• Title, Summary, Keyword: mean annual frequency

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Spatial Patterns and Temporal Variability of the Haines Index related to the Wildland Fire Growth Potential over the Korean Peninsula (한반도 산불 확장 잠재도와 관련된 Haines Index의 시.공간적 특징)

  • Choi Cwang-Yong;Kim Jun-Su;Won Myoung-Soo
    • Journal of the Korean Geographical Society
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    • v.41 no.2
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    • pp.168-187
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    • 2006
  • Windy meteorological conditions and dried fire fuels due to higher atmospheric instability and dryness in the lower troposphere can exacerbate fire controls and result in more losses of forest resources and residential properties due to enhanced large wildland fires. Long-term (1979-2005) climatology of the Haines Index reconstructed in this study reveals that spatial patterns and intra-annual variability of the atmospheric instability and dryness in the lower troposphere affect the frequency of wildland fire incidences over the Korean Peninsula. Exponential regression models verify that daily high Haines Index and its monthly frequency has statistically significant correlations with the frequency of the wildland fire occurrences during the fire season (December-April) in South Korea. According to the climatic maps of the Haines Index created by the Geographic Information System (GIS) using the Digital Elevation Model (DEM), the lowlands below 500m from the mean sea level in the northwestern regions of the Korean Peninsula demonstrates the high frequency of the Haines Index equal to or greater than five in April and May. The annual frequency of the high Haines Index represents an increasing trend across the Korean Peninsula since the mid-1990s, particularly in Gyeongsangbuk-do and along the eastern coastal areas. The composite of synoptic weather maps at 500hPa for extreme events, in which the high Haines Index lasted for several days consecutively, illustrates that the cold low pressure system developed around the Sea of Okhotsk in the extreme event period enhances the pressure gradient and westerly wind speed over the Korean Peninsula. These results demonstrate the need for further consideration of the spatial-temporal characteristics of vertical atmospheric components, such as atmospheric instability and dryness, in the current Korean fire prediction system.

Characteristics of the Land and Sea Breeze on Cheju island , Korea (제주도 지방의 해륙풍의 특성)

  • 김유근
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.27 no.1
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    • pp.41-55
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    • 1991
  • A study was done to investigate characteristics of the land and sea breeze over Cheju island on the basis of surface meteorological data collected from 1977 to 1986. The results are summarized as follows: The frequency of the land and sea breze was highest in August followed by September, October, May and November in descending order. This indicates that the frequency of the land and sea breeze is higher in fall than in spring, and lowest in winter. The sea breeze began much earlier than any other regions of Korea all the year round, and it began about 30 minutes earlier and ended one hour later in the northern coast than in the southern coast of Cheju island. Meanwhile, the land breeze began about one hour earlier in the southern coast than in the northern coast and ended almost at the same time in both coasts. The annual mean duration of the sea breeze was about one hour longer in the northern coast than in the southern coast, but the land breeze showed an opposite trend. The duration of the sea breeze was longer in summer than in winter and again the land breeze was opposite. Transition period from the sea to the land breeze was relatively long in summer and shout in winter, but transition period from the land to the sea breeze was not different between seasons. The time for a maximum velocity of the sea breeze came earlier in the southern coast than in the northern coast, but that of the land breeze came almost at the same time in both coasts with no seasonal variations. Monthly mean maximum velocity of the sea breeze was greater than that of the land breeze.

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The Effect of Social Support on Elderly Women's Quality of Life (여성노인의 사회적 지지가 삶의 질에 미치는 영향)

  • Hong, Sung-Hee
    • Korean Family Resource Management Association
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    • v.19 no.2
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    • pp.1-26
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    • 2015
  • The purpose of this study was to analyze the quality of life (QoL) of elderly women and the effect of social support on their QoL. The data were used 'urvey on the Elderly in 2011', which was held from 'Ministry of Health & Welfare' and 'Korea Institute for Health and Social Affairs'. Among the total 15,146 respondents, 3,880 of elderly women whose age was over 65, and who did not live together with their married children were included in the analysis. Multiple regression analysis and path analysis were used to analyze the research model. The findings were as follows. First, from the fact that the elderly women showed the highest mean in 'contact frequency with friends' among social support, it seemed that the elderly women contacted their friends more than their children in their old age. Among the support types from their children, elderly women received emotional support, physical support, instrumental support in order and irregular cash as a way of economic support. Second, from the regression results, the most critical factor that affected the QoL of elderly women was 'subjective physical condition level' and 'subjective standard of living' comes next. Third, the most important factor was 'subjective standard of living' from path analysis results, and 'subjective physical condition level' and 'total amount of annual income' in order. Also, social supports such as 'phone call contact frequency with children', 'emotional support from children', phone call contact frequency with relatives', 'phone call contact frequency with friends' positively affected the QoL of elderly women. Therefore, raising social supports from children, relatives, and friends positively contributes to improve the QoL of elderly women directly and indirectly. The results show that social supporters, which is a part of the structural aspects of social support, and types of social support, which lies in functional aspects, directly affect QoL of the elderly women and turn out to be factors that improve the QoL as mediating variables. It is concluded that the social supports can be the most important resources that make up declining personal and social resources in old age and maintain the QoL of elderly women.

