly different dynamics for the two lakes. Pear expanded rapidly across low-relief topography, fully drained multiple times, and released little methane in later stages due to Pleistocene carbon depletion by the first and largest lake generation. Claudi grew slowly and continuously across high-relief topography, forming high subaerial banks; partial drainages left remnant horseshoe lakes that continued to expand into virgin yedoma, mobilizing carbon at roughly the same rate irrespective of lake drainage. The $2Â discrepancy between simulated CH 4 production and observed emission rates in Claudi likely results from misestimation of hot spot ebullition, labile carbon content, CH 4 :CO 2 production ratio, or microbial CH 4 oxidation.

show abstract

“…Lake ice thickness is primarily controlled by surface air temperature, but water temperature and the depth, density and albedo of snow also play a role [ Duguay et al , 2003]. Winter lake ice thickness is set to 1.5 m in the model, consistent with measured lake ice in northern Alaska and northwestern Canada where MAAT is −6°C [ Allen , 1977; Jeffries et al , 1996; Zhou and Huang , 2004]. The interannual variability of lake ice in natural lakes is sufficiently small in magnitude (the 1 σ variability was 8.2 cm over 12 years of measurement for a lake inland of Shingle Point, in the YCP field area [ Allen , 1977]) that the annual maximum ice thickness is held constant in each model scenario.…”

Section: Modelmentioning

confidence: 99%

Thaw lake expansion in a two‐dimensional coupled model of heat transfer, thaw subsidence, and mass movement

Plug¹,

West²

2009

J. Geophys. Res.

View full text Add to dashboard Cite

[1] Thaw lakes, widespread in permafrost lowlands, expand their basins by conduction of heat from warm lake water into adjacent permafrost, subsidence of icy permafrost on thawing, and movement of thawed sediment from lake margins into basins by diffusive and advective mass wasting. We describe a cross-sectional numerical model with thermal processes and mass wasting. To test the model and provide an initial investigation of its utility, the model is driven using historical daily temperatures and permafrost conditions for the northern Seward Peninsula, Alaska (NSP; thick syngenetic ice, mean annual air temperature (MAAT) À6°C) and Yukon coastal plain (YCP; thin epigenetic ice, MAAT À10°C). In the model, lakes develop dynamic equilibrium profiles that are independent of initial morphology. These profiles migrate outward episodically and match the morphology of profiles from lakes that were measured at each site. Modeled NSP lakes expand more rapidly than YCP lakes (0.26 versus 0.10 m a À1 ) under respective modern climates. When identical climates are imposed, NSP lakes still grow more rapidly because their deeper basins and steeper bathymetric slopes move thawed insulating sediment away from the lake margin. In sensitivity tests, an increase of 3°C in MAAT causes 2.5Â (NSP) and 1.6Â (YCP) faster expansion of lakes. An 8°C decrease essentially halts expansion for both sites, consistent with paleostudies which attribute basins to postglacial warming. In the model, basins expand monotonically but lakes do not. The 1s interannual variability of lake expansion is 0.51 (NSP) and 0.44 m a À1 (YCP), with single year rates of up to ±8 m occurring because of instabilities from thermal/mass movement coupling even under a stationary climate. This variability is likely a minimum estimate, compared to natural variability, and suggests that long measurement time series, of basins not lake surfaces, would best detect thermokarst acceleration resulting from a climate change.Citation: Plug, L. J., and J. J. West (2009), Thaw lake expansion in a two-dimensional coupled model of heat transfer, thaw subsidence, and mass movement,

show abstract

Modeling Impacts of Thaw Lakes to Ground Thermal Regime in Northern Alaska

Cited by 22 publications

References 11 publications

Time‐dependent morphology of thaw lakes and taliks in deep and shallow ground ice

Time‐dependent morphology of thaw lakes and taliks in deep and shallow ground ice

Simulating the decadal‐ to millennial‐scale dynamics of morphology and sequestered carbon mobilization of two thermokarst lakes in NW Alaska

Thaw lake expansion in a two‐dimensional coupled model of heat transfer, thaw subsidence, and mass movement

Contact Info

Product

Resources

About