• Journal of Environmental Science International
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• v.22 no.7
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• pp.885-893
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• 2013

The purpose of this study was to analyze the effects of partial solar eclipse on 21 May 2012 in Korea on meteorological variables in Busan. 0800 LST(Local Standard Time) solar radiation was similar or lower than 0700 LST solar radiation, and sunshine duration decreased by 0.2~0.5 hours in Busan and great cities under the influence of the partial solar eclipse. Temperature drop due to the partial solar eclipse was $0.2{\sim}2.0^{\circ}C$, time taken to arrive at maximum temperature after onset of eclipse was 8~62 minutes, and time taken to arrive at minimum temperature after maximum eclipse was -9~17 minutes in Busan. Change of wind speed was negligible as partial solar eclipse occurred in the morning. Soil temperature of 5 cm was minute as well, the increase of soil temperature due to sunset was delayed by more than 1 hour.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.234-237
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• 2011

This study was carried out to investigate the effect of soil covering materials such as rice bran, rice hull and saw dust on garlic growth through a field experiment in wintertime. Rice bran was the smallest in term of particle size, but it recorded the highest level of bulk density. The missing plant rate after winter season was relatively high, 59.3%, and that of soil covering materials stood at the low level of 10%. Other growth factors recorded the highest level during application of rice bran. In terms of chemical properties of soil-covering materials, rice bran recorded the highest level of 1.84, 2.34 and 0.16% in the content of N, P, and K, respectively. The subsoil temperature was higher by application of rice bran as compared to that of other materials which stood at the lowest temperature ($-9^{\circ}C$).

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.57-70
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• 2015

This paper presents the results of an investigation into the effect of forced temperature change cycles on physical and mechanical properties of sand and weathered granite soil. The effect of forced temperature change cylecs on the particle arrangement and the thermal conductivity was first investigated. A series of triaxial compression tests on the soils were also performed to look into the effect of temperature change cycles on the stress-strain-strength behavior. The results indicated that the forced temperature change cycle does not significantly affect the particle arrangement and thermal conductivity. It is shown however that the heating duration showed some effect on the deviatoric stress at failure while no significant effect due to the number of heating-cooling cycle was observed.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.821-831
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• 2009

The study was aimed to assess the expected impact of climate change on the water cycle and soil losses in Daecheong Reservoir watershed, Korea using the Soil and Water Assessment Tool (SWAT) that was validated for the watershed in a previous study. Future climate data including precipitation, temperature and humidity generated by introducing a regional climate model (Mesoscale Model Version 5, MM5) to dynamically downscale global circulation model (European Centre Hamburg Model Version 4, ECHAM4) were used to simulate the hydrological responses and soil erosion processes in the future 100 years (2001~2100) under the Special Report on Emissions Scenario (SRES) A1B. The results indicated that the climate change may increase in the amount of surface runoff and thereby sediment load to the reservoir. Spatially, the impact was relatively more significant in the subbasin Bocheongcheon because of its lower occupation rate of forest land compared to other subbasins. Seasonally, the increase of surface runoff and soil losses was more significant during late summer and fall season when both flood control and turbidity flow control are necessary for the reservoir and downstream. The occurrence of extreme turbidity flow events during these period is more vulnerable to reservoir operation because the suspended solids that remained water column can be resuspended by vertical mixing during winter turnover period. The study results provide useful information for the development of adaptive management strategy for the reservoir to cope with the expected impact of future climate change.

• Journal of Korean Society of Rural Planning
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• v.16 no.4
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• pp.109-116
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• 2010

Climate change is known to affect both natural and managed ecosystems, and will likely impact on the terrestrail carbon balance. This paper reports the effects of climate change on spatial-temporal changes in carbon reductions in South Korea's during 2000-2100. Future carbon (C) stock distributions are simulated for the same period using various spatial data sets including land cover, net primary production(NPP) and leaf area index (LAI) obtained from MODIS(Moderate Resolution Imaging Spectroradiometer), and climate data from Data Assimilation Office(DAO) and Korea Meteorological Administration(KMA). This study attempts to predict future NPP using multiple linear regression and to model dependence of soil respiration on soil temperature. Plants store large amounts of carbon during the growing periods. During 2030-2100, Carbon accumulation in vegetation was increased to $566{\sim}610gC/m^2$/year owing to climate change. On the other hand, soil respiration is a key ecosystem process that releases carbon from the soil in the form of carbon dioxide. The estimated soil respiration spatially ranged from $49gC/m^2$/year to $231gC/m^2$/year in the year of 2010, and correlating well with the reference value. This results include Spatial-Temporal C reduction variation caused by climate change. Therefore this results is more comprehensive than previous results. The uncertainty in this study is still large, but it can be reduced if a detailed map becomes available.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.361-367
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• 2009

The criteria such as ASTM recommends that the zero reading process of CPT must be performed in the same temperature condition with underground in order to reduce the effect of temperature. However, this method can not consider the change of temperature occurred during penetration. In this study, ultra small size temperature sensor with 0.5mm in diameter is manufactured to estimate and compensate the effect of temperature by using FBG sensor. The continuous temperature changes are monitored during cone penetration by using FBG temperature sensor installed in cone penetrometer. The temperature compensated tip resistances show the uniform and similar distributions with depth in different with originally measured tip resistance in cohesive soil. This study verifies that the tip resistances measured by previous zero reading method are affected by the change of underground temperature, and suggests the new temperature compensation technique using by FBG temperature sensor.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.3
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• pp.19-28
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• 2023

