• Journal of Environmental Science International
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• v.17 no.6
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• pp.657-669
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• 2008

Lately extreme weather event is occurring because of the global warming. Especially disaster due to the extreme heat are increasing but the definition and the standard of the extreme heat is obscure until now. So this study established the extreme heat standard by using the number of daily deaths. As a result, considering the climate of the megalopolis using daily maximum heat index and daily maximum temperature was the best for the standard of the extreme heat. And it showed that extreme heat lasted for 2 days affects the death toll the most. The regional incidence of the extreme heat is highest at August and July, September and June is following.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.767-780
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• 2009

This study investigates the standard, duration period and excess mortality of extreme heat using the standardized daily mortality data from 1991 to 2004, establishing a standard threshold Criteria for Heat Health Watch Warning System in Korea. It ultimately aims to provide the guidance in building up Heat Health Watch Warning System for Korea by suggesting the standard to quantify thermal stress from heat. The standard threshold Criteria for Heat Health Watch Warning System for Seoul metropolitan city takes into account both daily maximum temperature and daily maximum heat index(HI) and consists of four phases; caution, extreme caution, danger, and extreme danger. Extreme caution phase and danger phase are used as the advisory and warning of extreme heat, respectively. Since the nationwide distribution of the frequency of extreme heat day and the excess mortality rate shows little difference across regions, the standard threshold Criteria for Heat Health Watch Warning System for Seoul metropolitan city can be used for other regions.

• Journal of Environmental Science International
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• v.16 no.2
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• pp.233-239
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• 2007

In the coastal wetland the mud is consist of fine particles, which means that it is characterized by small gap, and heat transfer is obstructed since moisture is found between the gaps. The relationship between net radiation ($R_N$) and soil heat flux($H_G$) shows a counterclockwise hysteresis cycle, which refer to a time lag behind in the maximal soil heat fluxes. The albedo is independent of seasonal variation of the vegetation canopy which plays very important roles to store and control the heat in the atmospheric surface layer.

• Atmosphere
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• v.17 no.3
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• pp.281-289
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• 2007

Micrometeorlogical and upper air observation have been conducted in order to determine the atmospheric boundary layer depth based on data from satellite and automatic weather systems. Terra/MODIS temperature profiles and sensible heat fluxes from the gradient method were used to estimate the mixed layer height over a coastal region. Results of the integral model were in good agreement with the mixed layer height observed using GPS radiosonde at Wolsung ($35.72^{\circ}N$, $129.48^{\circ}E$). Since the variation of the mixed layer height depends on the surface sensible heat flux, the integral model estimated properly the mixed layer height in the daytime. The buoyant heat flux, which is more important than the sensible heat flux in the coastal region, must be taken into consideration to improve the integral model. The vertical structure of atmospheric boundary layer can be analyzed only with the routine data and the satellite data.

• Asian Journal of Atmospheric Environment
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• v.9 no.3
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• pp.214-221
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• 2015

This study considers mean skin temperature to calculate expected temperature using the new heat balance model because the skin temperature is the most important element affecting the heat balance outdoors. For this, we measured the skin temperature in high temperature condition of Korea and applied it to calculate the expected temperature. The calculated expected temperature is compared with the result calculated using previous models which use the estimated mean skin temperature by considering metabolic rate only. Results show that the expected temperatures are higher when measured mean skin temperature is applied to the model, compared to the expected temperature calculated by applying mean skin temperature data calculated using metabolic rate like previous models. The observed mean skin temperature was more suitable for outside conditions and expected temperature is underestimated when mean skin temperature calculated by the equation using metabolic rate is used. The model proposed in this study has a few limitations yet, but it can be applied in various ways to facilitate practical responses to extreme heat.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.832-845
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• 2024

