La répartition du pergélisol dans la région du détroit de Manitounuk, côte est de la mer d'Hudson, Canada

1984 ◽  
Vol 21 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Maurice K. Seguin ◽  
Michel Allard
Keyword(s):  
Land Surface ◽  
Thermal Effects ◽  
Snow Depth ◽  
East Coast ◽  
Sea Water ◽  
Hudson Bay ◽  
Structural Elements ◽  
Mud Volcanoes ◽  
Freeze Thaw ◽  
Groundwater Movement

Forty-four AC electrical resistivity soundings have been made on the Manitounuk Islands (55°30′N, east coast of Hudson Bay) as well as in post-glacial and Recent marine sediments of the supratidal zone along the east shore of Manitounuk Strait. The results indicate that permafrost, which may have a thickness of 30 m, is present within basalts and quartzites of the cuestas at elevations above 20 m. The thermal effect of the sea and the possible infiltration of sea water in the structural elements prevent the formation of permafrost at lower altitudes. Rocky sites where permafrost has been detected are windswept areas devoid of snow. Heaved bedrock landforms are numerous on those sites. Along the east coast of Manitounuk Strait permafrost is scattered in patches and the permafrost landforms are degrading. Seasonal freeze–thaw processes are responsible for many features, such as thufurs, boulder heaving, clastic dykes, mud volcanoes, and others. The processes are related to year to year variability in the temperature regime, snow depth over the land surface, groundwater movement, thermal effects of the tides, and shore ice on the tidal flat.

scholarly journals Female reproductive biology and spawning periodicity of two species of king prawns, Penaeus longistylus Kubo and Penaeus latisulcatus Kishinouye, form Queensland's East Coast Fishery

1988 ◽  
Vol 39 (6) ◽  
pp. 729 ◽  
Author(s):  
AJ Courtney ◽  
MCL Dredge
Keyword(s):  
Egg Production ◽  
East Coast ◽  
Sea Water ◽  
Coastal Region ◽  
Ovary Development ◽  
Commercial Catch ◽  
Ovary Weight ◽  
Species Population ◽  
Spawning Periodicity ◽  
Catch Rates

In the coastal region of central Queensland female red-spot king prawns, P. longistylus, and the western or blue-leg king prawns, P. latisulcatus, had high mean ovary weights and high proportions of advanced ovary development during the winter months of July and August of 1985 and 1986. On the basis of insemination, both species began copulating at the size of 26-27 mm CL, but P. longistylus matured and spawned at a smaller size than P. latisulcatus. Abundance of P. longistylus was generally three to four times greater than that of P. latisulcatus but the latter was subject to greater variation in abundance. Low mean ovary weight and low proportions of females with advanced ovaries were associated with the maximum mean bottom sea-water temperature (28.5�C) for both species. Population fecundity indices indicated that peaks in yolk or egg production (a) displayed a similar pattern for both species, (b) varied in timing from year to year for both species and (c) were strongly influenced by abundance. Generally, sample estimates of abundance and commercial catch rates (CPUE) showed similar trends. Differences between the two may have been due to changes in targeted commercial effort in this multi-species fishery.

Hygienic Aspects of the Use of Desalinated Sea Water for Drinking and Household Purposes: A Literature Review

2021 ◽  
pp. 26-32
Author(s):  
OO Sinitsyna ◽  
VV Turbinsky ◽  
TM Ryashentseva ◽  
EP Lavrik
Keyword(s):  
Drinking Water ◽  
Fresh Water ◽  
Land Surface ◽  
Sea Water ◽  
Additional Treatment ◽  
Toxic Substances ◽  
Seawater Desalination ◽  
Preliminary Preparation ◽  
And Migration ◽  
Desalination Plants

