scholarly journals Permafrost Thaw with Thermokarst Wetland-Lake and Societal-Health Risks: Dependence on Local Soil Conditions under Large-Scale Warming

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 574 ◽  
Author(s):  
Jan-Olof Selroos ◽  
Hua Cheng ◽  
Patrik Vidstrand ◽  
Georgia Destouni
Keyword(s):  
Large Scale ◽  
Mineral Soil ◽  
Soil Conditions ◽  
Lake Ecosystems ◽  
Surface Warming ◽  
Permafrost Thaw ◽  
Rock Formations ◽  
Local Soil ◽  
Local Soil Conditions ◽  
Mineral Soils

A key question for the evolution of thermokarst wetlands and lakes in Arctic and sub-Arctic permafrost regions is how large-scale warming interacts with local landscape conditions in driving permafrost thaw and its spatial variability. To answer this question, which also relates to risks for ecology, society, and health, we perform systematic model simulations of various soil-permafrost cases combined with different surface-warming trends. Results show that both the prevalence and the thaw of permafrost depended strongly on local soil conditions and varied greatly with these for the same temperature conditions at the surface. Greater ice contents and depth extents, but also greater subsurface volumes thawing at depth under warming, are found for peat soils than other studied soil/rock formations. As such, more thaw-driven regime shifts in wetland/lake ecosystems, and associated releases of previously frozen carbon and pathogens, may be expected under the same surface warming for peatlands than other soil conditions. Such risks may also increase in fast permafrost thaw in mineral soils, with only small thaw-protection effects indicated in the present simulations for possible desertification enhancement of mineral soil covers.

An experiment in the control of the ground water-level in a fen peat soil

1951 ◽  
Vol 41 (1-2) ◽  
pp. 149-162 ◽  
Author(s):  
H. H. Nicholson ◽  
G. Alderman ◽  
D. H. Firth
Keyword(s):  
Ground Water ◽  
Water Level ◽  
Large Scale ◽  
Field Experiments ◽  
Peat Soil ◽  
Climatic Conditions ◽  
Ground Water Level ◽  
Effective Control ◽  
Soil Conditions ◽  
Local Soil

1. The methods of investigation of the effect of ground water-level on crop growth, together with tho field installations in use, are discussed.2. Direct field experiments are handicapped by the difficulties of achieving close control on a sufficiently large scale, due to considerable variations of surface level and depth of peat within individual fields and to rapid fluctuations in rainfall and evaporation. Many recorded experiments are associated with climatic conditions of substantial precipitation during the growing season.3. Seasonal fluctuations of ground water-level in Fen peat soils in England, in natural and agricultural conditions, are described.4. The local soil conditions are outlined and the implications of profile variations are discussed.5. The effective control of ground water-level on a field scale requires deep and commodious ditches and frequent large underdrains to ensure the movement of water underground with sufficient freedom to give rapid compensatory adjustment for marked disturbances of ground water-level following the incidence of heavy rain or excessive evaporation.6. A working installation for a field experiment in ordinary farming conditions is described and the measure of control attained is indicated.

Modification of seismograph records for effects of local soil conditions

1972 ◽  
Vol 62 (6) ◽  
pp. 1649-1664 ◽  
Author(s):  
P. Schnabel ◽  
H. Bolton Seed ◽  
J. Lysmer
Keyword(s):  
San Francisco ◽  
Ground Surface ◽  
Soil Conditions ◽  
Local Soil ◽  
Geological Conditions ◽  
Soil Deposits ◽  
Time Histories ◽  
Seismic Records ◽  
Local Soil Conditions ◽  
Good Agreement

abstract A procedure for modifying the time histories of seismic records for the effect of local soil conditions is presented. The method is based on a conventional one-dimensional wave-propagation approach with equivalent linear soil properties, extended to practical use for transient motions through the Fast Fourier technique. The validity of the approach is tested against the motions recorded at four soil sites and one rock site during the 1957 San Francisco earthquake. The good agreement between the computed and recorded values indicates that rock motions can be computed from motions recorded on soil deposits, and that the computed rock motions in turn can be used to predict the motion that would have been recorded under different soil and geological conditions. The method is also used to evaluate the probable rock motions in the vicinity of El Centro in the earthquake of 1940 and the ground surface motions that could have been developed on various soil conditions in the same general area.

