• Title/Summary/Keyword: Spatio-Temporal Distribution

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Spatio-Temporal Analysis of Forest Fire Occurrences during the Dry Season between 1990s and 2000s in South Korea (1990년대와 2000년대 건조계절의 산불발생 시공간 변화 분석)

  • Won, Myoung-Soo;Yoon, Suk-Hee;Koo, Kyo-Sang;Kim, Kyong-Ha
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.3
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    • pp.150-162
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    • 2011
  • For the period between 1991 and 2009, the annual average of 448 forest fires occurred in Korea. Above all, approximately 94% of the total fires frequently occurred during the spring and fall seasons. Therefore, we need to minimize the damage of forest fire and manage them systematically. In this study, we analyzed the spatio-temporal distribution patterns for the frequency of forest fire occurrences by each city and gun during dry season between 1990s and 2000s using GIS. Then we compared to analyze the frequency of forest fire occurrence by ten-day intervals in 2000s with that in 1990s. As a result of analysis, early April showed the highest frequency of forest fire occurrence in both 1990s and 2000s. Compared to the 1990s and 2000s, the regional change of forest fire showed the most frequent fire events around Chungcheong province. Especially extra 27 fires increased in Daejeon city, and the second most frequent fire had more than 10 fires in Jeolla province and Incheon. However, the number of fire frequency decreased by 12 fires at the end of April in Hongcheon-gun(the province of Gangwon). This is the largest drop over the study period. We consider that this paper will utilize usefully to establish regional counterplan for forest fire prevention by understanding regional forest fire patterns from seasonal change.

Spatio-temporal Variations of Marine Environments and Phytoplankton Community in the Gochang Coastal Waters (GCW) of Southern West Sea in Korea (서해 남부, 고창연안해역의 해양환경 및 식물플랑크톤 군집의 시·공간 변동특성)

  • Yoon, Yang Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.11
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    • pp.477-493
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    • 2020
  • This study conducted a seasonal survey to analyze the spatio-temporal variations of marine environments and phytoplankton community in Gochang Coastal Waters (GCW) from August 2016 to April 2017. In the results, the water temperature ranged from 2.1℃ to 34.5℃, showing a large seasonal variation, but the salinity changed from 31.14 psu to 32.64 psu. Therefore, the seasonal variations of water types in GCW were mainly determined by water temperature. The phytoplankton community consisted of 53 genera and 86 species, showing a relatively simple distribution. The phytoplankton cell density ranged from 2.2 to 689.2 cells mL-1, with an average of 577.2 cells mL-1, which was low in autumn and high in winter. The seasonal succession of phytoplankton dominant species was mainly diatoms during the whole year, Leptocylindrus danicus, Chaetoceros curvisetus, Skeletonema costatum-ls in summer, Paralia sulcata, Eucampia zodiacus in autumn, S. costatum-ls, Thalassiosira nordenskioeldii in winter, and S. costatum-ls, Asterionella glacialis in spring. In other words, the phytoplankton community showed high diversity in GCW throughout the year. According to the PCA, GCW were easily heated and cooled by radiant energy at lower depth, and the seasonal distributions of phytoplankton were determined by the supply of nutrients by re-fuelling of surface sediments due to the seawater mixing such as tidal mixing.

Spatio-Temporal Changes and Characteristics of Households Failing to Meet the New Minimum Housing Standard in Seoul Metropolitan(1995~2010) (서울시 최저주거기준 미달가구의 시.공간적 특성과 변화(1995~2010년))

  • Kim, Yongchang;Choi, Eunyoung
    • Journal of the Korean Geographical Society
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    • v.48 no.4
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    • pp.509-532
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    • 2013
  • Minimum Housing Standard is an instrument to cope with the problems of public health and community hygiene, deterioration of working class housing conditions appeared commonly in the process of capitalist industrialization and rapid rural-to-urban migration. This paper aims to examine the institutionalization of histories of minimum housing standard in the advanced countries, and analyze the spatio-temporal changes and characteristics of households failing to meet the New Minimum Housing Standard in Seoul Metropolitan since 1995. The analysis of this paper is based on the census data on population and housing. The results are as follows; Households failing to meet the New Minimum Housing Standard in Seoul are 501,000 households(1.368 million person, 14.4%). This means Seoul has overtaken the national average 11.8% for the first time and there are structurally marginal band of households who can not improve the housing conditions by themselves. In addition, the fact that the rate of Seoul households living in the marginal shelter including the basement and rooftop room is the highest in Korea means the housing quality issues of Seoul is serious. Spatial distribution of households failing to meet the standard is divided into the northeast area and the southwest area in Seoul. Main features of the households are female-headed families, middle and old-aged people, divorce families, lower educated people, under and graduate students, non-apartments, dweller in 15~20 year old houses.

