Application of multivariate storage model to quantify trends in seasonally frozen soil

AbstractThis article presents a study of the ground thermal regime recorded at 11 stations in the North Dakota Agricultural Network. Particular focus is placed on detecting trends in the annual ground freeze process portion of the ground thermal regime’s daily temperature signature. A multivariate storage model from queuing theory is fit to a quantity of estimated daily depths of frozen soil. Statistical inference on a trend parameter is obtained by minimizing a weighted sum of squares of a sequence of daily one-step-ahead predictions. Standard errors for the trend estimates are presented. It is shown that the daily quantity of frozen ground experienced at these 11 sites exhibited a negative trend over the observation period.

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Permafrost and thermal interfaces from Normal Wells pipeline ditchwall logs

Canadian Geotechnical Journal ◽

10.1139/t91-088 ◽

1991 ◽

Vol 28 (5) ◽

pp. 738-745 ◽

Cited By ~ 6

Author(s):

J. F. Derick Nixon ◽

R. Saunders ◽

J. Smith

Keyword(s):

Color Change ◽

Input Parameter ◽

Data File ◽

Frozen Soil ◽

The Arctic ◽

Frozen Ground ◽

The North ◽

Discontinuous Permafrost ◽

Geophysical Surveys ◽

Thermal Interfaces

During the construction of the Normal Wells pipeline by Interprovincial Pipeline Ltd. in the early 1980s, a continuous ditchwall log was created during ditching for pipeline burial. The ditch was typically 1.2 m deep and stretched continuously from Normal Wells in the Canadian Arctic to Zama Lake in northern Alberta, a total distance of 869 km through the discontinuous permafrost zone. The ditch was logged by experienced geotechnical field personnel every 50–100 m, depending on changing conditions. Every transition from unfrozen to frozen soil was logged based on visual criteria such as color change, visual presence of ice or moisture in the ditchwall, etc. Recently, the authors have carefully studied the ditchwall records and compiled a data file containing all of the relevant data pertaining to permafrost distribution. This provided a unique opportunity to study the amount and distribution of permafrost along a continuous transect through discontinuous and sporadic permafrost regions in Arctic Canada. The number of thermal interfaces per kilometre is an extremely important input parameter for studies relating to pipeline frost heave and thaw settlement in the Arctic. In addition, a knowledge of the percentage of frozen ground is important when deciding whether to operate a gas or pipeline above or below freezing. The number of frozen–unfrozen interfaces have been summarized in the paper by pipeline spread and geological terrain unit. The overall percentage of frozen ground decreases from up to 95% in the north to a low of around 16% at the south end of the study area, as might be expected. The number of interfaces typically varies between about one and three per kilometre, with the highest number occurring in some of the organic terrain units in the southern discontinuous zone. Finally, comparisons are made with the amount of permafrost and number of interfaces as logged by electrical geophysical surveys carried out and published in advance of pipeline construction. There is reasonable agreement in terms of the overall amount of frozen ground; however, the geophysical surveys may have overestimated the number of thermal interfaces in some areas. Key words: ditch logs, permafrost, Normal Wells, pipeline, thermal interfaces, frozen ground.

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MONITORING THE DYNAMICS OF THERMOABRASION COASTS AT KHARASAVEY AREA, WESTERN YAMAL (KARA SEA)

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b93ffdcdfd1.86932804 ◽

2017 ◽

Author(s):

Dmitry Kuznetsov ◽

Anatoliy Kamalov ◽

Nataliya Belova ◽

...

Keyword(s):

Human Impact ◽

Remote Sensing Data ◽

Kara Sea ◽

Motor Vehicles ◽

Yamal Peninsula ◽

Western Coast ◽

Frozen Ground ◽

Coastal Dynamics ◽

The North ◽

Ice Content

The dynamics of thermoabrasion coasts on loose sediments under permafrost conditions are highly variable due to several factors: length of the dynamic period of the year, mechanic composition of the frozen ground and its ice content, hydrometeorological conditions, and human impact. Multiannual monitoring of the coastal zone was carried out by Lab. Geoecology of the North (Moscow State University) at the 22 km long Kharasavey deposit site, Western Coast of Yamal Peninsula (Kara Sea). The methods include direct measurements and observations (repeated topographic survey of shore transects from 1981 to 2012) along with remote sensing data analysis (images from 1964 to 2011). This allowed producing detailed characteristics of coastal dynamics. At the site, thermoabrasion coasts occupy the most part, and accumulative coasts are present in the north. Data on natural relief forming factors and ground composition are included in the detailed geomorphologic map of the site. Shore retreat rate shows correlation to amounts of wind-wave energy and to specific wind directions. Human impact on the coast includes dredging at the port channel, mining of sand, driving motor vehicles, and deposition of construction debris. Relations between shore retreat rate and aforementioned factors were studied, including dependencies on ice content, and shore segmentation was carried out. This allows for coastal dynamics forecasts in the region.