Analysis of Earthing System Cabinet of Telekom Malaysia

2015 ◽  
Vol 799-800 ◽  
pp. 1249-1256
Author(s):  
David Caulker ◽  
Mohd Annuar Ramli
Keyword(s):  
Computer Simulation ◽  
Simulation Software ◽  
Current Injection ◽  
Soil Conditions ◽  
Soil Resistivity ◽  
Specific Location ◽  
Local Soil ◽  
Local Soil Conditions ◽  
Earthing Systems ◽  
The Impact

This paper investigated the impact on the earthing systems of cabinets of Telekom Malaysia (TM) when subjected to dangerous voltages due to current injection from remote sources. TM have received numerous cases regarding the failures of their cabinets due to power related issues (PRI) as well as lightning. These failures may have occurred partly due to the existing earthing systems installations. This research aims to determine earthing impedance of 5 ohms or less of TM cabinets with respect to local soil conditions. Low impedance earthing is not easy to realize mainly due to the local soil resistivity, layering and structures. To achieve a low impedance of below 5 ohms as per Telekom Malaysia's requirement, three types of earthing electrodes were modelled and simulated using CDEGS computer simulation software. Results have demonstrated that the existing earthing system of 3 rods practice by TM is sufficient for areas of resistivity less than 500ٹ-m. Combination of rectangular and vertical rods for resistivity of 500ٹ-m above is the preferred choice of earthing. Analysis and discussions presented in this study can be used as a guide for TM for their cabinet installations. Results also highlighted that achieving less than 5ٹ does not constitute a safe earthing system. Other parameters have to be taken into account before ascertain which type of earthing to be used in a specific location of a TM installation.

Effect of soil type and depth on crop production

1984 ◽  
Vol 103 (2) ◽  
pp. 377-386 ◽  
Author(s):  
J. W. S. Reith ◽  
R. H. E. Inkson ◽  
K. S. Caldwell ◽  
W. E. Simpson ◽  
J. A. M. Ross
Keyword(s):  
Soil Type ◽  
Crop Production ◽  
Dry Matter ◽  
Soil Depth ◽  
Mineral Soil ◽  
Soil Series ◽  
Land Capability ◽  
Local Soil ◽  
Peaty Soil ◽  
Mineral Soils

SUMMARYTopsoils from eight different soil series were substituted for the local soil in three arrangements involving two depths of topsoil and either local or sand subsoils. A rotation of crops was grown with uniform annual N, P and K treatments for 24 years. A peaty soil produced the highest yields of grain, straw and grass, presumably because it released more N than the mineral soils, but an average yield of swedes. No mineral soil consistently produced higher yields of all crops and, although there were some significant differences, the variations in yield were generally relatively small. The deep topsoil consistently produced the highest yields. Topsoil with sand subsoil gave the lowest yields of grain, straw and swedes but not of grass.All the crops on the peaty soil had higher concentrations of P in the dry matter than those from the seven mineral soils. Crops and herbage on the Laurencekirk and Foud-land soils had consistently slightly higher P concentrations than those on the other five mineral soils. Compared with the amounts applied, the crops removed considerably more K but only 45–68% of the P. There were large differences in the proportion of the P residues extractable by acetic acid from the different soil series.The depth of topsoil was at least as important as soil type in determining yield, and the results support the use of soil depth as one of the main factors used in the Land Capability Classification for Agriculture.

scholarly journals Woody plants constructing tundra soils

2019 ◽  
Author(s):  
Julia Kemppinen ◽  
Pekka Niittynen ◽  
Anna-Maria Virkkala ◽  
Konsta Happonen ◽  
Henri Riihimäki ◽  
...  
Keyword(s):  
Woody Plants ◽  
Global Climate ◽  
Climatic Conditions ◽  
Soil Conditions ◽  
Observation Study ◽  
Carbon Cycles ◽  
Soil Variables ◽  
Soil Organic Carbon Stocks ◽  
Local Soil ◽  
Local Soil Conditions

AbstractIn tundra, woody plants are expanding towards higher latitudes and altitudes due to increasingly favourable climatic conditions. Their expansion may also occur through increases in the coverage and height of the plants. These shifts may cascade further across the ecosystem, such as in the foundations of tundra: that is, in the soils. Yet, little is known about the effects woody plants have on local soil conditions. Here, we examined if the coverage and height of woody plants affect the growing-season soil moisture and temperature as well as soil organic carbon stocks. We carried out a field observation study in a dwarf shrub–dominated tundra and built a hierarchical model. We found that, after controlling for other possible factors influencing woody plants and soil conditions (namely, topography, snow, and the overall plant coverage), the coverage of woody plants inversely correlated with all three soil conditions. Yet, we found no link between the woody plant height to the soil variables. This indicates that woody plants affect local soil conditions in various ways, depending upon whether their expansion occurs though the growth of coverage or their height. Nevertheless, woody plants likely alter the very ground of the entire tundra system and feedback into the global climate system through the water, energy, and carbon cycles of tundra.

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