ON THE POROSITY OF THE UNCONSOLIDATED PART OF ICE RIDGE KEEL

2021 ◽  
pp. 101-108
Author(s):  
V. V. Kharitonov ◽  
Keyword(s):  
Cross Section ◽  
Point Cloud ◽  
Granular Media ◽  
Penetration Rate ◽  
Arctic Basin ◽  
First Year ◽  
Average Porosity ◽  
Thermal Drilling ◽  
Severnaya Zemlya ◽  
Porosity Changes

The paper discusses the distribution of porosity of the unconsolidated part of the keel of ten first-year ice ridges investigated in the central Arctic basin and the Shokalsky Strait (Severnaya Zemlya) in 2012–2019. These studies were performed using thermal drilling with the computer (logger) recording of penetration rate. Boreholes were drilled along the cross-section of the ridge crest, mainly at 0.25-m intervals. The porosity values for the unconsolidated part of the keel are presented on the diagram as a point cloud. The horizontal position of the points is determined by the relative distance between the borehole and the point where the keel has the maximum draft. As moving away from this point, the average porosity of the unconsolidated part of the keel tends to increase. This feature is a consequence of the Archimedes force effect and agrees with the model of porosity changes from the theory of granular media.

Ice ridges in landfast ice of Shokal'skogo Strait

2019 ◽  
Vol 12 (3) ◽  
pp. 16-26
Author(s):  
Victor V. Kharitonov
Keyword(s):  
Penetration Rate ◽  
Hot Water ◽  
First Year ◽  
Height Ratio ◽  
Long Distance ◽  
Cross Sectional ◽  
Landfast Ice ◽  
Thermal Drilling ◽  
Severnaya Zemlya ◽  
Severnaya Zemlya Archipelago

Three first-year ice ridges have been examined with respect to geometry and morphology in landfast ice of Shokal'skogo Strait (Severnaya Zemlya Archipelago) in May 2018. Two of the studied ice ridges were located on the edge of the ridged field and were part of it, because their keels extended for a long distance deep into this field. Ice ridges characteristics are discussed in the paper. These studies were conducted using hot water thermal drilling with computer recording of the penetration rate. Boreholes were drilled along the cross-section of the ridge crest at 0.25 m intervals. Cross-sectional profiles of ice ridges are illustrated. The maximal sail height varied from 2.9 up to 3.2 m, the maximal keel depth varied from 8.5 up to 9.6 m. The average keel depth to sail height ratio varied from 2.8 to 3.3, and the thickness of the consolidated layer was 2.5-3.5 m. The porosity of the non-consolidated part of the keel was about 23-27%. The distributions of porosity versus depth for all ice ridges are presented.

scholarly journals Investigation of spatiotemporal variability of melt pond fraction and its relationship with sea ice extent during 2000–2017 using a new data

2019 ◽  
Author(s):  
Yifan Ding ◽  
Xiao Cheng ◽  
Jiping Liu ◽  
Fengming Hui ◽  
Zhenzhan Wang
Keyword(s):  
Sea Ice ◽  
Arctic Basin ◽  
Beaufort Sea ◽  
Arctic Sea Ice ◽  
Spatiotemporal Variability ◽  
First Year ◽  
Spatial And Temporal Variability ◽  
Sea Ice Extent ◽  
Melt Pond ◽  
Melt Ponds

Abstract. The accurate knowledge of variations of melt ponds is important for understanding Arctic energy budget due to its albedo-transmittance-melt feedback. In this study, we develop and validate a new method for retrieving melt pond fraction (MPF) from the MODIS surface reflectance. We construct an ensemble-based deep neural network and use in-situ observations of MPF from multi-sources to train the network. The results show that our derived MPF is in good agreement with the observations, and relatively outperforms the MPF retrieved by University of Hamburg. Built on this, we create a new MPF data from 2000 to 2017 (the longest data in our knowledge), and analyze the spatial and temporal variability of MPF. It is found that the MPF has significant increasing trends from late July to early September, which is largely contributed by the MPF over the first-year sea ice. The analysis based on our MPF during 2000–2017 confirms that the integrated MPF to late June does promise to improve the prediction skill of seasonal Arctic sea ice minimum. However, our MPF data shows concentrated significant correlations first appear in a band, extending from the eastern Beaufort Sea, through the central Arctic, to the northern East Siberian and Laptev Seas in early-mid June, and then shifts towards large areas of the Beaufort Sea, Canadian Arctic, the northern Greenland Sea and the central Arctic basin.

scholarly journals Glaciochemical reconnaissance of a new ice core from Severnaya Zemlya, Eurasian Arctic

