Estimating winter ebullition bubble volume in lake ice using ground-penetrating radar

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. H13-H25 ◽  
Author(s):  
Nadia Fantello ◽  
Andrew D. Parsekian ◽  
Katey M. Walter Anthony
Keyword(s):  
Ground Penetrating Radar ◽  
Growth Models ◽  
Field Measurements ◽  
Gas Content ◽  
Atmospheric Methane ◽  
Lake Ice ◽  
Electromagnetic Models ◽  
Lake Bottom Sediments ◽  
Ground Penetrating ◽  
Gas Volume

Freshwater lakes are an important source of atmospheric methane ([Formula: see text]); however, uncertainties associated with quantifying fluxes limit the accuracy of climate warming projections. Among emission pathways, ebullition (bubbling) is the principal and most challenging to account for given its spatial and temporal patchiness. When lakes freeze, many methane-rich bubbles escaping from lake-bottom sediments are temporarily trapped by downward-growing lake ice. Because bubble position is then seasonally fixed, we postulate that it should be possible to locate bubbles using a geophysical approach sensitive to perturbations in the ice-water interface and ice sheet structure generated by bubbles. We use ground-penetrating radar (GPR) to noninvasively quantify the amount of ebullition gas present in lake ice. To do this, an appropriate petrophysical transformation is required that relates radar wave velocity and volumetric gas content. We use laboratory experiments to show that electromagnetic models and volumetric mixing formulas were good representations of the gas volume-permittivity relationship. We found a standard deviation in dielectric permittivity between the models of 0.03, 0.03, and 0.02 for 20%, 50%, and 70% gas content, respectively. Second, by combining two GPR geometries (common and multioffset), we were able to locate bubbles and estimate gas volume with low uncertainty, with [Formula: see text] being the lowest uncertainty found and [Formula: see text] the largest. Finally, we found that GPR reflection patterns were associated with different previously identified ice-bubble classes. These geophysical results coupled with ancillary field measurements and ice-growth models also suggest how GPR can contribute to estimates of seasonal and annual ebullition fluxes over large spatiotemporal scales within and among lakes, thereby helping to reduce uncertainties in upscaled estimates of ecosystem methane emissions.

scholarly journals Ground penetrating radar detection of subsnow slush on ice-covered lakes in interior Alaska

2012 ◽  
Vol 6 (6) ◽  
pp. 1435-1443 ◽  
Author(s):  
A. Gusmeroli ◽  
G. Grosse
Keyword(s):  
Ground Penetrating Radar ◽  
Geophysical Methods ◽  
Arctic Region ◽  
Water Harvesting ◽  
Lake Ice ◽  
Wet Snow ◽  
Dry Conditions ◽  
Ground Penetrating ◽  
Ice Water

Abstract. Lakes are abundant throughout the pan-Arctic region. For many of these lakes ice cover lasts for up to two thirds of the year. The frozen cover allows human access to these lakes, which are therefore used for many subsistence and recreational activities, including water harvesting, fishing, and skiing. Safe traveling condition onto lakes may be compromised, however, when, after significant snowfall, the weight of the snow acts on the ice and causes liquid water to spill through weak spots and overflow at the snow-ice interface. Since visual detection of subsnow slush is almost impossible our understanding on overflow processes is still very limited and geophysical methods that allow water and slush detection are desirable. In this study we demonstrate that a commercially available, lightweight 1 GHz, ground penetrating radar system can detect and map extent and intensity of overflow. The strength of radar reflections from wet snow-ice interfaces are at least twice as much in strength than returns from dry snow-ice interface. The presence of overflow also affects the quality of radar returns from the base of the lake ice. During dry conditions we were able to profile ice thickness of up to 1 m, conversely, we did not retrieve any ice-water returns in areas affected by overflow.

Evidence for glacial geological controls on the hydrology of Maine (USA) peatlands

Geology ◽  
2020 ◽  
Vol 48 (8) ◽  
pp. 771-776
Author(s):  
Xi Chen ◽  
Xavier Comas ◽  
Andrew Reeve ◽  
Lee Slater
Keyword(s):  
Ground Penetrating Radar ◽  
Peat Soil ◽  
Spatial Association ◽  
Geochemical Data ◽  
Atmospheric Methane ◽  
Multiple Sources ◽  
Ch4 Production ◽  
Geological Factors ◽  
Ground Penetrating

Abstract Freshwater pools commonly form eccentric crescent patterns in peatlands, an important atmospheric methane (CH4) source, and show an apparent spatial association with eskers in some deglaciated regions. However, the role of underlying permeable glacial deposits such as eskers in regulating hydrogeology, and perhaps even carbon cycling, in peatlands is rarely considered. In this study, ground-penetrating radar imaging and direct coring confirmed that clustered pools coincide with buried esker crests in contact with peat soil in Caribou Bog and Kanokolus Bog in Maine (USA). Hydraulic head and geochemical data combined with lidar indicate vertical water flow from shallow peat toward the permeable esker crests, suggesting enhanced downward transport of labile organic carbon that presumably accelerates rates of methanogenesis in deep peat. Eskers might therefore serve as proxies for enhanced CH4 production in deep peat, as supported by differences in dissolved CH4 profiles depending on proximity to pools. Geographic data compiled from multiple sources suggest that many peatlands with eccentric pools appear to be located proximal to esker systems in Maine and Fennoscandia. These geological factors may be important, previously unrecognized controls on water and the carbon cycle in peatlands.

scholarly journals Ground penetrating radar detection of subsnow liquid overflow on ice-covered lakes in interior Alaska