Reactor cavity cooling systems (RCCSs) comprising passive safety features use the atmosphere as a coolant, which cannot be lost. However, their drawback is that they are easily affected by atmospheric disturbances. To realize the commercial application of the two types of passive RCCSs, namely RCCSs based on atmospheric radiation and atmospheric natural circulation, their safety must be evaluated, that is, they must be able to remove heat from the reactor pressure vessel (RPV) surface at all times and under any condition other than under normal operating conditions. These include both expected and unexpected natural phenomena and accidents. Moreover, they must be able to eliminate the heat leakage emitted from the RPV surface during normal operation. However, utilizing all of the heat emitted from the RPV surface increases the degree of waste heat utilization. This study aims to understand the characteristics and degree of passive safety features for heat removal by comparing RCCSs based on atmospheric radiation and atmospheric natural circulation under the same conditions. It was concluded that the proposed RCCS based on atmospheric radiation has an advantage in that the temperature of the RPV could be stably maintained against disturbances in the ambient air.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.551-561
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• 2008

In order to clarify the impact of anti-heat insulation pavement on the thermal structure of atmospheric boundary layer, field experiments and numerical simulations were carried out. Field experiment with various pavements were also conducted for 24 hours from 09LST 19 June 2007. And numerical experiment mainly focused on the impact of albedo variation, which is strongly associated with thermal characteristics of insulated pavement materials, on the temporal variation of planterly boundary layer. Numerical model used in this study is one dimension model with Planterly Boundary Layer developed by Oregon State University (OSUPBL). Because anti-heat insulation pavement material shows higher albedo value, not only maximum surface temperature but also maximum surface air temperature on anti-heat insulation pavement is lower than that on asphalt. The maximum value of surface temperature only reach on $49.5^{\circ}C$. As results of numerical simulations, surface sensible heat flux and the height of mixing layer are also influenced by the values of albedo. Therefore the characteristics of urban surface material and its impact on atmosphere should be clarified before the urban planning including improvement of urban heat environment and air quality.

• Journal of Environmental Science International
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• v.18 no.7
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• pp.781-796
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• 2009

The current standard level of Heat Health Watch Warning System consider both daily maximum temperature and daily maximum heat index(HI), but current standard could not consider daily maximum HI due to the difficulties in forecasting when we consider both daily maximum temperature and daily maximum HI and no considering HI because relative humidity could not observed for some regions. So, Newly established standard level of Heat Health Watch Warning System is based on daily maximum temperature exceeding $30^{\circ}C$ for two consecutive days or daily minimum temperature exceeding $25^{\circ}C$ and daily maximum temperature exceeding $30^{\circ}C$. These days are called "extreme heat days". On extreme heat days, the standard of extreme heat advisory is based on daily maximum temperature among exceeding $32.7^{\circ}C$ and not exceeding $34.8^{\circ}C$, and extreme heat warning is based on daily maximum temperature exceeding $34.8^{\circ}C$. ANOVA analysis was carried out using the data of Seoul Metropolitan City in 1994 to check the robustness of the new standard level of Heat Health Watch Warning System from this study, in particular for mortality variable. The results reveal that the new standard specifies excess mortality well, showing significance level of 0.05 in the difference of excess mortality for each phase.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.523-537
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• 2008

In Korea, the global warming leads to more frequent high temperature region. increasing the need for research into physical damage caused by high temperature. We therefore analyzed the differences of mortality, caused by extreme heat, among gender and age. We also examined the trend of mortality from high temperature-sensitive diseases. Women are more affected by exposure to high temperature than are men; People over 65 years old have higher mortality rate (1.5 times) than under 65. As for high temperature-related diseases, cerebrovascular disease was the number one cause of death, and chronic lower respiratory disease and cardiovascular disease followed.

• Journal of the Korean earth science society
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• v.26 no.6
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• pp.560-572
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• 2005

This study investigates the characteristics of atmospheric circulation and the heat source $(Q_1)$ related to the winter cold surge in Korea from 1979 to 1999. The occurrence frequency of cold surge is about one event per year and $60\%$ of the total events occurred during the former period, before 1989. During the cold surge, the pressure pattern shows more dominant east-west dipole circulation pattern in the lower troposphere and the effect of upper level trough is stronger than normal cases. Temperature falling pattern over Korea shows that the pattern opposite to the temperature structure over Lake Baikal and temperature change has opposite signs between the low-middle level and upper level, with the boundary at 400 hPa. The analysis of heat source shows that atmospheric cooling by cold advection during the cold surge is balanced by adiabatic warming due to downward motion, indicating that the movement path of cold core is associated with that of heat sink. Therefore, the movement mechanism of the heat source and sink should be well known for understanding the maintenance mechanism of cold surge and predicting cold surges.