• Journal of Climate Change Research
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• v.6 no.2
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• pp.87-94
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• 2015

To compare changes in winter temperature over South Korea, 30-year average climate data and climate data of recent 10 years (2014~2014) such as mean temperature, daily maximum temperature and daily minimum temperature were analyzed. Also, we set analysis extreme cold waves frequency related to winter such as freezing days, snow days, days with temperature of below -5, and days with temperature of below -10. This process enabled the comparative analysis of winter temperature changes and extreme cold waves frequency related to winter. This study estimated that winter temperature has gradually increased throughout the last five decades, however, the frequency of extreme weather, such as cold waves has also increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.5-6
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• 2015

Recently, freezing index of frost penetration depth estimation used in Korea is applied according to the standard, published by MOLIT in 2003. However, it is difficult to consider can not be determined to standard reflects weather conditions in accordance with the current climate warming or abnormally high temperature. Also the temperature should be considered local variables because heavy local gap. Therefore, this study is through the freezing index presented in MOLIT's code by calculating the frost penetration depth determining whether the adequacy and conducted a study to apply in the field. As a result, when the Elevation 100m to standard in Incheon frost penetration depth is found to be 50.8cm.

• Geomechanics and Engineering
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• v.29 no.3
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• pp.349-357
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• 2022

Abnormal climate events are occurring frequently around the world. In particular, cold waves and heavy snow lead to damage and deterioration of facilities, which can cause loss of life or property damage, such as shortening the lifespan of facilities. Therefore, it is very important to prepare an appropriate maintenance system and to establish a strategy to cope with abnormal weather conditions. In this study, laboratory freezing experiments were performed to analyze the freeze-thaw characteristics affecting the tunnel concrete lining, and heat flow analysis was carried out based on the test results. Based on these experimental and theoretical analysis results, quantitative freeze-thaw evaluation criteria for tunnel concrete linings were proposed.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.329-334
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• 2001

Many of past studies using physically based numerical climate models indicate that increases in atmospheric $CO_2$could enhance summer dryness over continental region in middle-high latitudes. However the models used in those studies do not take account of permafrost in high latitudes. We have carried out a set of experiments applying a version of global climate model that can reproduce realistic distribution of the permafrost. From the results, it is indicated that permafrost functions as a large reservoir in hydrologic cycle maintaining dry, hot summer over continents in northern middle-high latitudes, and that the $CO_2$warming would reduce this function by causing climatological thawing of permafrost, which would result in moister and cooler summer, and warmer winter in the same region. The present study indicates that an inclusion of very simple description of soil freezing process can make a large difference in a model simulation.

• Geotechnical Engineering
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• v.5 no.4
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• pp.5-16
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• 1989

This paper statistically analyses the freezing soil by frost group and frost depth in Korea with data from soil testing in the Korea National Housing Corporation, the climate data provided by the Central Weather Office and the data on the frost depth from the National Construction Laboratory Institute. In this paper, freezing variable are analysed such as percentage finer than 0.02 m by weight, plasticity index, freezing index, water contents of soil and frost depth etc‥‥ The result of the analysis is as follows. 1) The frost depth of Korea depends on the properties of soil rather thank the characte fistic of area. 2) The distribution map of design freezing index in 57 cities is drawn up with the maxi- mum freezing index, during past 14 years, calculated by the average of the air temperature observed four times(03 : 00.09 00, 15 : 00, 21 : 00) a day. 3) By correcting the OLS line estimated from the relationship between freezing index and frost depth, a method of utlizing the line with the upper confidence limit of 99.9% int-distribution as predicted maximum frost depth is newly introduced.