2012 ◽  
Vol 6 (4) ◽  
pp. 3079-3099 ◽  
Author(s):  
A. Gusmeroli ◽  
G. Grosse
Keyword(s):  
Ground Penetrating Radar ◽  
Geophysical Methods ◽  
Arctic Region ◽  
Lake Ice ◽  
Wet Snow ◽  
Dry Conditions ◽  
Ground Penetrating ◽  
Ice Water ◽  
Safe Access

Abstract. Lakes are abundant throughout the pan-Arctic region. For many of these lakes ice cover lasts for up to two thirds of the year. This frozen cover allows human access to these lakes, which are therefore used for many subsistence and recreational activities, including water harvesting, fishing, and skiing. Safe access to these lakes may be compromised, however, when, after significant snowfall, the weight of the snow acts on the ice and causes liquid water to spill through weak spots and overflow at the snow-ice interface. Since visual detection of subsnow liquid overflow (SLO) is almost impossible our understanding on SLO processes is still very limited and geophysical methods that allow SLO detection are desirable. In this study we demonstrate that a commercially available, lightweight 1GHz, ground penetrating radar system can detect and map extent and intensity of SLO. Radar returns from wet snow-ice interfaces are at least twice as much in strength than returns from dry snow-ice interface. The presence of SLO also affects the quality of radar returns from the base of the lake ice. During dry conditions we were able to profile ice thickness of up to 1 m, conversely, we did not retrieve any ice-water returns in areas affected by SLO.

Vertical fracture detection by exploiting the polarization properties of ground‐penetrating radar signals

Geophysics ◽  
2004 ◽  
Vol 69 (3) ◽  
pp. 803-810 ◽  
Author(s):  
Georgios P. Tsoflias ◽  
Jean‐Paul Van Gestel ◽  
Paul L. Stoffa ◽  
Donald D. Blankenship ◽  
Mrinal Sen
Keyword(s):  
Ground Penetrating Radar ◽  
Field Measurements ◽  
Domain Modeling ◽  
Fracture Detection ◽  
Vertical Fracture ◽  
Phase Lead ◽  
Time Domain Modeling ◽  
Single Polarization ◽  
Ground Penetrating

Vertically oriented thin fractures are not always detected by conventional single‐polarization reflection profiling ground‐penetrating radar (GPR) techniques. We study the polarization properties of EM wavefields and suggest multipolarization acquisition surveying to detect the location and azimuth of vertically oriented fractures. We employ analytical solutions, 3D finite‐difference time‐domain modeling, and field measurements of multipolarization GPR data to investigate EM wave transmission through fractured geologic formations. For surface‐based multipolarization GPR measurements across vertical fractures, we observe a phase lead when the incident electric‐field component is oriented perpendicular to the plane of the fracture. This observation is consistent for nonmagnetic geologic environments and allows the determination of vertical fracture location and azimuth based on the presence of a phase difference and a phase lead relationship between varying polarization GPR data.

Conditional stochastic inversion of common-offset GPR reflection data

Geophysics ◽  
2021 ◽  
pp. 1-49
Author(s):  
Zhiwei Xu ◽  
James Irving ◽  
Yu Liu ◽  
Zhu Peimin ◽  
Klaus Holliger
Keyword(s):  
Ground Penetrating Radar ◽  
Synthetic Data ◽  
Field Measurements ◽  
Data Set ◽  
Stochastic Inversion ◽  
Reflection Data ◽  
Inversion Procedure ◽  
Borehole Logs ◽  
Ground Penetrating ◽  
Porosity Measurements

We present a stochastic inversion procedure for common-offset ground-penetrating radar (GPR) reflection measurements. Stochastic realizations of subsurface properties that offer an acceptable fit to GPR data are generated via simulated annealing optimization. The realizations are conditioned to borehole porosity measurements available along the GPR profile, or equivalent measurements of another petrophysical property that can be related to the dielectric permittivity, as well as to geostatistical parameters derived from the borehole logs and the processed GPR image. Validation of our inversion procedure is performed on a pertinent synthetic data set and indicates that the proposed method is capable of reliably recovering strongly heterogeneous porosity structures associated with surficial alluvial aquifers. This finding is largely corroborated through application of the methodology to field measurements from the Boise Hydrogeophysical Research Site near Boise, Idaho, USA.

scholarly journals Finite-difference time domain (FDTD) modeling of ground penetrating radar pulse energy for locating burial sites

2019 ◽  
Vol 67 (6) ◽  
pp. 1945-1953 ◽  
Author(s):  
Akinniyi Akinsunmade ◽  
Jerzy Karczewski ◽  
Ewelina Mazurkiewicz ◽  
Sylwia Tomecka-Suchoń
Keyword(s):  
Finite Difference ◽  
Time Domain ◽  
Pulse Energy ◽  
Ground Penetrating Radar ◽  
Finite Difference Time Domain ◽  
Field Measurements ◽  
Data Interpretation ◽  
Real Field ◽  
Ground Penetrating ◽  
Difference Time

Abstract Analysis of the finite-difference time domain (FDTD) numerical simulation of ground penetrating radar (GPR) measurement for locating burial sites is described in this paper. Effective, efficient, and reliability interpretation of GPR field data obtained from clandestine sites is very crucial in forensic investigations. The main goal of the study is the prediction of the change in the interaction of the electromagnetic incident on changes in buried bodies with time. In order to achieve this, the research involves the modeling of the GPR electromagnetic pulse energy responses to simulated changes in buried body with time with a view to understand what the results of real field measurement will give. The field measurements were conducted with GPR system manufactured by Mala Geoscience with antennae frequency of 500 MHz, 250 MHz, and 100 MHz. Responses from both synthetic and field radargrams depict the target was intercepted at same time (approximately 25 ns). The results have demonstrated that FDTD modeling is an important tool for enhancing the reliability of GPR data interpretation particularly for forensic study.

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