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Effects of preferential flow on snowmelt partitioning and groundwater recharge in frozen soils

Hydrology and Earth System Sciences ◽

10.5194/hess-23-5017-2019 ◽

2019 ◽

Vol 23 (12) ◽

pp. 5017-5031 ◽

Cited By ~ 4

Author(s):

Aaron A. Mohammed ◽

Igor Pavlovskii ◽

Edwin E. Cey ◽

Masaki Hayashi

Keyword(s):

Soil Moisture ◽

Groundwater Recharge ◽

Preferential Flow ◽

Frozen Soil ◽

Time Lags ◽

Runoff Generation ◽

Frozen Ground ◽

Soil Matrix ◽

Frozen Soils ◽

Flow Through

Abstract. Snowmelt is a major source of groundwater recharge in cold regions. Throughout many landscapes snowmelt occurs when the ground is still frozen; thus frozen soil processes play an important role in snowmelt routing, and, by extension, the timing and magnitude of recharge. This study investigated the vadose zone dynamics governing snowmelt infiltration and groundwater recharge at three grassland sites in the Canadian Prairies over the winter and spring of 2017. The region is characterized by numerous topographic depressions where the ponding of snowmelt runoff results in focused infiltration and recharge. Water balance estimates showed infiltration was the dominant sink (35 %–85 %) of snowmelt under uplands (i.e. areas outside of depressions), even when the ground was frozen, with soil moisture responses indicating flow through the frozen layer. The refreezing of infiltrated meltwater during winter melt events enhanced runoff generation in subsequent melt events. At one site, time lags of up to 3 d between snow cover depletion on uplands and ponding in depressions demonstrated the role of a shallow subsurface transmission pathway or interflow through frozen soil in routing snowmelt from uplands to depressions. At all sites, depression-focused infiltration and recharge began before complete ground thaw and a significant portion (45 %–100 %) occurred while the ground was partially frozen. Relatively rapid infiltration rates and non-sequential soil moisture and groundwater responses, observed prior to ground thaw, indicated preferential flow through frozen soils. The preferential flow dynamics are attributed to macropore networks within the grassland soils, which allow infiltrated meltwater to bypass portions of the frozen soil matrix and facilitate both the lateral transport of meltwater between topographic positions and groundwater recharge through frozen ground. Both of these flow paths may facilitate preferential mass transport to groundwater.

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Geothermal modeling of soil or mine tailings with concurrent freezing and deposition

Canadian Geotechnical Journal ◽

10.1139/t97-081 ◽

1998 ◽

Vol 35 (2) ◽

pp. 234-250 ◽

Cited By ~ 3

Author(s):

JF (Derick) Nixon ◽

Nick Holl

Keyword(s):

Snow Cover ◽

Mine Tailings ◽

Frozen Soil ◽

Freezing And Thawing ◽

Frozen Ground ◽

Geothermal Model ◽

Winter Time ◽

Upper Boundary ◽

Good Agreement

A geothermal model is described that simulates simultaneous deposition, freezing, and thawing of mine tailings or sequentially placed layers of embankment soil. When layers of soil or mine tailings are placed during winter subfreezing conditions, frozen layers are formed in the soil profile that may persist with time. The following summer, warmer soil placement may not be sufficient to thaw out layers from the preceding winter. Remnant frozen soil layers may persist for many years or decades. The analysis is unique, as it involves a moving upper boundary and different surface snow cover functions applied in winter time. The model is calibrated based on two uranium mines in northern Saskatchewan. The Rabbit Lake scenario involves tailings growth to a height of 120 m over a period of 24 years. At Key Lake, tailings increase in height at a rate of 1.3 m/year. Good agreement between the observed position of frozen layers and those predicted by the model is obtained. Long-term predictions indicate that from 80 to 200 years would be required to thaw out the frozen layers formed during placement, assuming 1992 placement conditions continue. Deposition rates of 1.5-3 m/year give the largest amounts of frozen ground. The amount of frozen ground is sensitive to the assumed snow cover function during winter.Key words: geothermal, model, tailings, freezing, deposition.