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Spatio-temporal Distributions of Polychaete Communities and Benthic Environmental Characteristics of the Harbor Area of Busan Port, Korea (부산항 주변 저서다모류군집의 시.공간 분포와 저서환경의 특징)

  • Jung, Rae-Hong;Yoon, Sang-Pil;Kim, Youn-Jung;Choi, Min-Kyu;Lee, Won-Chan
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.16 no.3
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    • pp.125-138
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    • 2011
  • This study was conducted to investigate the benthic condition around Busan Port by analysing spatio-temporal distribution pattern of polychaete community and some benthic environmental factors. Field survey was seasonally carried out at 15 stations covering in and outside of Busan Port from February to December, 2007. Water temperature, salinity and the type of surface sediment showed little changes among the stations, but factors related to organic enrichment such as TOC, AVS, coprostanol showed an obvious contrast, especially between in and outside of Busan Port. A total of96 species occurred and mean density was 1,814 ind./$m^2$. Species richness was higher at outer port than inner port, but density was higher at inner port. Dominant species were Aphelochaeta monilaris, Magelona japonica, Pseudopolydora paucibranchiata, etc. and many of them were typical species of organically enriched area. From the multivariate analyses, the whole study area was composed of two distinct polychaete communities located at the inside and outside of the port, and seasonal changes didn't have any influential effects on the structure. Coprostanol and AVS, indicators of organically enriched condition, well explained the community structures of polychaete worms in the vicinity of Busan Port. In this context, the innermost area of North Harbor was in a highly enriched state.

Analysis of Spatio-Temporal Patterns of Nighttime Light Brightness of Seoul Metropolitan Area using VIIRS-DNB Data (VIIRS-DNB 데이터를 이용한 수도권 야간 빛 강도의 시·공간 패턴 분석)

  • Zhu, Lei;Cho, Daeheon;Lee, Soyoung
    • Journal of Cadastre & Land InformatiX
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    • v.47 no.2
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    • pp.19-37
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    • 2017
  • Visible Infrared Imaging Radiometer Suite Day-Night Band (VIIRS-DNB) data provides a much higher capability for observing and quantifying nighttime light (NTL) brightness in comparison with Defense Meteorological Satellite-Operational Linescan System (DMSP-OLS) data. In South Korea, there is little research on the detection of NTL brightness change using VIIRS-DNB data. This study analyzed the spatial distribution and change of NTL brightness between 2013 and 2016 using VIIRS-DNB data, and detected its spatial relation with possible influencing factors using regression models. The intra-year seasonality of NTL brightness in 2016 was also studied by analyzing the deviation and change clusters, as well as the influencing factors. Results are as follows: 1) The higher value of NTL brightness in 2013 and 2016 is concentrated in Seoul and its surrounding cities, which positively correlated with population density and residential areas, economic land use, and other factors; 2) There is a decreasing trend of NTL brightness from 2013 to 2016, which is obvious in Seoul, with the change of population density and area of industrial buildings as the main influencing factors; 3) Areas in Seoul, and some surrounding areas have high deviation of the intra-year NTL brightness, and 71% of the total areas have their highest NTL brightness in January, February, October, November and December; and 4) Change of NTL brightness between summer and winter demonstrated a significantly positive relation with snow cover area change, and a slightly and significantly negative relation with albedo change.