The purpose of this study is to estimate carbon dioxide emissions from soil microbial respiration by forest type of Sobaeksan National Park. As a result of estimating the annual soil microbiological respiration volume by forest type in Sobaeksan National Park, broad-leaved forests, coniferous forest, artificial forests were similar to around 19.5 CO₂-ton/ha/yr. In the case of coniferous forests in sub-alpine and grassland near Birobong Peak, 12.2 CO₂-ton/ha/yr and 8.1 CO₂-ton/ha/yr, respectively, were lower than general forest areas. And as a result of analyzing the changes in soil microbiological respiration rate according to forest type in Sobaeksan National Park, the soil microbiological respiration rate in coniferous forests, broad-leaved forests, artificial forests, and sub-alpine areas was the highest in the July survey in summer and the lowest in November in late autumn. The change in soil microbial respiratory volume according to the measurement time in Sobaeksan National Park was the highest between 12:00 and 16:00, when the soil temperature was generally the highest among the days. It is known that the soil temperature is relatively low and the amount of soil microbial respiration decreases during winter, and the change in respiratory volume over the measurement time during the day was the smallest in November, when the amount of soil microbial respiration was relatively smaller than the May-September survey. However, this study has limitations in revealing the causal relationship of various environmental factors that affect the soil microbial respiration. Therefore, it is suggested that long-term research and investigation of various factors affecting soil respiration are needed to understand the carbon cycle of forest ecosystems.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.733-738
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• 2004

Recently continuous welded rail is generally used to ensure running performances and to overcome the problems such as structural vulnerability and fastener damage at the rail expansion joint. Though the use of continuous welded rail on bridge has the advantage of decreasing the vibration and damage of rail, it still the risk of buckling and breaking of rail due to change of temperature, starting and/or breaking force, axial stress concentration and so on. So, VIC code and many methods has been developed by researchers considering rail-bridge interaction. Although there are many research concerning stability of continuous welded rail about temperature change on bridge and starting and/or breaking force, the study of continuous welded mil for earthquake load is still unsufficient. In this study, the nonlinear seismic response analysis of continuous welded rail on bridge considering soil-structure interaction, geotechnical characteristic of foundation and earthquake isolation equipment has been performed to examine the stability of continuous welded rail.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.133-140
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• 2008

The growth of root and shoot normally decline dramatically in mid-summer of Korea, moreover the cool-season turfgrassgrass eventually wither to death over $30^{\circ}C$. The increase of air temperature also drives the heat of soil, that makes stress on root system. The heat stress affects physiological mechanisms of hormonal unbalance that stimulates shoot growth, photosynthesis, and transpiration. To solve those problems, many studies have been carried out to control soil moisture and OM content to decrease soil temperature for dissolving the growth retardant by heat stress. This study initiated to analyze the change of soil temperature with soil moisture, and the effect of soil depth and moisture content on heat transmit and thermal changes on turfgrass growth(productivity, green color, and damage by dryness and high temperature). Kentucky bluegrass plots prepared with 25%, 33%, 40% soil moisture treatments. Soil temperature was measured every five min. with four thermo-sensors at 12 and 2 cm soil depth. The most acceptable growth showed at 33% soil moisture, but the worst result showed at 40%. The soil moisture seriously affected on the growth of Kentucky bluegrass, however the quality of turfgrass may acceptable if we can control soil moisture down to 33% when the flooding season of monsoon.

• Asian Journal of Turfgrass Science
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• v.4 no.1
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• pp.42-48
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• 1990

Experiments were conducted to investigate the soil freezing depth and pattern with freezing measuring instruments during 1988-l989 winter season in Kangwon province. Freezing measuring instrument was made with acrylic pipes which were consisted of inner and outer parts. Inner pipe was filled with 0.01 % methylene blue solution and rubber hose to protect pipe breakdown by solution freezing. Freezing measurements were carried out by observing discoloration of methylene blue solution. Moisture content of evergreen trees and ground cover plants was also examined in the winter season. The observed results are as follows: 1.In the land of I OOM above sea level, soil freezing depth became deeper as the sum of Accumulated degree-days of temperature below 0˚C(0˚C . day) increased: Soil freezing depth was 30-40cm at l00˚C, 42-43cm at 150˚C, and 47cm at 200˚C day 2.Soil freezing with vinyl mulching was less developed by l3cm at l00˚C with sum of subzero temperature, by l7cm at 200˚C than that of the bare ground. Soil of rich hulls mulching with 4Ocm was not frozen until soil freezing at the bare ground was developed to 25cm depth. 3.Cashmeron mulching was more effective than felt mulching in the heat insulation of soil. 4.Thawing of soil was done from the lowest part of the frozen in the ground to upward in the beginning and after that it was done from the surface of frozen soil to downward. Finally thawing was completed at the middle of frozen soil.