2005 ◽  
Vol 51 (172) ◽  
pp. 64-74 ◽  
Author(s):  
Karin Weiler ◽  
Hubertus Fischer ◽  
Diedrich Fritzsche ◽  
Urs Ruth ◽  
Frank Wilhelms ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ice Core ◽  
Arctic Basin ◽  
Anthropogenic Pollution ◽  
The Arctic ◽  
Ice Cap ◽  
Siberian Arctic ◽  
Nitrate Concentrations ◽  
Severnaya Zemlya ◽  
Combustion Processes

AbstractA deep ice core has been drilled on Akademii Nauk ice cap, Severnaya Zemlya, Eurasian Arctic. High-resolution chemical analysis has been carried out for the upper 53 m of this ice core to study its potential as an atmospheric aerosol archive, despite strong meltwater percolation. These records show that a seasonal atmospheric signal cannot be deduced. However, strong year-to-year variations have allowed the core to be dated, and a mean annual net mass balance of 0.46 m w.e. a-1 was deduced. The chemical signature of an extraordinarily high peak in electrical conductivity at 26 m depth pointed clearly to the eruption of Bezymianny, Kamchatka, in 1956. However, in general, peaks in the electrical conductivity are not necessarily related to deposition of volcanogenic sulphur aerosol. In contrast, maximum sulphate and nitrate concentrations in the ice could be related to maximum SO2 and NOx anthropogenic emissions in the 1970s, probably caused by the nickel- and copper-producing industries in Norilsk and on the Kola peninsula or by industrial combustion processes occurring in the Siberian Arctic. In addition, during recent decades sulphate and nitrate concentrations declined by 80% and 60%, respectively, reflecting a decrease in anthropogenic pollution of the Arctic basin.

Converting Point Cloud to Revolved Solids

2013 ◽  
Vol 371 ◽  
pp. 468-472
Author(s):  
Mircea Viorel Drăgoi ◽  
Slobodan Navalušić
Keyword(s):  
Reverse Engineering ◽  
Cross Section ◽  
Software Package ◽  
Point Cloud ◽  
3D Model ◽  
Point Clouds ◽  
3D Scanning ◽  
Main Drawback ◽  
Mass Properties

3D scanning is one of the basic methods to gather data for reverse engineering. The main drawback of 3D scanning is that its output - the point cloud - can never be used directly to define surfaces or solids useful to reconstruct the electronic 3D model of the scanned part.The paper presents a piece of software designed in VisualLISP for AutoCAD, software that acts as a point cloud to 3D primitives converter. The novelty consists of the method used to find the parameters of the primitive that best fits to the point cloud: the mass properties of regions are used to find the center of a cones cross section. Parts have been scanned and the point clouds processed. The results obtained prove the correctness of the algorithm and of the method applied. A piece of software that processes the point cloud in order to find the 3D primitive that it fits the best has been developed. The output is the 3D primitive that successfully and accurate replaces the point cloud. Some adjacent tools were designed, so the entire software package becomes a useful tool for the reverse engineering user. The ways the researches can be continued and developed are foreseen, as well

scholarly journals Analysis of the joint application results of a borehole jack and thermal drilling in ice research

2018 ◽  
Vol 64 (2) ◽  
pp. 157-169
Author(s):  
V. V. Kharitonov ◽  
A. I. Shushlebin
Keyword(s):  
Penetration Rate ◽  
Ice Cover ◽  
Strength Properties ◽  
Drilling Equipment ◽  
Joint Application ◽  
Local Strength ◽  
Rate Versus ◽  
Thermal Drilling ◽  
Ice Strength ◽  
Comparison Of The Results

In last two decade, studies of ice ridge morphometry and strength properties have been actively carried out. Thermal drilling of ice and experiments to determine the local strength of ice using a borehole jack are performed. The paper discusses the issues of joint use of thermal drilling equipment and borehole jack for the ice cover research. Two approaches to the comparison of the results obtained by these two methods are considered. Average penetration rate versus local ice strength dependences are presented. With increasing ice strength and decreasing penetration rate the interval of changes in the ice strength increases and correspondence of the strength to the penetration rate decreases. Based on the results of ice ridges research, depth-wise distributions of local strength and thermal drill penetration rate are compared. Difference between the average thicknesses of the consolidated layer obtained from these distributions was 5 %.

scholarly journals Application of Laser Scanning for Creating Geological Documentation