Background. Uneven distribution of fresh water sources on the land surface encourages a search for effective techniques of potable water preparation by desalination of seawater. Hygienic issues of such desalination methods as distillation, reverse osmosis, electrodialysis, and ion exchange have been investigated by now and appropriate limitations, requirements, and additional measures to ensure safety of desalinated drinking water have been established. Objective. To summarize and systematize the results of studying characteristics of various methods of seawater desalination for its further use for drinking and household purposes. Materials and methods. We conducted a systematic review of studies published in Russian and in English, found in the PubMed and Web of Science databases, and selected 40 literary sources containing an empirical assessment of effectiveness of seawater desalination and preparation of drinking water. We also scrutinized regulatory documents and guidelines of domestic sanitary legislation. The research results were systematized by the main desalination methods. Results and discussion. We established that the use of seawater for the preparation of fresh water for drinking and household purposes is becoming increasingly widespread around the world. Drinking water obtained from seawater, in all cases, requires additional treatment and measures to optimize its mineral composition and protect against microorganisms. Conclusion. The main challenges of ensuring sanitary and epidemiological wellbeing of the population when using desalinated seawater for drinking and household purposes include selection of a source, arrangement of sites of water intake properly protected from natural and man-made pollution, substantiation of techniques and modes of preliminary preparation of source seawater adequate to its composition, basic desalination, ensuring safety of products of destruction and migration of toxic substances from reagents and materials of desalination plants, additional conditioning with the necessary elements and disinfection of the prepared water, as well as environmental protection from desalination waste.

scholarly journals Evaluation of air–soil temperature relationships simulated by land surface models during winter across the permafrost region

2016 ◽  
Vol 10 (4) ◽  
pp. 1721-1737 ◽  
Author(s):  
Wenli Wang ◽  
Annette Rinke ◽  
John C. Moore ◽  
Duoying Ji ◽  
Xuefeng Cui ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Land Surface ◽  
Snow Depth ◽  
Soil Depth ◽  
Permafrost Region ◽  
Simple Relationship ◽  
Land Surface Models ◽  
Cross Model ◽  
Near Surface ◽  
Surface Models

Abstract. A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models, and compare them with observations from 268 Russian stations. There are large cross-model differences in the simulated differences between near-surface soil and air temperatures (ΔT; 3 to 14 °C), in the sensitivity of soil-to-air temperature (0.13 to 0.96 °C °C−1), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, hence guide improvements to the model's conceptual structure and process parameterisations. Models with better performance apply multilayer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (13.19 to 15.77 million km2). However, there is not a simple relationship between the sophistication of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, because several other factors, such as soil depth used in the models, the treatment of soil organic matter content, hydrology and vegetation cover, also affect the simulated permafrost distribution.

Experimental Study On The Behavior Of Concrete Structural Elements In Natural Sea Water

1977 ◽  
Author(s):  
Jean Paul Peyronnet ◽  
Jacques Paul Trinh ◽  
M. Paul Kavyrchine ◽  
Michel Paul Seguin
Keyword(s):  
Experimental Study ◽  
Sea Water ◽  
Structural Elements

scholarly journals Subgrid snow depth coefficient of variation spanning alpine to sub-alpine mountainous terrain

2021 ◽  
Author(s):  
Graham A. Sexstone ◽  
Steven R. Fassnacht ◽  
Juan I. López-Moreno ◽  
Christopher A. Hiemstra
Keyword(s):  
Coefficient Of Variation ◽  
Land Surface ◽  
Snow Depth ◽  
Mountainous Terrain ◽  
Mountainous Regions ◽  
Scale Modeling ◽  
Roughness Elements ◽  
Wide Range ◽  
Performance Statistics ◽  
Snowpack Properties

