• Title/Summary/Keyword: EVI

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Analysis of Vulnerable Regions of Forest Ecosystemin the National Parks based on Remotely-sensed Data (원격탐사자료에 기초한 국립공원 산림 생태계의 취약지역 분석)

  • Choi, Chul-Hyun;Koo, Kyung-Ah;Kim, Jinhee
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.19 no.5
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    • pp.29-45
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    • 2016
  • This study identified vulnerable regions in the national parks of the Republic of Korea (ROK). The potential vulnerable regions were defined as areas showing a decline in forest productivity, low resilience, and high sensitivity to climate variations. Those regions were analyzed with a regression model and trend analysis using the Enhanced Vegetation Index (EVI) data obtained from long-term observed Moderate Resolution Imaging Spectroradiometer (MODIS) and gridded meteorological data. Results showed the area with the highest vulnerability was Naejangsan National Park in the southern part of ROK where 32.5% ($26.0km^2$) of the total area was vulnerable. This result will be useful information for future conservation planning of forest ecosystem in ROK under environmental changes, especially climate change.

The Impact of Environmental Health Factors on Extreme-heat Vulnerability Assessment in a Metropolitan City (환경보건적 요소가 도시 내 폭염 취약성 평가 결과에 미치는 영향 분석)

  • Lee, Won-Jung;Kang, Jae-Eun;Kim, Yoo-Keun
    • Journal of Environmental Health Sciences
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    • v.39 no.6
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    • pp.492-504
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    • 2013
  • Objectives: This analysis seeks to evaluate the impact of environmental health factors (EHF; e.g. hospital beds per capita, employees of medical institutions) on extreme-heat vulnerability assessment in Busan Metropolitan City during 2006-2010. Methods: According to the vulnerability concept suggested by the Intergovernmental Panel on Climate Change (IPCC), extreme-heat vulnerability is comprised of the categories of Exposure, Sensitivity, and Adaptive Capacity (including EHF). The indexes of the Exposure and Sensitivity categories indicate positive effects, while the Adaptive capacity index indicates a negative effect on extreme-heat vulnerability. Variables of each category were standardized by the re-scaling method, and then each regional relative vulnerability was computed with the vulnerability index calculation formula. Results: The extreme-heat vulnerability index (EVI) excepting EHF was much higher in urban areas than in suburban areas within the metropolitan area. When EHF was considered, the difference in the EVI between the two areas was reduced due to the increase of the Adaptive capacity index in urban areas. The low EVI in suburban areas was induced by a dominant effect of natural environmental factors (e.g. green area) within the Adaptive capacity category. Conclusions: To reduce the vulnerability to extreme heat in urban areas, which were more frequently exposed to extreme heat than others areas, public health and natural environments need to be improved in sensitive areas.

Analysis of 2012 Spring Drought Using Meteorological and Hydrological Drought Indices and Satellite-based Vegetation Indices (기상 및 수문학적 가뭄지수와 위성 식생지수를 활용한 2012년 봄 가뭄 분석)

  • Ahn, So-Ra;Lee, Jun-Woo;Kim, Seong-Joon
    • KCID journal
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    • v.21 no.1
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    • pp.78-88
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    • 2014
  • This study is to analyze the 2012 spring drought of Korea using drought index and satellite image. The severe spring drought recorded in May of 2012 showed 36.4% of normal rainfall(99.5mm). The areas of west part of Gyeonggi-do and Chungcheong-do were particularly serious. The drought indices both the SPI(Standardized Precipitation Index) and WADI(WAter supply Drought Index) represented the drought areas from the end of May and to the severe drought at the end of June. The drought by SPI completely ended at the middle of July, but the drought by WADI continued severe drought in the agricultural reservoir watersheds of whole country even to the end of the July. On the other hand, the results by spatial NDVI(Normalized Difference Vegetation Index) and EVI(Enhanced Vegetation Index) data from Terra MODIS, both indices showed relatively low values around the areas of Sinuiju, Pyongyang, and west coast of North Korea and Gyeonggi-do and Chungcheong-do of South Korea indicating drought condition. Especially, the values of NDVI and EVI at Chungcheong-do were critically low in June compared to the normal year value.

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Surface Emissivity Derived From Satellite Observations: Drought Index

  • Yoo, Jung-Moon;Yoo, Hye-Lim
    • Journal of the Korean earth science society
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    • v.27 no.7
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    • pp.787-803
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    • 2006
  • The drought index has been developed, based on a $8.6{\mu}m$ surface emissivity in the $8-12{\mu}m$ MODIS channels over the African Sahel region (10-20 N, 13 W-35 W) and the Seoul Metropolitan Area (SMA: 37.2-37.7 N, 126.6-127.2 E). The emissivity indicates the $SiO_2$ strength and can vary interannually by vegetation, water vapor, and soil moisture, as a potential indicator of drought conditions. In a well-vegetated region close to 10 N of the Sahel, the Normalized Difference Vegetation Index (NDVI) showed high sensitivity, while the emissivity did not. On the other hand, the NDVI experienced negligible variability in a poorly vegetated region near 20 N, while the emissivity reflected sensitively the effects of atmospheric water vapor and soil moisture conditions. Seasonal variations of the emissivity (0.94-0.97) have been examined over the SMA during the 2003-2004 period compared to NDVI (or Enhanced Vegetation Index; EVI). Here, the dryness was more severe in urban area with less vegetation than in suburban area; the two areas corresponded to the north and south of the Han river, respectively. The emissivity exhibiting a significant spatial correlation of ${\sim}0.8$ with the two indices can supplement their information.

