• 한국환경과학회지
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• 제19권9호
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• pp.1109-1118
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• 2010

Characteristics of precipitation and temperature in Ulleung-do and Dok-do were analyzed with hourly accumulated precipitation and mean temperature data obtained from Automatic Weather System(AWS) for latest four years(2005~2008). In Ulleung-do, total annual mean precipitation for this period is 1,574.4 mm, which shows larger amount than 1434.2 mm of whole Korean peninsula for latest 10 years(1999~2008) and 1,236.2 mm at Ulleung-do on common years(1971~2000), shows that the trend of precipitation gradually increases during the recent years. This amount is also 1.4 times larger than the total annual mean precipitation of 660.1 mm in Dok-do. Mean precipitation intensity(mm $h^{-1}$) at each time of a day in each month at Ulleung-do represents that the maximum values larger than $3.0\;mm\;h^{-1}$ were shown in May and on 0200 LST, whereas these were found in August and 0700 LST with $3.1\;mm\;h^{-1}$ in Dok-do. The difference of the precipitation amount and its intensity between Uleung-do and Dok-do is explained by the topological effect came from each covering area, and this fact is also identified from similar comparison of the precipitation characteristics for the islands in West Sea. The annual mean temperature of $14.0^{\circ}C$ in Dok-do is $1.2^{\circ}C$ higher than that of $12.8^{\circ}C$ in Ulleung-do. Trends of monthly mean temperature in both islands are shown to increase for the observed period.

• 대기
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• 제33권4호
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• pp.367-385
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• 2023

The variabilities of precipitation and particulate matters (i.e., PM₁₀ and PM_2.5) and the scavenging efficiency of PMs by precipitation were quantified using long-term measurements in Seoul, Korea. The 21 years (2001~2021) measurements of precipitation and PM₁₀ mass concentrations, and the 7 years (2015~2021) of PM_2.5 mass concentrations were used. Statistical analysis was performed for each period (i.e., year, season, and month) to identify the long-term variabilities of PMs and precipitation. PM₁₀ and PM_2.5 decreased annually and the decreasing rate of PM₁₀ was greater than PM_2.5. The precipitation intensity did not show notable variation, whereas the annual precipitation amount showed a decreasing trend. The summer precipitation amount contributed 61.10% to the annual precipitation amount. The scavenging efficiency by precipitation was analyzed based on precipitation events separated by 2-hour time intervals between hourly precipitation data for 7 years. The scavenging efficiencies of PM₁₀ and PM_2.5 were quantified as a function of precipitation characteristics (i.e., precipitation intensity, amount, and duration). The calculated average scavenging efficiency of PM₁₀ (PM_2.5) was 39.59% (35.51%). PM₁₀ and PM_2.5 were not always simultaneously scavenged due to precipitation events. Precipitation events that simultaneously scavenged PM₁₀ and PM_2.5 contributed 42.24% of all events, with average scavenging efficiency of 42.93% and 43.39%. The precipitation characteristics (i.e., precipitation intensity, precipitation amount, and precipitation duration) quantified in these events were 2.42 mm hr^-1, 15.44 mm, and 5.51 hours. This result corresponds to 145% (349%; 224%) of precipitation intensity (amount; duration) for the precipitation events that do not simultaneously scavenge PM₁₀ and PM_2.5.

• Journal of Ecology and Environment
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• 제33권1호
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• pp.37-45
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• 2010

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 $2.40^{\circ}C$ 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 $5.50^{\circ}C$ 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.

• 대한토목학회논문집
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• 제32권3B호
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• pp.185-192
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• 2012

본 연구에서는 가뭄 취약성 지표를 선정하고, 경향성 검정에 따른 지수 산정을 실시하였다. 4대강 살리기의 일환으로 새로이 설치될 보 중 금강 및 낙동강 유역 10개 지점을 선정하였다. 지표는 수자원, 강우, 인문 분야 등 3개 분야 10개 지표를 선정하였다. 10개 지표는 연 최저 및 평균 하천수위와 지하수위, 무강우일수, 강우집중률, 강우편차율, 1인당 가용수자원량, 물재정 건전성, 물이용 공평성으로 이루어져 있다. 10개 지표의 시계열 자료를 정리하여 Mann-Kendall, Hotelling-Pabst, 그리고 Sen trend test를 실시하여 지수를 산정하였다. 연구 결과 구미보, 상주보, 합천보 등 낙동강 유역에 위치한 연구 지점들이 대체적으로 취약한 것을 알 수 있었고, 금강유역은 낙동강에 비해 비교적 취약성이 낮은 것을 알 수 있었다.

• 한국제4기학회지
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• 제17권2호
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• pp.47-54
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• 2003

Climate of Mongolia is a driven force on natural conditions as well as socio-economic development of the country. Due to the precariousness of climate conditions and traditional economic structure, natural disasters, specially disasters of meteorological and hydrological origin, have substantial effect upon the natural resources and socio-economic sectors of Mongolia. Mongolia's climate is characterized by high variability of weather parameters, and high frequency and magnitude of extreme climate and weather events. During the last few decades, climate of the country is changing significantly under the global warning. The annual mean air temperature for the whole territory of the country has increased by $1.56^{\circ}C$ during the last 60 years,. The winter temperature has increased by $1.56^{\circ}C$. These changes in temperature are spatially variable: winter warming is more pronounced in the high mountains and wide valleys between the mountains, and less so in the steppe and Gobi regions. There is a slight trend of increased precipitation during the last 60 years. The average precipitation rate is increased during 1940-1998 by 6%. This trend is not seasonally consistent: while summer precipitation increased by 11 %, spring precipitation decreased by 17. The climate change studies in Mongolia show that climate change will have a significant impact on natural resources such as water resources, natural rangeland, land use, snow cover, permafrost as well as major economic activities of arable farming, livestock, and society (i.e. human health, living standards, etc.) of Mongolia. Therefore, in new century, sustainable development of the country is defined by mitigating and adaptation policies of climate change. The objective of the presentation is to contribute one's idea in the how to reflect the changes in climate system and weather extreme events in the country's sustainable development concept.