• Atmosphere
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• v.25 no.2
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• pp.205-219
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• 2015

In this study, the simulation results of temperature by regional climate model (Reg- CM4) over South Korea were corrected by Hempel et al. (2013)'s method (Hempel method), and evaluated with the observation data of 50 stations from Korea Meteorological Administration. Among the 30 years (1981~2010) of simulation data, 20 years (1981~2000) of simulation data were used as a training data, and the remnant 10 years (2001~2010) data were used for the evaluation of correction. In general, the Hempel method and parametric quantile mapping show a reasonable correction both in mean and extreme climate of temperature. As the results, the systematic underestimation of mean temperature was greatly reduced after bias correction by Hempel method. And the overestimation of extreme climate, such as the number of TN5% and freezing day, was significantly recovered. In addition to that, the Hempel method better preserved the temporal trend of simulated temperature than other bias correction methods, such as the quantile mapping. However, the overcorrection of the extreme climate related to the upper quantile, such as TX5% and hot days, resulted in the exaggeration of the simulation errors. In general, the Hempel method can reduce the systematic biases embedded in the simulation results preserving the temporal trend but it tends to overcorrect the non-linear biases, in particular, extreme climate related to the upper percentile.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.213-220
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• 2009

In order to predict the risk of freeze injury for 'Changhowon Hwangdo' peach trees, we used the dormancy depth (i.e., the daily chill unit accumulation during the overwintering period) as a proxy for the short-term, physiological tolerance to freezing temperatures. A Chill-days model was employed and its parameters such as base temperature and chilling requirement were optimized for peach trees based on the 12 observational experiments during the 2008-2009 winter. The model predicted the flowering dates much closer to the observations than other models without considering dormancy depth, showing the strength of employing dormancy depth into consideration. To derive empirical equations for calculating the probabilistic freeze risk, the dormancy depth was then combined with the browning ratio and the budburst ratio of frozen peach fruit branches. Given the exact date and the predicted minimum temperature, the equations calculate the probability of freeze damages such as a failure in budburst or tissue browning. This method of employing dormancy depth in addition to freezing temperature would be useful in locating in advance the risky areas of freezing injury for peach trees production under the projected climate change.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.77-96
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• 2017

This study was carried out to clarify the climatic factors of the freezing injury for the judgement on the adaptation areas of evergreen broad-leaved trees. We surveyed and analyzed the climatic factors of the freezing injury to Machilus thunbergii Siebold & Zucc. on the streets with the analyzation of planting grounds, soil conditions and the surrounding buildings. This study showed that only the minimum air temperature factor out of the other climate elements, which were the annual precipitation; the average annual temperature; the average monthly temperature of january; the average monthly minimum temperature of January; the average temperature of the coldest month; the warmth index and the coldness index, was matched up with the previous theories and reports on the freezing damages on the evergreen broad leaved trees and Machilus thunbergii Siebold & Zucc. The freezing injury of Machilus thunbergii Siebold & Zucc was occurred when the mean minimum temperature of the coldest month(TMC) in winter season fell down below $-4.1^{\circ}C$ and the temperature fell down below $-9.2^{\circ}C$. The freezing damage on Machilus thunbergii Siebold & Zucc surrounded by high buildings were less than those surrounded by low buildings or at non buildings.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.555-559
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• 1993

Studies at freezing point depression (FPD) for goat milk are described in this paper. The 432 samples of raw goat milk collected in a period of two years and analysed by the use of an electronic cryoscope gave a mean value of FPD: $-0.565{\pm}0.01^{\circ}C$. Statistical significant differences were found between the morning and evening milk. The evening milk showed better quality considering the lactose and others dissolved solutes. Among the Brown, Saanen and Anglo-nubian goats, the greatest increase in FPD, occurred in the Anglo-nubian breed. The statistical analysis revealed a significant breed difference (p<0.05), when climate variation was observed. The superior and inferior values found to the FPD of the caprine milk (-0.545 to $-0.585^{\circ}C$), is important in establishing regional rules, to improve the quality control criteria and legal interpretation of standards found in the pertinent legislation. The results are also important to improve herd management so that one can increase the animal production which will affect the technological composition, and the nutritional characteristics of the resultant products.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.7-8
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• 2014

Latex-modified concrete using ready mix concrete (R-LMC) was developed for application of building construction project (specifically, the rooftop of a parking garage unable to use heavy equipments for bridge deck overlay) due to three major outstanding properties of R-LMC; bond strength, resistance of cracks at early age, and resistance of freezing and thawing. However, R-LMC at the placement stage is required to be sufficiently cured because R-LMC is very sensitive to rate of evaporation of surface moisture. This study focused on effects of different curing methods and climate condition on cracks on the surface of hardened R-LMC considering the chart of rate of evaporation of surface moisture from concrete provided by American Concrete Institute in manual for placement of latex modified concrete.