Temperature In Seoul Research Articles

Robust nonparametric derivative estimator

In this paper, a robust nonparametric derivative estimator is proposed to estimate the derivative function of nonparametric regression when the data contain noise and have curves. A robust estimation of the derivative function is important for understanding trend analysis and conducting statistical inferences. The methods for simultaneously assessing the functional relationship between response and covariates as well as estimating its derivative function without trimming noisy data are quite limited. Our robust nonparametric derivative functions were developed by constructing three weights and then incorporating them into kernel-smoothing. Various simulation studies were conducted to evaluate the performance of our approach and to compare our proposed approach with other existing approaches. The advantage of our robust nonparametric approach is demonstrated using epidemiology data on mortality and temperature in Seoul, South Korea.

Diurnal and Seasonal Variations in the Effect of Urban Environmental Factors on Air Temperature: A Consecutive Regression Analysis Approach.

This study investigates the diurnal and seasonal variations in the effect of environmental features on air temperature in Seoul, Korea. We expect that this study will lead to the identification of factors that can be applied for urban heat island mitigation strategies in summer without leading to an unintended result in winter. As our dependent variable, we employed the smoothed 31-day moving average of air temperatures, where we controlled the seasonal variation by normalizing the values observed from 247 automatic weather stations (AWS) from 2015 to 2016. Subsequently, we conducted consecutive log–log regression analyses of each day to examine patterns of change in regression coefficients and the significance of each independent variable. For independent variables, we applied built environment features including albedo, land-use, average building floors, the sky view factor, and green and water areas. This study provides analytical results regarding the relationship between environmental factors and air temperature. This study also addresses imperative issues for planners, especially regarding albedo, wind path, building geometry, and land use types. Finally, this study gives useful insights for managing the diurnal and seasonal variations of urban thermal environment in the mega-city.

The Effects of Land Use Zoning and Densification on Changes in Land Surface Temperature in Seoul

This study investigated how changes in land surface temperature (LST) during 2004 and 2014 were attributable to zoning-based land use type in Seoul in association with the building coverage ratio (BCR), floor area ratio (FAR), and a normalized difference vegetation index (NDVI). We retrieved LSTs and NDVI data from satellite images, Landsat TM 5 for 2004 and Landsat 8 TIRS for 2014 and combined them with parcel-based land use information, which contained data on BCR, FAR, and zoning-based land use type. The descriptive analysis results showed a rise in LST for the low- and medium-density residential land, whereas significant LST decreases were found in high-density residential, semi-residential, and commercial areas over the time period. Statistical results further supported these findings, yielding statistically significant negative coefficient values for all interaction variables between higher-density land use types and a year-based dummy variable. The findings appear to be related to residential densification involving the provision of more high-rise apartment complexes and government efforts to secure more parks and green spaces through urban redevelopment and renewal projects.

Changes in the Relationship between Particulate Matter and Surface Temperature in Seoul from 2002–2017

This study focuses on the changes over time in the relationship between surface temperature and particulate matter (PM) concentration over Seoul using long-term observational data. Correlation coefficients between the daily mean PM10 concentration and surface temperature were calculated to investigate the relationship between the two. The PM10 and temperature displayed a strong positive correlation, suggesting the increase in PM was driven by large-scale synoptic patterns accompanying such high temperatures. It was found that the correlation coefficient in 2002–2009 was significantly higher than that of 2010–2017, indicating that the relationship between PM10 concentration and temperature has weakened over time in recent decades. Correlation coefficients between daily averaged temperature and the PM10 of each year were calculated to account for the decreased correlation in the most recent decade. We found that the correlation coefficients between surface temperature and PM of each year exhibited a clear negative correlation with the longitudinal position of the Siberian High, suggesting that the position of the Siberian High might affect the strength of the relationship between PM concentration and temperature over Seoul. We also found that the eastward shift of the Siberian High reduces the standard deviation of pressure over Seoul, indicating reduction of synoptic perturbation. These results imply that the eastward shift of the Siberian High in recent decades might weaken the relationship between the PM and surface temperature over Seoul. This study suggests that the relationship between PM and meteorological variables is changing over time through changes in large climate variability.