Spatio-temporal Variability and Size Fractionation of Chlorophyll a in the Jeju Marine Ranching Area(JMRA) with Special Reference to the Signification of Nanoplankton (제주 바다목장 해역 크기별 엽록소 a의 시·공간적 분포 특성과 미소플랑크톤의 중요성)

  • Yoon, Yang Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.6388-6398
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    • 2014
  • To understand size fractioned chlorophyll a and material cycle characteristics in Jeju marine ranching area (JMRA), 4 times of survey were conducted from April to November 2008. Picoplankton on the surface in JMRA was on average, $0.30{\mu}g/L$(annual mean(M):17.3%) in the $0.03{\sim}0.84{\mu}g/L$ range, accounting for 17.3%. Nannoplankton and picoplankton was on average, $1.35{\mu}g/L$(M:78.0%) in the $0.22{\sim}3.93{\mu}g/L$ range, and $1.73{\mu}g/L$(M:4.7%) in the nd ~ 0.24 range, respectively. The 10m layer was similar to the surface. The measured values changed according to the measurement times but the nanoplankton composition ratio was higher throughout the year. In addition, the size fractioned chlorophyll a distribution in JMRA was similar to that of tropical sea area affected by the Monsoon rather than South Korean offshore coast geographically adjacent to the East China Sea and Japan coastal waters affected by the Kuroshio/Tsushima warm currents. That is, the material cycle of JMRA consists of a microbial food web rather than traditional food chain at a lower trophic levels. Primary production is deemed to have a higher possibility of being adjusted by top-down dynamics, such as micro-zooplankton grazing pressure rather than nutrients supply.

Research on the Spatio-temporal Distribution Pattern of Temperature Using GIS in Korea Peninsular (GIS를 이용한 한반도 기온의 시·공간적 분포패턴에 관한 연구)

  • KIM, Nam-Shin
    • Journal of The Geomorphological Association of Korea
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    • v.15 no.2
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    • pp.85-94
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    • 2008
  • This study is to construe spatio-temporal characteristics of temperature in cities and changes of climatical regions in analyzing a change of Korea Peninsular climate. We used daily mean air temperature data which was collected in South and North Korea for the past 34 years from 1974 to 2007. We created temperature map of 500m resolution using Inverse Distance Weight in application with adiabatic lapse rate per month in linear relation with height and temperature. In the urbanization area, the data analyzed population in comparison with temperature changes by the year. An annual rising rate of temperature was calculated $0.0056^{\circ}C$, and the temperature was increased $2.14^{\circ}C$ from 1974 to 2107. The south climate region in Korea by the Warmth index was expanded to the middle climate region by the latitude after 1990s. A rise of urban area in mean temperature was $0.5-1.2^{\circ}C$, Seoul, metropolitan and cities which were high density of urbanization and industrialization with the population increase between 1980s and 1990s. In case of North Korea, Cities were Pyeongyang, Anju, Gaecheon, Hesan. A rise in cities areas in mean temperature has influence on vegetation, especially secondary growth such as winter buds of pine trees appears built-up area and outskirts in late Autumn. Finally, nowaday we confront diverse natural events over climatical changes, We need a long-term research to survey and analyze an index on the climatical changes to present a systematic approach and solution in the future.

Characteristics of the spatio-temporal distributions of water quality and phytoplankton communities in the Isa Stream systems (ISS) (이사천 수계의 수질환경과 식물플랑크톤 군집의 시·공간적 분포 특성)

  • Park, Jong Sick;Cheong, Cheong-Jo;Yoon, Yang Ho
    • Korean Journal of Environmental Biology
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    • v.39 no.3
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    • pp.273-288
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    • 2021
  • We analyzed the spatio-temporal distribution characteristics of water quality and phytoplankton communities in the Isa Stream systems (ISS) from Sangsa Lake to Suncheon Bay. Sangsa Lake showed relatively oligotrophic and mesotrophic conditions, but the freshwater and mixed brackish water zones showed more severe eutrophication than Sangsa Lake and Suncheon Bay due to the influence of industrial waste such as livestock waste. In terms of the phytoplankton community, the number of phytoplankton species was higher in freshwater and mixed brackish water zones than in Sangsa Lake and Suncheon Bay, but the cell density and Chlorophyll-a concentrations (Chl-a) were relatively high in Sanga Lake and Suncheon Bay. In particular, the mesotrophic species Fragilaria crotonensis and Asterionella formosa showed different dominance in the surface and bottom layers, and the influence of A. formosa was significant in the freshwater and mixed brackish water zones in spring and summer. However, Skeletonema costatum-ls, a eutrophic indicator species, dominated in mixed brackish water zones to seawater in autumn and winter. Thus, the severe eutrophication and rapid environmental changes in the ISS could seriously damage the coastal ecosystem in Suncheon Bay. These ecosystem changes are threatening in terms of conservation and management of the UNESCO Suncheon Biosphere Reserve and Yeoja Bay including Suncheon Bay, which recorded the first Ramsar wetland in Korea. Therefore, further research is needed to establish an in-depth management plan.

