• Journal of the Korean earth science society
• /
• v.32 no.7
• /
• pp.761-769
• /
• 2011

Daily minimum temperature and freezing data of the Seoul weather station ($37^{\circ}$34'N, $126^{\circ}$57'E, Songwol-dong Jongno-gu Seoul, hereinafter Songwol) and freezing data of the Han River station ($37^{\circ}$30'N, $126^{\circ}$57'E, hereinafter Han River) were used to study the long-term variation of the freezing climate for Seoul, Korea, for the period of 100 years from 1907 to 2006. 'Freezing' of Songwol is defined that the water in outdoor fields is frozen, and 'freezing' of the Han River located 6 km away from Songwol is defined as the region 100 meters upstream of the second and fourth piers in the south end of the Han River Bridge is fully frozen. The mean first freezing date for Songwol was October 28, and one for Han River was December 28; these showed a late tendency, with the rate of 0.78 days $decade^{-1}$ and 3.47 days $decade^{-1}$, respectively. The mean annual freezing days was 159.06 days for Songwol and 50.33 days for Han River; each showed a $decade^{-1}$shorter tendency, with rates of 2.01 days $decade^{-1}$ and 5.24 days $decade^{-1}$, respectively. All the seven no-freezing years (1960, 1971, 1972, 1978, 1988, 1991, and 2006) for Han River came after 1950. The mean daily minimum temperatures of the first freezing dates for Songwol and Han River were $0.55^{\circ}C$ and $-12.22^{\circ}C$. The first freezing occurred after 6.43 days for Songwol and after 8.94 days for Han River with daily minimum temperature below $0^{\circ}C$. The annual minimum temperatures of Songwol and Han River exhibited positive correlations with the first freezing date and negative correlations with freezing days. The result shows that the freezing climate change is relevant to temperature change and is a part of overall climate change. By conducting additional studies with various methods and wider region, we will be able to monitor the freezing climate.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.1575-1579
• /
• 2010

본 연구에서는 우리나라 6개 지점(강릉, 서울, 인천, 대구, 부산, 목포)에서 관측한 약 100년간(1912-2009년, 단 1950-1953년 제외)의 일최고/최저기온 및 일강수 자료를 이용하여 각 지점별로 다양한 기후지수를 산출하고 이들의 변화를 살펴보았다. 기온 관련 기후지수로는 여름일수, 영하일수, 결빙일수, 서리일수, 열대야일수, 냉방도일, 난방도일, 일교차, 식물성장일수, 일최고/최저기온의 월최고값 및 월최저값 등을 분석하였으며, 강수 관련 기후지수로 강수량, 강수일수, 강수강도, 호우일수, 미우일수, 최고 일강수 및 5일 연속 최고 강수량, 연속건조일수 및 연속습윤일수, 극한 강수일의 강수량 등을 계산하였다. 다음은 6개 지점의 기후지수를 평균한 결과이다. 6개 지점 모두에서 최저기온의 상승률이 최고기온의 상승률보다 크게 나타남에 따라 분석기간 동안 일교차는 점차 줄어드는 경향($-0.12^{\circ}C$/10년)을 보였고, 최저기온에 근거한 기후지수인 서리일수 (최저기온이 $-5^{\circ}C$ 미만, -2.6일/10년), 영하일수(최고기온이 $0^{\circ}C$ 미만, -1.0일/10년) 등의 감소와 평균기온의 상승에 따른 성장계절길이(growing season length)의 증가(+3.53일/10년)가 뚜렷하게 나타났다. 일강수와 관련된 주요변화로 미우일수(일강수량이 1 $mmday^{-1}$ 이하)는 감소(-0.75일/10년)했지만, 10 $mmday^{-1}$ (+0.32일/10년), 20 $mmday^{-1}$ (+0.27일/10년), 30 $mmday^{-1}$ (+0.25일/10년), 50 $mmday^{-1}$ (+0.17일/10년), 80 $mmday^{-1}$(+0.09일/10년) 이상 내린 강수일수는 증가하였다. 강수강도(강수량이 1 $mmday^{-1}$ 이상일 때의 강수량과 강수일수 기준)는 0.23 $mmday^{-1}$/10년로 증가했다.

• Journal of Korean Society of Transportation
• /
• v.18 no.5
• /
• pp.7-16
• /
• 2000

This paper is focused on verifying time-space repetition of the highway accident and finding the their causes and deterrents. We classify all months into several seasonal groups, develop the model for each seasonal group and analyze the results of these models for Joong-bu highway. The existence of seasonal effect is verified by the analysis or self-organizing map and the accident indices. Agglomerative hierarchical cluster analysis which is used to decide the seasonal groups in accordance with accident patterns, winter group, spring-fall group. and summer group. The accident features of winter group are that the accident rate is high but the severity rate is low. while those of summer group are that the accident rate is low but the severity rate is high. Also, the regression model which is developed to identify the accident Pattern or each seasonal group represents that the season-related factors, such as the amount of rainfall, the amount of snowfall, days of rainfall, days of snowfall etc. are strongly related to the accident pattern of evert seasonal group and among these factors the traffic volume, amount of rainfall. the amount of snowfall and days of freezing importantly affect the local accident Pattern. So, seasonal effect should be considered to the identification of high-risk road section. the development of descriptive and Predictive accident model, the resource allocation model of accident in order to make safety management plan efficient.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.6
• /
• pp.409-412
• /
• 2002

This research was conducted to obtain the fundamental data on salt injury and different responses among cultivars in winter barley (Hordeum vulgare L.). Salts did not affect yield components including number of panicles, stem length, grain number per ear and grain yield while reduced stem dry weight and thousand seed weight significantly with increasing concentrations of salt from 60 to 180 mM. NaCl had less injury effect on barley straw dry weight and thousand seed weight than did $MgSO_4$. Chlorophyll content and relative turgidity in flag leaf were reduced when treated with both salts, while free proline in the salt-treated leaf was increased. Content of proline in salt-treated barley was about 10 folds compared to the control. Based on yield components and physiological traits of flag leaf, the tolerance to salt injury was the greatest in Baegdong, followed by Dongbori#1, Mogpo#55, and Gangbori. The results suggested that salt- stressed barley at reproductive stage had higher free proline content, and that special management in this stage must be considered because salt stress at heading stage affect flag leaf growth as well as yield components Harmfully.