Correlation between the occurrence of acute gastroenteritis in children and regional temperature at a tertiary hospital emergency department in Korea

Purpose Several studies have investigated the association between acute gastroenteritis (AGE) and regional temperatures. We aimed to investigate the correlation between the occurrence of AGE and regional temperature in Korean children. Methods We reviewed the clinical characteristics of children aged 18 years or younger with AGE, defined according to the International Statistical Classification of Diseases, 10th Revision codes, who visited a Korean tertiary hospital emergency department (ED) between 2006 and 2016, and compared the children who were discharged from the ED and those who were hospitalized. Data on temperature in Seoul, Korea during the period were obtained from the Korea Meteorological Administration. Subsequently, we assessed correlations between the monthly mean numbers of the children with AGE and monthly mean temperature using Pearson’s correlation analysis. Results A total of 31,931 children with AGE visited the ED. Vomiting was the most common manifestation (62.0%). Fever, chills, cough, and sputum were more frequent in the hospitalized children (P < 0.05). Hospitalization rate was highest (2.7%) and monthly mean temperature was lowest (-2.4。C) in January. We observed negative correlations between the monthly mean numbers of the children with AGE and the monthly mean temperature (for ED visit, r = -0.845; for hospitalization, r = -0.923). Conclusion Children with AGE tend to visit the ED, and undergo hospitalization during the cold weather. This finding could help the guardians to expect the occurrence of AGE, and physicians to facilitate the allocation of resources for emergency medicine in winter. Key Words: Association; Child; Epidemiology; Gastroenteritis; Korea; Temperature

Design and Analysis of Heat Exchanger Using Sea Water Heat Source for Cooling

Purpose: The temperature in Seoul has risen 3 times more than the average global temperature increase for the past 100 years. Today, summer starts 15 days earlier than the early 20th century and is 32 days longer. This tendency causes rapid increase of cooling energy demand. Following this effect, seawater heat resources are to be used as an countermeasure for global warming. Incheon Port near the Western Sea has the lowest water temperature in the winter in South Korea in which it is suitable to use seawater cold heat resources. Method: The cold heat resource is gained from seawater when the water temperature is the lowest in the winter time and saved in a seasonal thermal storage. This can be used as cold heat resource in the summer time. A heat exchanger is essential to gain seawater cold energy. Due to this necessity, sea water heat resource heat exchangers are modeled by heat transfer equations and the fluid characteristics are analyzed. Also, a CFD (computational fluid dynamics) program is used to conduct simulation on the fluid characteristics of heat exchangers. The analyzed data of deducted from this process are comprehensively analyzed and discussed. Result: Regarding the performance of the heat exchanger, the heat exchanger was operated following the prediction within the range of heat transfer rate of minimum 3.3KW to maximum 33.6KW per device. In the temperature change analysis of the heat exchanger, fluid analysis by heat transfer equations almost corresponded to the temperature change by CFD simulation. Therefore, it is considered that the results of this study can be used as design data of heat exchangers.

The Impact of Extreme Temperature in Seoul, Korea through 1995 to 2011; Susceptible Populations and Temporal Variation of the Impact

Backgrounds: In recent years, the impact of extreme temperature on mortality has been studied in Seoul, Korea. However, only few studies were conducted for heat and cold extremes to find susceptible groups by causes and to see if temporal variation of the effect alters by those groups. Objectives: We aimed to analyze the association of extreme temperature with cause specific mortality on susceptible groups and to see if the temporal variation varies on those populations. Methods: We obtained data on daily mortality, temperatures and particulate matter(PM) in Seoul, Korea from 1995 to 2011. We applied time-series analysis with distributed lag non-linear model to set lag structures for temperature and PM up to 30 days. Seasonal and time trend were adjusted. Age, gender and mortality were stratified. To see a temporal variation of the impact of extremes, we separated by windows of five years. Results: The overall heat effect for all-cause mortality was a 8.8% (95% CI: 5.2, 12.6) increase in risk comparing 29? to 22?. For cardiovascular mortality on people between 20 and 64 year-olds, the increase in risk was a 20.8% (0.86, 44). Among them, males showed higher risk increment to 29% (2.8, 63.0). Heat effect-related mortality after a year of 2000 has declined and this pattern has been markedly on elders. As we using indicators for heat wave, estimates was bigger but declining pattern was attenuated. For cold effect, the overall increment in risk of all-cause mortality was a 6.5% (1.0, 12.3) and of cardiovascular mortality on people from 20 to 64 year-olds was 42.1% (3.9, 94.4) comparing -8°C to 4°C. No consistently varying trends of cold effect was found. Discussions: Our finding suggests susceptible groups may vary by cause specific mortality and anthropogenic factors such as age and sexuality. In this study, the declining pattern of temporal variation on heat effect was markedly on elders. This may indicate that further studies is needed for younger population.

Vulnerability assessment due to high temperature in Seoul, South Korea

Background Health impact of high temperature has been reported since the early 20th century. In South Korea, it is reported that mortality increases with temperature above city-specific thresholds ...