A Study of River Flood Area Informationization Technique Using RS and GIS (RS/GIS를 이용한 하천 침수 지역 정보화 기법 연구)

  • Shin, Hyung-Jin;Chae, Hyo-Sok;Hwang, Eui-Ho;Park, Jae-Yong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.256-256
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    • 2012
  • 2011년 태국 차오프라야 강 유역($160,813km^2$)에서 발생한 홍수에 의해 많은 피해가 발생했다. 태국 홍수는 2011년 7월 말부터 3개월간 내린 집중호우로 중부지방에 50년 만에 최악의 자연재해를 맞이하였다. 태국 북쪽 지역에서 난 강과 핑 강의 범람을 시작으로 태국 중앙 지역을 흐르는 차오프라야 강의 수위는 상류의 홍수가 하류로 내려옴에 따라 범람하여 수도 방콕까지 침수되었다. 본 연구에서는 홍수범람시 시공간적 침수상황이 파악 가능한 Terra MODIS (Moderate Resolution Imaging Spectroradiometer) 영상을 이용하여 태국 차오프라야 강 유역의 홍수에 의한 침수지역을 추정하고자 하였다. 2011년 7월 29일에서 2012년 1월 9일까지의 500 m 해상도인 MODIS product MOD09 (Surface Reflectance) 8일 합성 영상을 수집하고 식생지수 (EVI; Enhanced Vegetation Index), 지표수분지수 (LSWI; Land Surface Water Index))와 DVEL지수 (Difference Value between EVI and LSWI)를 이용하여 홍수범람 지역과 수역관련지역을 정보화 기법을 제시하였다. 본 연구의 결과는 홍수 범람지역의 자료를 정보화하고 그 결과를 정량적으로 제시하는 방법으로 활용될 수 있으며, MODIS 자료의 이용은 시공간적 하천 홍수범람지역 탐지의 가능성을 알 수 있었다.

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High-Resolution Sentinel-2 Imagery Correction Using BRDF Ensemble Model (BRDF 앙상블 모델을 이용한 고해상도 Sentinel-2 영상 보정)

  • Hyun-Dong Moon;Bo-Kyeong Kim;Kyeong-Min Kim;Subin Choi;Euni Jo;Hoyong Ahn;Jae-Hyun Ryu;Sung-Won Choi;Jaeil Cho
    • Korean Journal of Remote Sensing
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    • v.39 no.6_1
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    • pp.1427-1435
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    • 2023
  • Vegetation indices based on selected wavelength reflectance measurements are used to represent crop growth and physiological conditions. However, the anisotropic properties of the crop canopy surface can govern spectral reflectance and vegetation indices. In this study, we applied an ensemble of bidirectional reflectance distribution function (BRDF) models to high-resolution Sentinel-2 satellite imagery and compared the differences between correction results before and after reflectance. In the red and near-infrared (NIR) band reflectance images, BRDF-corrected outlier values appeared in certain urban and paddy fields of farmland areas and forest shadow areas. These effects were equally observed when calculating the normalized difference vegetation index (NDVI) and 2-band enhanced vegetation index (EVI2). Furthermore, the outlier values in corrected NIR band were shown in pixels shadowed by mountain terrain. These results are expected to contribute to the development and improvement of BRDF models in high-resolution satellite images.

COMMON FIXED POINT THEOREMS FOR MAPPINGS ON CONE METRIC SPACES

  • Kim, Jeong-Jin;Bae, Jong-Sook;Cho, Seong-Hoon
    • Journal of applied mathematics & informatics
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    • v.30 no.5_6
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    • pp.1067-1075
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    • 2012
  • In this paper we generalize the results of Ili$\acute{c}$ and Rako$\check{c}$evi$\acute{c}$. Also, we generalize one of Berinde's results to cone metric spaces. And we introduce the notion of compatible mappings of type (BC), and we establish a common fixed point theorem for these mappings.

Predicting Future Terrestrial Vegetation Productivity Using PLS Regression (PLS 회귀분석을 이용한 미래 육상 식생의 생산성 예측)

  • CHOI, Chul-Hyun;PARK, Kyung-Hun;JUNG, Sung-Gwan
    • Journal of the Korean Association of Geographic Information Studies
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    • v.20 no.1
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    • pp.42-55
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    • 2017
  • Since the phases and patterns of the climate adaptability of vegetation can greatly differ from region to region, an intensive pixel scale approach is required. In this study, Partial Least Squares (PLS) regression on satellite image-based vegetation index is conducted for to assess the effect of climate factors on vegetation productivity and to predict future productivity of forests vegetation in South Korea. The results indicate that the mean temperature of wettest quarter (Bio8), mean temperature of driest quarter (Bio9), and precipitation of driest month (Bio14) showed higher influence on vegetation productivity. The predicted 2050 EVI in future climate change scenario have declined on average, especially in high elevation zone. The results of this study can be used in productivity monitoring of climate-sensitive vegetation and estimation of changes in forest carbon storage under climate change.