• 한국재료학회지
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• 제26권5호
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• pp.235-240
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• 2016

Appropriate thermo-mechanical properties of nickel-based superalloys are achieved by heat treatment, which induces precipitation and solid solution hardening; thus, information on the temperature ranges of precipitation and dissolution of the precipitates is essential for the determination of the heat treatment condition. In this study, thermal analyses of nickel-based superalloys were performed by differential scanning calorimetry method under conditions of various heating rates of 5, 10, 20, or 40K/min in a temperature range of 298~1573K. Precipitation and dissolution temperatures were determined by measuring peak temperatures, constructing trend lines, and extrapolating those lines to the zero heating rate to find the exact temperature under isothermal condition. Determined temperatures for the precipitation reactions were 813, 952, and 1062K. Determined onset, peak, and offset temperatures of the first dissolution reaction were 1302, 1388, and 1406K, respectively, and those values of the second dissolution reaction were 1405, 1414, and 1462K. Determined solvus temperature was 1462K. The study showed that it was possible to use a simple method to obtain accurate phase transition temperatures under isothermal condition.

• 한국수자원학회논문집
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• 제38권10호
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• pp.885-894
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• 2005

1970년대 이후, 우리나라는 산업화에 따른 급격한 도시화가 이루어졌다. 본 논문에서는 우리나라의 대표적인 도시인 서울특별시 및 6대 광역시의 1973년부터 2003년까지의 31개년의 강수랑 자료를 이용하여 강수량의 변화에 대하여 분석하였다. 이와 함께 도시화에 따른 강수량의 변동성을 평가하기 위해서 비도시 지역을 선정하였으며 도시 지역의 강수량 변화와 비교하였다. 도시 지역과 비도시 지역의 연강수량, 계절별 강수량, 지속 시간 1시간 및 24시간연최대 강수량에 대해 임의기간에 따른 평균 분석, 경향성 분석, 변동성 분석, 비매개변수적 빈도 해석을 수행한 결과, 도시화 지역에서 비도시화 지역보다 강우 증가율이 더 컸으며, 특히 여름 강수량의 증가량이 두드러졌다.

• Water Engineering Research
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• 제5권3호
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• pp.111-121
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• 2004

For the long-term strategic water resources planning, forecasting the future streamflow change is important to meet the demand of a growing society. The streamflow variation to the decade-long precipitation was investigated for the two major stage gauging stations in Korea. Precipitation and runoff characteristics have been analyzed at Yongwol stream stage in the Han River as well as Sutong stream stage in the Kum River for the future water resources management strategies. Monte Carlo method has been applied to estimate the future precipitation and runoff. Based on the trend line of 10-year moving average of runoff depth for the historical runoff records, the relation between runoff and the time variation was examined in more detail using regression analysis. This study showed that the surface flows have been significantly decreased while precipitation has been stable in these basins. Decreasing in runoff reflects the regional watershed characteristics such as forest cover changes. The findings of this study could contribute to the planning and development for the efficient water resources utilization.

• 한국기후변화학회지
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• 제2권2호
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• pp.133-141
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• 2011

본 연구에서는 약 100년 기상 관측 자료가 축적된 강릉의 기온과 강수량 자료를 중심으로 기후변화 추세를 분석하여, 강원 지방의 기후변화 경향을 파악하고자 하였다. 지난 98년(1912~2009년)간 강릉의 연평균 기온은 $1.4^{\circ}C$ 상승하였으며, 연강수량은 14.7% 증가하였다. 강수일수는 감소하였고, 강수량은 증가하여 결과적으로 강수강도가 증가하였다. 기온 자료를 기준으로 정의된 자연계절의 변화를 보면 봄과 여름의 시작일이 빨라졌고, 가을과 겨울의 시작일은 늦어졌다. 또한, 여름은 한 달 정도 길어졌고, 겨울은 한 달 가량 짧아졌다. 강원도 7개 기상 관측 자료를 평균한 강원 지역의 연평균 기온은 지난 37년(1973~2009년) 동안 $0.8^{\circ}C$ 상승하였고, 연평균 강수량은 21% 증가하였다. 지역별로 살펴보면 연평균 기온의 경우 원주에서 $1.6^{\circ}C$로 가장 높은 상승 추세를 보였고, 속초에서 $0.4^{\circ}C$로 가장 낮은 상승 추세를 나타냈다. 연강수량의 변화 추세는 대관령에서 22.2%로 가장 높게 나타났고, 원주가 12.0%로 가장 낮았다.

• 한국농림기상학회지
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• 제1권2호
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• pp.110-118
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• 1999

This experiment was conducted to characterize the vertical transport trend of dissolved elements through throughfall, stemflow, effluent from Ao layer, and leachate out of soil profile on Pinus koraiensis stand in Experimental Forest of Kyunghee University, located in Kwangju, Kyunggi province for 12 months from July, 1998 to Jun, 1999. In addition, we investigated the content of dissolved elements and the factors influencing the water chemistry concentrations separately collected from the field. Water movement in the process of throughfall and stemflow from precipitation, and rainfall leached from Ao layer into soil water was governed by concentration of through fall, precipitation, rainfall intensity, seasonal variation, and other factors. Also, smaller changes of pH in soil water than that of dissolved elements in soil water could contribute buffer capacity, as well as balancing the concentration between cations and anions.