Prospect of extreme precipitation in North Korea using an ensemble empirical mode decomposition method (앙상블 경험적 모드분해법을 활용한 북한지역 극한강수량 전망)

  • Jung, Jinhong;Park, Dong-Hyeok;Ahn, Jaehyun
    • Journal of Korea Water Resources Association
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    • v.52 no.10
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    • pp.671-680
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    • 2019
  • Many researches illustrated that the magnitude and frequency of hydrological event would increase in the future due to changes of hydrological cycle components according to climate change. However, few studies performed quantitative analysis and evaluation of future rainfall in North Korea, where the damage caused by extreme precipitation is expected to occur as in South Korea. Therefore, this study predicted the extreme precipitation change of North Korea in the future (2020-2060) compared to the current (1981-2017) using stationary and nonstationary frequency analysis. This study conducted nonstationary frequency analysis considering the external factors (mean precipitation of JFM (Jan.-Mar.), AMJ (Apr.-Jun.), JAS (Jul.-Sept.), OND (Oct.-Dec.)) of the HadGEM2-AO model simulated according to the Representative Concentration Pathway (RCP) climate change scenarios. In order to select external factors that have a similar tendency with extreme rainfall events in North Korea, the maximum annual rainfall data was obtained by using the ensemble empirical mode decomposition (EEMD) method. Correlation analysis was performed between the extracted residue and the external factors. Considering selected external factors, nonstationary GEV model was constructed. In RCP4.5, four of the eight stations tended to decrease in future extreme precipitation compared to the present climate while three stations increased. On the other hand, in RCP8.5, two stations decreased while five stations increased.

Comparison Study on the Various Forms of Scale Parameter for the Nonstationary Gumbel Model (다양한 규모매개변수를 이용한 비정상성 Gumbel 모형의 비교 연구)

  • Jang, Hanjin;Kim, Sooyoung;Heo, Jun-Haeng
    • Journal of Korea Water Resources Association
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    • v.48 no.5
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    • pp.331-343
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    • 2015
  • Most nonstationary frequency models are defined as the probability models containing the time-dependent parameters. For frequency analysis of annual maximum rainfall data, the Gumbel distribution is generally recommended in Korea. For the nonstationary Gumbel models, the time-dependent location and scale parameters are defined as linear and exponential relationship, respectively. The exponentially time-varying scale parameter of nonstationary Gumbel model is generally used because the scale parameter should be positive. However, the exponential form of scale parameter occasionally provides overestimated quantiles. In this study, various forms of time-varying scale parameters such as exponential, linear, and logarithmic forms were proposed and compared. The parameters were estimated based on the method of maximum likelihood. To compare the accuracy of each scale parameter, Monte Carlo simulation was performed for various conditions. Additionally, nonstationary frequency analysis was conducted for the sites which have more than 30 years data with a trend in rainfall data. As a result, nonstationary Gumbel model with exponentially time-varying scale parameter generally has the smallest root mean square error comparing with another forms.

Characteristics of Waves around the Sea near Busan New Port Based on Continuous Long-term Observations during Recent 10 years (최근 10년간 장기연속관측에 근거한 부산항 신항 인근 해역의 파랑특성)

  • Jeong, Weon-Mu;Oh, Sang-Ho;Baek, Won-Dae;Chae, Jang-Won
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.2
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    • pp.109-119
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    • 2012
  • Long-term wave observation was carried out near Busan New Port and the major wave characteristics were analyzed. At Busan New Port, waves from south direction were predominant throughout the year, while waves from the west, developed at the north sea of Geoje island, appeared almost the same frequency in winter season, showing apparent seasonal variation. During the observation period, the significant wave height was mostly less than 1 m, but it reached its maximum of 8.0 m when typhoon Maemi passed on September 2003. Also, the seasonal variation was hardly observed except July. In contrast, seasonal variation was apparent for the significant wave period, whose peak ranges 4~5 s in summer whereas about 3 s in winter. The largest significant wave period was 15.56 s, observed on June 2003. Meanwhile, the annual variation was negligible for mean wave direction as well as significant wave height and period. Further analysis of the wave data acquired for 5 years at 4.5 km south, in the south sea of Daejuk island, confirmed high correlation between the two observation points in summer and vice versa in winter.