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A Cytotoxic Porphyrin from North Pacific Brittle Star Ophiura sarsii

Marine Drugs ◽

10.3390/md19010011 ◽

2020 ◽

Vol 19 (1) ◽

pp. 11

Author(s):

Antonina Klimenko ◽

Robin Huber ◽

Laurence Marcourt ◽

Estelle Chardonnens ◽

Alexey Koval ◽

...

Keyword(s):

North Pacific ◽

Ethanol Extract ◽

2D Nmr ◽

Brittle Star ◽

Inert Material ◽

Cancer Therapies ◽

The North ◽

Anti Cancer ◽

One Step ◽

The North Pacific

Triple-negative breast cancer (TNBC) represents the deadliest form of gynecological tumors currently lacking targeted therapies. The ethanol extract of the North Pacific brittle star Ophiura sarsii presented promising anti-TNBC activities. After elimination of the inert material, the active extract was submitted to a bioguided isolation approach using high-resolution semipreparative HPLC-UV, resulting in one-step isolation of an unusual porphyrin derivative possessing strong cytotoxic activity. HRMS and 2D NMR resulted in the structure elucidation of the compound as (3S,4S)-14-Ethyl-9-(hydroxymethyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid. Never identified before in Ophiuroidea, porphyrins have found broad applications as photosensitizers in the anticancer photodynamic therapy. The simple isolation of a cytotoxic porphyrin from an abundant brittle star species we describe here may pave the way for novel natural-based developments of targeted anti-cancer therapies.

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Impact of seasonally frozen soil on germinability and antioxidant enzyme activity of Picea asperata seeds

Canadian Journal of Forest Research ◽

10.1139/x09-001 ◽

2009 ◽

Vol 39 (4) ◽

pp. 723-730 ◽

Cited By ~ 3

Author(s):

Jihong Qin ◽

Qing Liu

Keyword(s):

Oxidative Stress ◽

Antioxidant Defense ◽

Germination Rate ◽

Antioxidant Defense System ◽

Antioxidant Enzyme Activity ◽

Frozen Soil ◽

Defense System ◽

Frozen Ground ◽

Subalpine Zone ◽

Picea Asperata

In the subalpine zone of the Qinghai–Tibetan Plateau of China, Dragon spruce (Picea asperata Mast.) is commonly used for reforestation. The aim of the present work was to study the effects of seasonally frozen soil on the germination of P. asperata seeds and to investigate whether these effects were associated with resumption of the antioxidant defense system. The nonfrozen treatment resulted in near failure of germination (1%) and was associated with relatively high levels of hydrogen peroxide (H2O2) and low activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxide (APX). Germination of P. asperata seeds at 10 cm under the seasonally frozen soil was higher than that at 5 cm by 26%; this higher germination rate was associated with the recovery of SOD, CAT, and APX activities. The levels of malondialdehyde (MDA) in seeds from seasonally frozen treatments were higher than those in the nonfrozen treatment, implying greater lipid peroxidation and that frozen seeds might have suffered from oxidative stress. The results indicate that seasonally frozen soil facilitated the germination of P. asperata seeds and that germination was closely related to the resumption of antioxidant enzymes activity. Overall, these findings suggest that the disappearance of seasonally frozen ground caused by global warming might result in failure of regeneration of P. asperata.

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Finite Element Analysis of Artificially Frozen C-Phi soil

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d7264.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 12722-12728

Keyword(s):

Finite Element ◽

Numerical Analysis ◽

Frozen Soil ◽

Experimental Results ◽

Soil Freezing ◽

Strength Parameter ◽

Frozen Ground ◽

Element Analysis ◽

Test Setup ◽

Geological Conditions

Artificial Ground Freezing techniques eliminate the need for structural supports during the course of an excavation, as frozen ground is solid and waterproof. At present, it is adopted as an effective way to deal with various construction ground control challenges such as the mitigation of seepage infiltration into tunnels and shaft excavations; or ground strengthening for excavation. In-depth knowledge of the frozen soil characteristics through experiments and the development of suitable constitutive models that suit the geological conditions of our country are necessary to predict the strength and behavior of the frozen soils. Numerical analysis of frozen soil can be used for mass works like tunneling which cannot be experimentally verified. This paper presents a validation of experimental results obtained from laboratory setup and soil freezing system for C-Phi soil. The main aim is to compare numerical and experimental results and hence obtaining the shear strength parameter of the soil, similar to the conventional triaxial test setup. To perform numerical analysis Finite element tool ANSYS 19 is used. Soil model is made in ANSYS 19 and required loads are inputted to performed the analysis similar to the experimental method. The result obtained from experimental test setup and numerical analysis was verified and compared and it was found that values of numerical results lies closer to experimental results

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