Deployment Strategy of ARGO Floats in the East Sea (동해 ARGO 플로트의 투하 전략)

  • Park, Jong Jin;Park, Jong Sook
    • Ocean and Polar Research
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    • v.37 no.3
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    • pp.179-188
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    • 2015
  • This study was carried out to determine the optimal number of ARGO floats in the East Sea in order to maximize their applications. The dominant spatio-temporal scale, size of the domain, and the typical float lifetimes in the East Sea were taken into consideration. The mean spatial de-correlation scale of temperature on isobaric surfaces reaches about 60 km. The minimum necessary number of floats is about 82 on average in order to secure independent ARGO profiles with the de-correlation scale. Considering the float lifetimes, about 27 floats per year should be deployed to maintain the 82 ARGO float array every year. To obtain spatially uniform distribution of ARGO float data, mean residence time and dispersion rate (basin area/residence time) of ARGO floats were evaluated in each basin of the East Sea. A faster (slower) dispersion rate requires more (less) ARGO floats to maintain the spatially uniform number of floats. According to the analysis, it is likely that the optimal ratio of the number of floats for each basin is 1:2:4 corresponding to Ulleung Basin:Yamato Basin:Japan Basin. In order to maintain relatively uniform ARGO observing networks, it is necessary to establish a long-term plan for deployment strategy based on float pathways and the dispersion rate parameters estimated by using currently active ARGO float trajectory data as well as reanalysis data.

Spatio-temporal Distribution of Downward Shortwave Radiation using MODIS Satellite Imagery (MODIS 위성 이미지를 이용한 태양 복사 에너지의 시공간 분포 특성)

  • Choi, Minha;Hwang, Kyotaek;Kim, Hyun Woo
    • 한국방재학회:학술대회논문집
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    • 2011.02a
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    • pp.106-106
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    • 2011
  • 지표면으로 입사하는 태양 복사 에너지를 정확하게 산출하는 것은 에너지 수지 방법을 이용한 유역 분석의 신뢰도를 높이는데 기여할 수 있다. 태양 복사 에너지는 지형 인자와 대기 인자를 이용하여 산정할 수 있으나 기상관측장비 특성상 지점값 위주의 연구가 이루어지고 있다. 본 연구에서는 이러한 공간적 제약을 완화하기 위해 원격탐사 기법을 이용하여 지표면에 들어오는 태양 복사 에너지를 산출하고자 하였다. 시간, 공간적으로 중규모 해상도를 가지고 있는 Moderate Resolution Imaging Spectroradiometer(MODIS) 위성 관측 이미지를 이용하여 태양 복사 에너지의 시공간 분포를 산정하고 그 결과를 연구 지역인 광릉/해남 KoFlux site의 지상 관측값을 이용하여 검증함으로써 산정 모형의 국내 적용성을 확인하였다. 비교적 적은 수의 인자를 필요로 하는 Allen et al.(2007) 태양 복사 에너지 산정 모형과 36가지의 서로 다른 파장 이미지를 이용하여 산출된 MODIS 대기 자료를 이용하여 결과를 산정함으로써 모형의 간편성 및 효율성을 확인할 수 있었다. 특히 광릉/해남 KoFlux site 관측치와 모형 산정값과의 상관계수가 각각 0.95, 0.96으로 매우 높은 값을 가짐으로써 모형의 높은 신뢰성을 검토하였다. 향후 연구의 결과로써 얻어진 태양 복사 에너지의 시공간 분포특성 분석을 통해 에너지 수지 방법의 정확성을 향상시키고자 한다.

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