Estimation of Design Flood by the Determination of Best Fitting Order of LH-Moments(II) (LH-모멘트의 적정 차수 결정에 의한 설계홍수량 추정(II))

  • 맹승진;이순혁
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.1
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    • pp.33-44
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    • 2003
  • This study was conducted to estimate the design flood by the determination of best fitting order for LH-moments of the annual maximum series at fifteen watersheds. Using the LH-moment ratios and Kolmogorov-Smirnov test, the optimal regional probability distribution was identified to be the Generalized Extreme Value (GEV) in the first report of this project. Parameters of GEV distribution and flood flows of return period n years were derived by the methods of L, L1, L2, L3 and L4-moments. Frequency analysis of flood flow data generated by Monte Carlo simulation was performed by the methods of L, L1, L2, L3 and L4-moments using GEV distribution. Relative Root Mean Square Error. (RRMSE), Relative Bias (RBIAS) and Relative Efficiency (RE.) using methods of L, Ll , L2, L3 and L4-moments for GEV distribution were computed and compared with those resulting from Monte Carlo simulation. At almost all of the watersheds, the more the order of LH-moments and the return periods increased, the more RE became, while the less RRMSE and RBIAS became. The Absolute Relative Reduction (ARR) for the design flood was computed. The more the order of LH-moments increased, the less ARR of all applied watershed became It was confirmed that confidence efficiency of estimated design flood was increased as the order of LH-moments increased. Consequently, design floods for the appled watersheds were derived by the methods of L3 and L4-moments among LH-moments in view of high confidence efficiency.

Climate Change Concerns in Mongolia

  • Dagvadorj, D.;Gomboluudev, P.;Natsagdorj, L.
    • The Korean Journal of Quaternary Research
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    • v.17 no.2
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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.

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A Study on Intention to live in Cohousing According to Housing Value (주거가치에 따른 코하우징 거주의사에 관한 연구)

  • Cho, Jeong-Hyun;Hong, Seo-Jung;Kwak, Yu-Mi;Kwak, In-Sook;Choi, Jung-Shin
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • pp.123-130
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    • 2006
  • This is a basic study to investigate possibility to application of cohousing model into Korea. Purpose of this study is to grasp respondents' housing value, and its influence on intention to live in cohousing. Research method used for this study was a social survey. Respondents were 214 married people residing in Seoul and its outskirts by accidential sampling. The collected data were analyzed by SPSS 12.0 program using frequency, mean, average, factor analysis, t-test, one-way ANOVA, Duncan's multiple range test, multiple regression and logit analysis. Result of this study was as follows. Housing values were classified into three categories named as individualism oriented housing value, tradition oriented housing value, and economy oriented housing value. Housing values were different by respondents groups. For example, individualism oriented housing value showed difference according to age and housing area. Tradition oriented housing value showed difference according to sex, occupation, and period of residence, while economy oriented housing value showed difference according to number of family members, housing type, and home ownership. In detail, men than women, single-income family than double-income family, and detached house resident than flat resident had higher tradition oriented housing value. The younger than the elder, and Seoul resident than outskirts resident had higher economy oriented housing value. Also home owner than tenant, and the higher tradition oriented group had stronger intention to live in cohousing than others.

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Analysis of Genetic Diversity and Population Structure of Buckwheat (Fagopyrum esculentum Moench) Landraces of Korea Using SSR Markers

  • Song, Jae-Young;Lee, Gi-An;Yoon, Mun-Sup;Ma, Kyung-Ho;Choi, Yu-Mi;Lee, Jung-Ro;Jung, Yeon-Ju;Park, Hong-Jae;Kim, Chung-Kon;Lee, Myung-Chul
    • Korean Journal of Plant Resources
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    • v.24 no.6
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    • pp.702-711
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    • 2011
  • Buckwheat (Fagopyrum esculentum Moench), one of the minor crops grown in Korea belonging to the Polygonaceae family, is an annual crop widely cultivated in Asia, Europe, and America and has a character of outcrossing and self-incompatibility. The objective of this study was to analyze the genetic variability, phylogenetic relationships and population structure of buckwheat landraces of Korea using SSR markers. Ten microsatellite markers have been detected from a total of 79 alleles among the 179 buckwheat accessions were collected from Korea. The number of allele per marker locus ($N_A$) ranged from 2 (GB-FE-001, GB-FE-043 and GB-FE-055) to 31 (GB-FE-035) with an average of 7.9 alleles. GB-FE-035 was the most polymorphic with the highest PIC value 0.93. Major allele frequencies ($M_{AF}$) for the 10 polymorphic loci varied from 0.12 to 0.97 with a mean allele frequency of 0.57. The expected heterozygosity ($H_E$) values ranged from 0.05 to 0.94 with an average of 0.53. The observed heterozygosity ($H_O$) ranged from 0.06 to 0.92 with an average of 0.42. The overall polymorphic information contents (PIC) values ranged from 0.05 to 0.93 with an average of 0.48. The landrace accessions of buckwheat used in the present study were not distinctly grouped according to geographic distribution. The study concludes that the results revealed genetic differentiation was low according to the geographic region because of outcrossing and self-incompatibility. We reported that our analyses on the genetic diversity of common buckwheat cultivars of Korea were performed by using of microsatellite markers.