Given the substantial variability of snow in complex mountainous terrain, a considerable challenge of coarse scale modeling applications is accurately representing the subgrid variability of snowpack properties. The snow depth coefficient of variation (CVds) is a useful metric for characterizing subgrid snow distributions but has not been well defined by a parameterization for mountainous environments. This study utilizes lidar-derived snow depth datasets spanning alpine to sub-alpine mountainous terrain in Colorado, USA to evaluate the variability of subgrid snow distributions within a grid size comparable to a 1000 m resolution common for hydrologic and land surface models. The subgrid CVds exhibited a wide range of variability across the 321 km2 study area (0.15 to 2.74) and was significantly greater in alpine areas compared to subalpine areas. Mean snow depth was the dominant driver of CVds variability in both alpine and subalpine areas, as CVds decreased nonlinearly with increasing snow depths. This negative correlation is attributed to the static size of roughness elements (topography and canopy) that strongly influence seasonal snow variability. Subgrid CVds was also strongly related to topography and forest variables; important drivers of CVds included the subgrid variability of terrain exposure to wind in alpine areas and the mean and variability of forest metrics in subalpine areas. Two statistical models were developed (alpine and subalpine) for predicting subgrid CVds that show reasonable performance statistics. The methodology presented here can be used for characterizing the variability of CVds in snow-dominated mountainous regions, and highlights the utility of using lidar-derived snow datasets for improving model representations of snow processes.

scholarly journals Forcing the SURFEX/Crocus snow model with combined hourly meteorological forecasts and gridded observations in southern Norway

2017 ◽  
Author(s):  
Hanneke Luijting ◽  
Dagrun Vikhamar-Schuler ◽  
Trygve Aspelien ◽  
Mariken Homleid
Keyword(s):  
Land Surface ◽  
Snow Depth ◽  
Water Resource Management ◽  
Snow Accumulation ◽  
Surface Model ◽  
Snow Melt ◽  
Grid Spacing ◽  
Snow Covered Area ◽  
Covered Area ◽  
Southern Norway

Abstract. In Norway, thirty percent of the annual precipitation falls as snow. Knowledge of the snow reservoir is therefore important for energy production and water resource management. The land surface model SURFEX with the detailed snowpack scheme Crocus (SURFEX/Crocus) has been run with a grid spacing of approximately 1 km over an area in southern Norway for two years (01 September 2014–31 August 2016), using two different forcing data sets: 1) hourly meteorological forecasts from the operational weather forecast model AROME MetCoOp (2.5 km grid spacing), and 2) gridded hourly observations of temperature and precipitation (1 km grid spacing) in combination with the meteorological forecasts from AROME MetCoOp. We present an evaluation of the modeled snow depth and snow cover, as compared to point observations of snow depth and to MODIS satellite images of the snow-covered area. The evaluation focuses on snow accumulation and snow melt. The results are promising. Both experiments are capable of simulating the snow pack over the two winter seasons, but there is an overestimation of snow depth when using only meteorological forecasts from AROME MetCoOp, although the snow-covered area throughout the melt season is better represented by this experiment. The errors, when using AROME MetCoOp as forcing, accumulate over the snow season, showing that assimilation of snow depth observations into SURFEX/Crocus might be necessary when using only meteorological forecasts as forcing. When using gridded observations, the simulation of snow depth is significantly improved, which shows that using a combination of gridded observations and meteorological forecasts to force a snowpack model is very useful and can give better results than only using meteorological forecasts. There is however an underestimation of snow ablation in both experiments. This is mainly due to the absence of wind-induced erosion of snow in the SURFEX/Crocus model, underestimated snow melt and biases in the forcing data.

Explorations on the East Coast of Hudson Bay

1947 ◽  
Vol 109 (1/3) ◽  
pp. 58 ◽  
Author(s):  
T. H. Manning
Keyword(s):  
East Coast ◽  
Hudson Bay

Miniature mud volcanoes and other injection features in tidal flats, James Bay, Québec

1976 ◽  
Vol 13 (3) ◽  
pp. 422-428 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
East Coast ◽  
Fine Sand ◽  
Tidal Flats ◽  
Mud Volcanoes ◽  
James Bay ◽  
Marine Clay ◽  
Ice Floes ◽  
Mud Deposit

Miniature injection features, including mud volcanoes, dikes forming polygonal patterns, and isolated patches of clay, occur in tidal flats along the east coast of James Bay. They are formed by localized upward ejection of a mixture of fluidized marine clay, silt, and fine sand through a surficial recent mud deposit. Liquefaction is related to the melting of ice in the clayey deposit. Upward flowing of clay, silt, and fine sand seems to result from overloading by the overlying sediments having a higher degree of density, and possibly also by pressures of ice floes or/and icefoot.

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