scholarly journals Greenland Geothermal Heat Flow Database and Map (Version 1)

2021 ◽  
Author(s):  
William Colgan ◽  
Agnes Wansing ◽  
Kenneth Mankoff ◽  
Mareen Lösing ◽  
John Hopper ◽  
...  
Keyword(s):  
Heat Flow ◽  
Flow Model ◽  
Horizontal Resolution ◽  
Geothermal Heat ◽  
Flow Measurements ◽  
Flow Models ◽  
The North ◽  
Marine Areas ◽  
Heat Flow Model

Abstract. We compile, analyse and map all available geothermal heat flow measurements collected in and around Greenland into a new database of 419 sites and generate an accompanying spatial map. This database includes 290 sites previously reported by the International Heat Flow Commission (IHFC), for which we now standardize measurement and metadata quality. This database also includes 129 new sites, which have not been previously reported by the IHFC. These new sites consist of 88 offshore measurements and 41 onshore measurements, of which 24 are subglacial. We employ machine learning to synthesize these in situ measurements into a gridded geothermal heat flow model that is consistent across both continental and marine areas in and around Greenland. This model has a native horizontal resolution of 55 km. In comparison to five existing Greenland geothermal heat flow models, our model has the lowest mean geothermal heat flow for Greenland onshore areas (44 mW m–2). Our model’s most distinctive spatial feature is pronounced low geothermal heat flow (< 40 mW m–2) across the North Atlantic Craton of southern Greenland. Crucially, our model does not show an area of elevated heat flow that might be interpreted as remnant from the Icelandic Plume track. Finally, we discuss the substantial influence of paleoclimatic and other corrections on geothermal heat flow measurements in Greenland. The in-situ measurement database and gridded heat flow model, as well as other supporting materials, are freely available from the GEUS DataVerse (https://doi.org/10.22008/FK2/F9P03L; Colgan and Wansing, 2021).

scholarly journals Antarctic geothermal heat flow model: Aq1.

2020 ◽  
Author(s):  
Tobias Stål ◽  
Anya M. Reading ◽  
Jacqueline A. Halpin ◽  
Joanne M. Whittaker
Keyword(s):  
Heat Flow ◽  
Flow Model ◽  
Geothermal Heat ◽  
Heat Flow Model

scholarly journals Basal melt at NorthGRIP modeled from borehole, ice-core and radio-echo sounder observations

2003 ◽  
Vol 37 ◽  
pp. 207-212 ◽  
Author(s):  
Dorthe Dahl-Jensen ◽  
Niels Gundestrup ◽  
S. Prasad Gogineni ◽  
Heinz Miller
Keyword(s):  
Heat Flow ◽  
Flow Model ◽  
Flow Line ◽  
Ice Core ◽  
Time Dependent ◽  
Surface Velocity ◽  
Geothermal Heat ◽  
The North ◽  
Annual Layer ◽  
Dependent Flow

AbstractFrom temperature measurements down through the 3001 m deep borehole at the North Greenland Icecore Project (NorthGRIP) drill site, it is now clear that the ice at the base, 3080 m below the surface, is at the pressure-melting point. This is supported by the measurements on the ice core where the annual-layer thicknesses show there is bottom melting at the site and upstream from the borehole. Surface velocity measurements, internal radio-echo layers, borehole and ice-core data are used to constrain a time-dependent flow model simulating flow along the north-northwest-trending ice-ridge flow-line, leading to the NorthGRIP site. Also time-dependent melt rates along the flowline are calculated with a heat-flow model. The results show the geothermal heat flow varies from 50 to 200 mW m–2 along the 100km section of the modeled flowline. The melt rate at the NorthGRIP site is 0.75 cm a–1, but the deep ice in the NorthGRIP core originated 50 km upstream and has experienced melt rates as high as 1.1 cm a–1.

scholarly journals Critical Tectonic Limits for Geothermal Aquifer Use: Case Study from the East Slovakian Basin Rim