2018 ◽  
Vol 35 ◽  
pp. 04001
Author(s):  
Michał Buczek ◽  
Martyna Paszek ◽  
Anna Szafarczyk
Keyword(s):  
Cross Section ◽  
Point Cloud ◽  
Laser Scanning ◽  
Geophysical Methods ◽  
Open Pit ◽  
Coal Bed ◽  
Hard Coal ◽  
Test Field ◽  
Geological Cross Section ◽  
Single Station

A geological documentation is based on the analyses obtained from boreholes, geological exposures, and geophysical methods. It consists of text and graphic documents, containing drilling sections, vertical crosssections through the deposit and various types of maps. The surveying methods (such as LIDAR) can be applied in measurements of exposed rock layers, presented in appendices to the geological documentation. The laser scanning allows obtaining a complete profile of exposed surfaces in a short time and with a millimeter accuracy. The possibility of verifying the existing geological cross-section with laser scanning was tested on the example of the AGH experimental mine. The test field is built of different lithological rocks. Scans were taken from a single station, under favorable measuring conditions. The analysis of the signal intensity allowed to divide point cloud into separate geological layers. The results were compared with the geological profiles of the measured object. The same approach was applied to the data from the Vietnamese hard coal open pit mine Coc Sau. The thickness of exposed coal bed deposits and gangue layers were determined from the obtained data (point cloud) in combination with the photographs. The results were compared with the geological cross-section.

scholarly journals The nature of regional magnetic anomalies in the northeast of the Barents-Kara continental margin based on the results of seismic data interpretation

2021 ◽  
Vol 11 (2) ◽  
pp. 195-204
Author(s):  
E.V. Shipilov ◽  
◽  
L.I. Lobkovsky ◽  
S.I. Shkarubo ◽  
◽  
...  
Keyword(s):  
Arctic Basin ◽  
Data Interpretation ◽  
Magnetic Anomalies ◽  
The Arctic ◽  
The North ◽  
Franz Josef Land ◽  
Seismic Reflection Method ◽  
Anna Trough ◽  
Seismic Sections ◽  
Severnaya Zemlya

Based on the interpretation of seismic sections via seismic reflection method, the lines of which intersect the positive magnetic anomalies in the St. Anna Trough and on the North Kara Shelf, the authors have substantiated the position of the Early Cretaceous dike belt in the north of the Barents-Kara platform for the first time. They traced the belt from the arch-block elevation of arch. Franz Josef Land, which belongs to the Svalbard platе through the Saint Anna Trough and further into the Kara platе to arch. Severnaya Zemlya. The distinguished dyke belt has discordant relationships with the structural-tectonic plan of the region under consideration. The authors illustrate the manifestations of dyke magmatism in the marked tectonic elements in seismic sections, and conclude that the dyke belt relates to the formation of the structural system of the Arctic basin.

scholarly journals The Optical Properties of Ice and Snow in the Arctic Basin

1977 ◽  
Vol 18 (80) ◽  
pp. 445-463 ◽  
Author(s):  
Thomas C. Grenfell ◽  
Gary A. Maykut
Keyword(s):  
Extinction Coefficient ◽  
Light Transmission ◽  
Simple Procedure ◽  
Arctic Basin ◽  
The Arctic ◽  
First Year ◽  
Flux Divergence ◽  
Near Surface ◽  
Extinction Coefficients ◽  
Melt Ponds

AbstractMeasurements of light transmission and reflection were carried out on first-year sea ice near Point Barrow, Alaska, and on multi-year ice near Fletcher’s Ice Island in the Beaufort Sea (lat. 84° N., long. 77°W.). Spectral albedos (400-1 000 nm) and extinction coefficients (400-800 nm) were determined for melt ponds, snow, and various types of bare ice. Albedos were largest in the 400-600 nm range, decreasing toward longer wavelengths at a rate which appeared to be related to the liquid-water content of the near-surface layers. Extinction coefficients remained nearly constant between 400 and 550 nm, but increased rapidly above 600 nm. At 500 nm, albedos ranged from 0.25 over mature melt ponds to 0.93 over dense dry snow, while the corresponding extinction coefficients ranged from 0.6 to 16 m-1. Intensity profiles taken in the upper 50 cm of the ice indicated that the extinction coefficient at a particular wavelength was nearly constant with depth below 15 cm, although the bulk extinction coefficient decreased with depth because of the strong attenuation in the red. Near the surface it was found that multi-year ice absorbed slightly more energy than did first-year blue ice, but at depths below 10 cm the flux divergence in the first-year ice was three to four times larger than that in the multi-year ice. A simple procedure is described for estimating light transmission and absorption within the ice under clear or cloudy skies from total flux measurements at the surface. Methods by which satellite data could be used to estimate regional albedos, melt-pond fraction, and lead area are also presented.

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