• Title/Summary/Keyword: nightlight

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Assessment of Human Impact on Mekong River Flood by Using Satellite Nightlight Image

  • Try, Sophal;Lee, Giha;Lee, Daeeop;Thuy, HoangThu
    • Proceedings of the Korea Water Resources Association Conference
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    • 2016.05a
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    • pp.187-187
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    • 2016
  • High intensity of population distribution in deltaic setting especially in Asia tends to have increased and causes coastal flood risk due to lower elevations and significant subsidence. Maximum or peak discharge of flood always causes numerous deaths and huge economic losses. New technology of spatial satellite image has been applied to analyze flood damage. In this research, the relationship of nightlight intensity associated with flood damages has been determined during 1992-2013 with spatial resolution of 30 arc sec ($0.0083^{\circ}$) which is nearly one kilometer at the equator in whole six countries along the Mekong River (i.e., China, Myanmar, Lao PDR, Thailand, Cambodia and Vietnam). ArcGIS Hydrological Flow Length Tool has been used to determine the distance of each pixel areas from the rivers and streams. Statistical analysis results highlight the significant correlation R = 0.47 between nightlight digital number and economic damages per unit area (US$/km2) and R = 0.62 for number of affected people for unit area ($people/km^2$). The areas near by the Mekong River and its tributaries correspond to high flood damage. This spatial analysis result is going to be prestigious key information to the regions and all related stakeholders for decisions and mitigation strategies.

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Application of nightlight satellite imagery for assessing flooding potential area in the Mekong river basin (메콩강 홍수위험분석을 위한 나이트라이트 위성영상 적용성 검토)

  • Try, Sophal;Lee, Daeup;Lee, Giha
    • Journal of Korea Water Resources Association
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    • v.51 no.7
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    • pp.565-574
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    • 2018
  • High population density in deltaic settings, especially in Asia, tends to increase and causes coastal flood risk because of lower elevations and significant subsidence. Large flood annually causes numerous deaths and huge economic losses. In this paper, an innovative technology of spatial satellite imagery has been used as tool to analyze the socio-economic flood-related damage in Mekong river basin. The relationship between nightlight intensity and flood damages has been determined for the period of 1992-2013 with a spatial resolution of 30 arc sec ($0.0083^{\circ}$), which is nearly one kilometer at the equator. Flow path distance was calculated to identify the distance of each cell to river network and to examine how nightlight intensity correlate to the area close to and far from river network. Statistical analysis results highlight the significant correlation between nocturnal luminosity intensity and flood-related damages in countries along the Mekong river (i.e., Cambodia, China, Lao PDR, Thailand, and Vietnam). This result reveals that the areas close to the river network correspond to high human distribution and causes huge damage during flooding. The result may provide key information to the region with respect to decisions, attentions, and mitigation strategies.

A Methodology to Produce Light Pollution Map and Diagnose Urban Nightlight Conditions Using International Space Station Nighttime Image Data (국제 우주정거장 촬영 야간 이미지 데이터를 활용한 빛지도 제작과 빛공해 진단기법)

  • Kim, Jung-A;Cheon, Sang-Hyun
    • The Journal of Korean Institute of Information Technology
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    • v.16 no.12
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    • pp.13-24
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    • 2018
  • Recently, light pollution has become a serious environment issue caused by excessive uses of artificial light. Central and local governments have made efforts to manage light pollution and mitigate light pollution damages. Developing methods to diagnose light pollution is critical to effectively monitor light pollution conditions in Seoul. This study develops a methodology to create a map that presents the status of light pollution in Seoul, using International Space Station(ISS) night-time images. Through the map, we evaluated the areas that show high levels of light intensity and found out local characteristics of light intensity; Commercial area, office building concentrated area, and large sports facilities. The result of study provides basic understanding to present a new way for monitoring light pollution in urban sites.

Analysis of the Status of Light Pollution and its Potential Effect on Ecosystem of the Deogyusan National Park (덕유산국립공원 빛공해 현황 및 빛공해가 공원 생태계에 미치는 잠재적 영향 분석)

  • Sung, Chan Yong;Kim, Young-Jae
    • Korean Journal of Environment and Ecology
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    • v.34 no.1
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    • pp.63-71
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    • 2020
  • This study characterized the spatial and seasonal patterns of light pollution in the Deogyusan National Park and examined the potential effects of light pollution on ecosystems in the park using light intensities derived from VIIRS (Visible Infrared Imaging Radiometer Suite) DNB (Day and Night Band) nightlight images collected in January and August 2018. Results showed that the Muju Deogyusan resort had the greatest light intensity than other sources of light pollution in the park, and light intensity of the resort was much higher in January than in August, suggesting that artificial lights in ski slopes and facilities were the major source of light pollution in the park. An analysis of an urban-natural light pollution gradient along a neighboring urban area through the inside of the park indicated that light radiated from a light pollution source permeated for up to 1km into the adjacent area and contaminated the edge area of the park. Of the legally protected species whose distributions were reported in literature, four mammals (Martes flavigula, Mustela nivalis, Prionailurus bengalensis, Pteromys volans aluco), two birds (Falco subbuteo, Falco tinnunculus), and nine amphibians and reptiles (Onychodactylus koreanus, Hynobius leechii, Karsenia koreana, Rana dybowskii, Rana huanrenensis, Elaphe dione, Rhabdophis tigrinus, Gloydius ussuriensis, Gloydius saxatilis) inhabited light-polluted areas. Of those species inhabiting light-polluted areas, nocturnal species, such as Prionailurus bengalensis and Pteromys volans aluco, in particular, were vulnerable to light pollution. These results implied that protecting ecosystems from light pollution in national parks requires managing nighttime light in the parks and surrounding areas and making a plan to manage nighttime light pollution by taking into account ecological characteristics of wild animals in the parks.