Resources ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 31
Author(s):  
Stanislav Jacko ◽  
Roman Farkašovský ◽  
Igor Ďuriška ◽  
Barbora Ščerbáková ◽  
Kristína Bátorová
Keyword(s):  
Heat Flow ◽  
Pannonian Basin ◽  
Open Fractures ◽  
Water Type ◽  
Geothermal Heat ◽  
The North ◽  
Heat System ◽  
Volcanic Chain ◽  
Saline Solutions

The Pannonian basin is a major geothermal heat system in Central Europe. Its peripheral basin, the East Slovakian basin, is an example of a geothermal structure with a linear, directed heat flow ranging from 90 to 100 mW/m2 from west to east. However, the use of the geothermal source is limited by several critical tectono-geologic factors: (a) Tectonics, and the associated disintegration of the aquifer block by multiple deformations during the pre-Paleogene, mainly Miocene, period. The main discontinuities of NW-SE and N-S direction negatively affect the permeability of the aquifer environment. For utilization, minor NE-SW dilatation open fractures are important, which have been developed by sinistral transtension on N–S faults and accelerated normal movements to the southeast. (b) Hydrogeologically, the geothermal structure is accommodated by three water types, namely, Na-HCO3 with 10.9 g·L−1 mineralization (in the north), the Ca-Mg-HCO3 with 0.5–4.5 g·L−1 mineralization (in the west), and Na-Cl water type containing 26.8–33.4 g·L−1 mineralization (in the southwest). The chemical composition of the water is influenced by the Middle Triassic dolomite aquifer, as well as by infiltration of saline solutions and meteoric waters along with open fractures/faults. (c) Geothermally anomalous heat flow of 123–129 °C with 170 L/s total flow near the Slanské vchy volcanic chain seems to be the perspective for heat production.

Implications for the lithospheric structure of Greenland by applying different heat flow models

2021 ◽  
Author(s):  
Agnes Wansing ◽  
Jörg Ebbing ◽  
Mareen Lösing ◽  
Sergei Lebedev ◽  
Nicolas Celli ◽  
...  
Keyword(s):  
Heat Flow ◽  
Heat Dissipation ◽  
Ice Sheet ◽  
Magnetic Data ◽  
Similarity Function ◽  
Lithospheric Structure ◽  
Temperature Structure ◽  
Geothermal Heat ◽  
Flow Models ◽  
Ice Sheet Dynamics

&lt;p&gt;The lithospheric structure of Greenland is still poorly known due to its thick ice sheet, the sparseness of seismological stations, and the limitation of geological outcrops near coastal areas. As only a few geothermal measurements are available for Greenland, one must rely on geophysical models. Such models of Moho and LAB depths and sub-ice geothermal heat-flow vary largely.&lt;/p&gt;&lt;p&gt;Our approach is to model the lithospheric architecture by geophysical-petrological modelling with LitMod3D. The model is built to reproduce gravity observations, the observed elevation with isostasy assumptions and the velocities from a tomography model. Furthermore, we adjust the thermal parameters and the temperature structure of the model to agree with different geothermal heat flow models. We use three different heat flow models, one from machine learning, one from a spectral analysis of magnetic data and another one which is compiled from a similarity study with tomography data.&lt;/p&gt;&lt;p&gt;For the latter, a new shear wave tomography model of Greenland is used. Vs-depth profiles from Greenland are compared with velocity profiles from the US Array, where a statistical link between Vs profiles and surface heat flow has been established. A similarity function determines the most similar areas in the U.S. and assigns the mean heat-flow from these areas to the corresponding area in Greenland.&lt;/p&gt;&lt;p&gt;The geothermal heat flow models will be further used to discuss the influence on ice sheet dynamics by comparison to friction heat and viscous heat dissipation from surface meltwater.&lt;/p&gt;

scholarly journals Heat flow model for pulsed laser melting and rapid solidification of ion implanted GaAs

2010 ◽  
Vol 108 (1) ◽  
pp. 013508 ◽  
Author(s):  
Taeseok Kim ◽  
Manoj R. Pillai ◽  
Michael J. Aziz ◽  
Michael A. Scarpulla ◽  
Oscar D. Dubon ◽  
...  
Keyword(s):  
Heat Flow ◽  
Rapid Solidification ◽  
Flow Model ◽  
Pulsed Laser ◽  
Laser Melting ◽  
Heat Flow Model ◽  
Ion Implanted

scholarly journals The role of mesoscale eddies time and length scales on phytoplankton production