A Bayesian structural-change analysis via the stochastic approximation Monte Carlo and Gibbs sampler

In this article, we propose a Bayesian approach to estimate the multiple structural change-points in a level and the trend when the number of change-points is unknown. Our formulation of the structural-change model involves a binary discrete variable that indicates the structural change. The determination of the number and the form of structural changes are considered as a model selection issue in Bayesian structural-change analysis. We apply an advanced Monte Carlo algorithm, the stochastic approximation Monte Carlo (SAMC) algorithm, to this structural-change model selection issue. SAMC effectively functions for the complex structural-change model estimation, since it prevents entrapment in local posterior mode. The estimation of the model parameters in each regime is made using the Gibbs sampler after each change-point is detected. The performance of our proposed method has been investigated on simulated and real data sets, a long time series of US real gross domestic product, US uses of force between 1870 and 1994 and 1-year time series of temperature in Seoul, South Korea.

Changes in the association between summer temperature and mortality in Seoul, South Korea

The health impact of climate change depends on various conditions at any given time and place, as well as on the person. Temporal variations in the relationship between high temperature and mortality need to be explored in depth to explain how changes in the level of exposure and public health interventions modify the temperature-mortality relationship. We examined changes in the relationship between human mortality and temperature in Seoul, which has the highest population in South Korea, considering the change in population structure from 1993-2009. Poisson regression models were used to estimate short-term temperature-related mortality impacts. Temperature-related risks were divided into two "time periods" of approximately equal length (1993 and 1995-2000, and 2001-2009), and were also examined according to early summer and late summer. Temperature-related mortality in summer over the past 17 years has declined. These decreasing patterns were stronger for cardiovascular disease-related mortality than for all non-accidental deaths. The novel finding is that declines in temperature-related mortality were particularly noteworthy in late summer. Our results indicate that temperature-related mortality is decreasing in Seoul, particularly during late summer and, to a lesser extent, during early summer. This information would be useful for detailed public health preparedness for hot weather.

Statistical Interpretation of Climate Change in Seoul, Korea, over the Last 98 Years

I conducted extensive analyses of daily weather data of precipitation and temperature monitored from the Surface Synoptic Meteorological Station in Seoul from 1 October 1907 to 31 December 2009 to understand how the climate is changing and the ecological implications for Seoul, Korea. Statistical analyses of the data, including the lengths of seasons and growing degree-days (GDD), showed a clear warming trend in the Seoul area over the study period. The mean daily temperature in Seoul increased by 2.40°C over the period of one hundred years, which was about three times faster than the global trend and it was striking to notice that mean daily temperature in Seoul in recent 30 years was increasing with the rate of 5.50°C per hundred years, which is an extremely fast rate of increase in temperature. In the last 100 years, an increase in the number of summer days was apparent, coupled with a reduction in the average number of winter days for about 27 to 28 days based on the analysis of mean daily temperature. Although the lengths of spring and autumn have not changed significantly over the century, early initiations of spring and late onsets of autumn were quite apparent. Total annual precipitation significantly increased at the rate of 2.67 mm/year over the last 100 years, a trend not apparent if the analysis is confined to periods of 30 to 40 years. The information has the potential to be used not only for better understanding of ecological processes and hydrology in the area, but also for the sustainable management of ecosystems and environment in the region.

Different Risks of Traumatic and Non-Traumatic Injuries Attributable to Temperature in Seoul, Korea

ISEE-0520 Background and Objective: Several studies reported that the occurrence of injury has seasonality and the fluctuation depends on temperature. Although the injury occurs from various factors, many studies on injury have been focused on specific diseases or sports. In addition, there were little studies on the effect of temperature on occurrence of injury. Therefore, the aim of this study is to evaluate the association between daily counts of sub-categories of injury such as traumatic and non-traumatic injuries and daily mean temperature. Methods: Data on injury were derived from the emergency ambulance delivery database of the National Emergency Management Agent (NEMA) in Korea from 2006 to 2008. We counted daily ambulance delivery according to four categories, such as total injury, traumatic and non-traumatic injuries as well as total disease. The classification of injury was based on International Classification of External Cause of Injury (ICECI). The generalized additive models (GAM) were used to examine the association between the daily counts of ambulance delivery by four categories and the mean temperature, controlling for confounding factors such as relative humidity, national holidays, and long-term trends. Results: The daily counts of total injury, traumatic injury, non-traumatic injury and total disease showed strongly seasonality. We found that rate ratio (RR) of daily counts of total injury was 1.0047 (95% CI = 1.0033–1.0063) corresponding to 1°C increase of mean temperature. The RR of non-traumatic injury (1.0114, 95% CI = 1.0095–1.0132) was much higher than of traumatic injury (1.0022, 95% CI = 1.0004–1.0041), even controlling for confounding factors. The association between total disease and temperature was also significant (RR = 1.0061, 95% CI = 1.0048–1.0074). Conclusion: The occurrence of injury, attributable to temperature, were different depending on whether the type of injury is traumatic or non-traumatic. The effect of temperature on non-traumatic injury was higher than traumatic injury.

수도권지역 대기질 예측을 위한 기상장 모델의 바람장과 온도장 비교 연구

The MM5, RAMS and WRF, meteorological models have provided the dynamical parameters as inputs to air quality model. A major content of this study is that significant characteristics of three models for high-ozone occurrence analyze for surface wind and air temperature fields and compare with observation data in Seoul metropolitan area. An analysis of air temperature field revealed that location of core in high temperature of MM5 and WRF differed from that of RAMS. MM5 and WRF indicated high temperature in Seoul but RAMS represented it on the outskirts of Seoul. MM5 and WRF were underestimated maximum temperature during daytime but RAMS simulated similar value with observation data. Surface wind field with three models, it was shown many differences at horizontal distribution of wind direction. RAMS indicated weak wind speed in land and strong sea breeze at coastal areas than MM5 and WRF. However wind speed simulated by three model were overestimated during both daytime and nighttime.

일일 최고기온의 변화에 대한 추정

한국의 네 개 도시(서울, 대구, 춘천, 영천)의 일일 최고기온을 모형화하여, 이에 적합한 분포를 제안하고 분포의 적합성을 여러 가지 방법에 의하여 검토하였다. 제안된 분포는 극단간 분포의 일종이며, 적합성 검토는 카이제곱 적합도 검정, Q-Q plot,확률 그림과 5000번의 모의실험을 통하여 허용한계를 구하였다 그 결과 제안된 극단간 분포(Extreme Value Distribution)가 일일 최고기온을 잘 설명하고 있음을 확인할 수 있었다. 논문에서 나타난 실제 데이터의 그림은 서울의 1월과 6월을 중심으로 하였고, 대상지역의 2006년과 100년 후 2105년의 평균기온과, 제 안된 극단값 분포에 의해 95% 신뢰구간하에서 일일 최고기온의 평균 상한값을 예측하였다. This investigation on the change of the daily maxima temperature in Seoul, Daegu, Chunchen, Youngchen was triggered by news items such as the earth is getting warmer and a recent news item that said that Korea is getting warmer due to this climatic change. A statistical analysis on the daily maxima for June over this period in Seoul revealed a positive trend of 1.1190 centigrade over the 45 years, a change of 0.0249 degrees annually. Due to the large variation on these maximum temperatures, one can raise the question on the significance of this increase. To check the goodness of fit of the proposed extreme value model, we shown a Q-Q plot of the observed quantiles against the simulated quantiles and a probability plot. And we calculated statistics each month and a tolerance limit. This is tested through simulating a large number of similar datasets from an Extreme Value distribution which described the observed data very well. Only 0.02% of the simulated datasets showed an increase of this degrees or larger, meaning that the probability is very low for such an event to occur.

부산지역의 기후변화와 매립의 관련성에 대한 연구

부산은 서울, 대구 등 내륙도시와는 달리 도시화 과정에 수역의 매립이 포함되어 있어 도시화에 의한 도시기후변화에도 매립의 영향이 있을 것으로 생각된다. 이에 본 연구에서는 한국의 3대 도시인 서울, 부산, 대구의 기후변화요인과 70여 년간의 기상데이터를 비교ㆍ분석하여 부산의 기후변화 특성 및 매립과 기후변화의 관련성에 대해 검토하였다. 그 결과 부산에서 매립이 진행되었다는 점을 제외하면 서울, 부산, 대구의 기후변화 요인에는 큰 차이가 없지만 서울, 대구의 경우는 도시화가 진행됨에 따라 최저기온의 연평균 상승이 현저한 것에 비해 부산은 매립이 진행된 시기에 최고기온의 연평균 상승이 현저함을 밝혔다. Busan has its unique character which differed from inland such as Seoul and Daegu Because Busan is located in coast district of Korea, it could be inferred that the climate change in Busan had been influenced by foreshore reclamation in the urbanization process. The purpose of this study is to investigate the relationship between reclamation of the foreshore and climate change by analysing the climate change over the past 70 years in three metropolitan cities. The conclusion from this study are as follows. 1) There was not a big difference among elements of climate change in three cities. 2) Annual mean minimum temperature in Seoul and Daegu had remarkably increased over the past 70 years. On the other hand, annual maximum temperature in Busan had a sudden rise in the only tome to reclaim the foreshore.