2010 ◽  
Vol 17 (2) ◽  
pp. 177-186 ◽  
Author(s):  
V. Pérez-Muñuzuri ◽  
F. Huhn
Keyword(s):  
Flow Model ◽  
North Atlantic Ocean ◽  
Coupled Model ◽  
Optimal Time ◽  
Phytoplankton Production ◽  
Correlated Noise ◽  
Length Scales ◽  
Flow Models ◽  
The North ◽  
Qualitative Interaction

Abstract. Horizontal mixing has been found to play a crucial role in the development of spatial plankton structures in the ocean. We study the influence of time and length scales of two different horizontal two-dimensional (2-D) flows on the growth of a single phytoplankton patch. To that end, we use a coupled model consisting of a standard three component ecological NPZ model and a flow model able to mimic the mesoscale structures observed in the ocean. Two hydrodynamic flow models are used: a flow based on Gaussian correlated noise, for which the Eulerian length and time scales can be easily controlled, and a multiscale velocity field derived from altimetry data in the North Atlantic ocean. We find the optimal time and length scales for the Gaussian flow model favouring the plankton spread. These results are used for an analysis of a more realistic altimetry flow. We discuss the findings in terms of the time scale of the NPZ model, the qualitative interaction of the flow with the reaction front and a Finite-Time Lyapunov Exponent analysis.

Cold-specific feeding response of rats to cold exposure and energy density of body weight change

1981 ◽  
Vol 51 (2) ◽  
pp. 327-334 ◽  
Author(s):  
S. D. Morrison
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Density ◽  
Heat Flow ◽  
Cold Exposure ◽  
Weight Change ◽  
Flow Model ◽  
Energy Yield ◽  
Body Weight Change ◽  
Heat Flow Model

The increased food intake of rats exposed to cold is the result of increased intake due to cold (cold-specific compartment; A) and decreased intake due to simultaneously decreased body weight (weight-specific compartment; B). The two compartments are evaluated at 5, 13, and 17 degrees C. B is evaluated as the food intake of theoretical, isogravimetric control (identical to cold-exposed rats with respect to body weight and rate of change of body weight and identical to nonexposed rats in all other respects) that takes into account both the change in energy expenditure due to decreased body weight and the energy yield from tissue catabolism represented by change of body weight. A is the observed food intake minus B. A theoretical heat-flow model, in which expected changes in heat flow during cold exposure drive food intake to maintain or restore preexposure body weight status, corroborated the partition derived from experimental data. However, both the experimental results and the heat-flow model imply that the energy density of body weight change is negatively correlated with rate of body weight change. The energy density of weight change is high with high rates of weight loss and low with high rats of weight gain.

scholarly journals In situ determination of heat flow in unconsolidated sediments

Geophysics ◽  
1981 ◽  
Vol 46 (1) ◽  
pp. 76-83 ◽  
Author(s):  
J. H. Sass ◽  
J. P. Kennelly ◽  
W. E. Wendt ◽  
T. H. Moses ◽  
J. P. Ziagos
Keyword(s):  
Heat Flow ◽  
Thermal Gradient ◽  
Equilibrium Temperature ◽  
Unconsolidated Sediments ◽  
Heat Sources ◽  
Geothermal Resources ◽  
Flow Measurements ◽  
Thermal Measurements

Subsurface thermal measurements are the most effective, least ambiguous tools for locating geothermal resources. Measurements of thermal gradient in the upper few tens of meters can delineate the major anomalies, but it is also desirable to combine these gradients with reliable estimates of thermal conductivity, to provide data on the energy flux and to constrain models of the heat sources responsible for the anomalies. Problems associated with such heat flow measurements include the economics of casing or grouting holes, the long waits and repeated visits necessary to obtain equilibrium temperature values, the possible legal liability arising from disturbance of aquifers, the hazards presented by pipes protruding from the ground, and the security problems associated with leaving cased holes open for periods of weeks to months.

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