• Title/Summary/Keyword: land surface

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Regional Scale Evapotranspiration Mapping using Landsat 7 ETM+ Land Surface Temperature and NDVI Space (Landsat ETM+영상의 지표면온도와 NDVI 공간을 이용한 광역 증발산량의 도면화)

  • Na, Sang-Il;Park, Jong-Hwa
    • Journal of The Korean Society of Agricultural Engineers
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    • v.50 no.3
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    • pp.115-123
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    • 2008
  • Evapotranspiration mapping using both meteorological ground-based measurements and satellite-derived information has been widely studied during the last few decades and various methods have been developed for this purpose. It is significant and necessary to estimate regional evapotranspiration (ET) distribution in the hydrology and water resource research. The study focused on analyzing the surface ET of Chungbuk region using Landsat 7 ETM imagery. For this process, we estimated the regional daily evapotranspiration on May 8, 2000. The estimation of surface evapotranspiration is based on the relationship between Temperature Vegetation Dryness Index (TVDI) and Morton's actual ET. TVDI is the relational expression between Normalized Difference of Vegetation Index (NDVI) and Land Surface Temperature (LST). The distribution of NDVI corresponds well with that of land-use/land cover in Chungbuk. The LST of several part of city in Chungbuk region is higher in comparison with the averaged LST. And TVDI corresponds too well with that of land cover/land use in Chungbuk region. The low evapotranspiration availability is distinguished over the large city like Cheongju-si, Chungju-si and the difference of evapotranspiration availability on forest and paddy is high.

Comparison of Land Surface Temperatures Derived from Surface Emissivity with Urban Heat Island Effect (지표 방사율에 의한 지표온도와 도시열섬효과 비교)

  • Jeong, Jong-Chul
    • Journal of Environmental Impact Assessment
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    • v.18 no.4
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    • pp.219-227
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    • 2009
  • Because of urban development and changed land cover types, It is very important to acquire pixel unit of land surface temperature(LST) information when the heat island effect(HIE) of regional area are investigated. The brightness temperature observed by satellite is very useful for assessing the pixel unit of LST distributions for the analysis of thermal environment problems of urban areas. Also, satellite land cover data are very useful to our understanding of surface conditions of study areas. In this study, brightness temperature information of Landsat TM thermal channel was analyzed and compared with land cover information of Jeon-ju city. The atmospheric correction of TM thermal channel carried out to explain for compared LST long term monitoring errors. However, simple estimation and evaluation methods to find a physical relationship between LST from satellite images and in-situ data are compared with reference channel emissivity.

The Relationship among Land Use, Vegetation and Surface Temperature in Urban Areas -The Case of Deagu City- (도시지역 지표온도와 토지이용 및 식생상태와의 상관관계에 관한 연구 : 대구광역시의 경우)

  • Kim, Jae Ik;Yeo, Chang-Hwan
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.2
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    • pp.21-30
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    • 2005
  • The primary purpose of this paper is to prove a clear relationship among land use type, vegetation level and surface temperature. For this purpose, this paper presents series of spatial distribution maps of the three features obtained through the visual interpretation of digital images. The result of study tells us that the spatial distribution of the vegetation level is very similar with that of surface temperature. By analyzing the relationship between surface temperature and land use types, this study categorizes the eighteen urban land uses into 7-8 groups according to their average surface temperature. The Duncan test was conducted to categorize the land uses. The surface temperature of manufacturing related land use is the highest, semi-residential use is the next, non-residential land use is the next to the lowest, and the agricultural and forest land use is the lowest. This paper provides another strong evidence of the relationship by showing the regression result.

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A Study on the Accuracy Improvement of Land Surface Temperature Extraction by Remote Sensing Data (원격탐사 자료에 의한 지표온도추출 정확도 향상에 관한 연구)

  • Um, Dae-Yong
    • Journal of the Korean Association of Geographic Information Studies
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    • v.9 no.2
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    • pp.159-172
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    • 2006
  • In this study, the series of Landsat TM/ETM+ images was acquired to extract land surface temperature for wide-area and executed geometric correction and radiometric correction. And the land surface temperature was extracted using NASA Model, and achieved the first correction by performing land coverage category for study area and applied characteristic emission rate. Land surface temperature which was acquired by the first correction was analyzed in correlation with Meteorological Administration's temperature data by regression analysis, and established correction formula. And I wished to improve accuracy of land surface temperature extraction using satellite image by second correcting deviations between two data using establishing correction formula. As a result, land surface temperature acquired by 1st and 2st correction could be corrected in mean deviation of about ${\pm}3.0^{\circ}C$ with Meteorological Administration data. Also, I could acquire land surface temperature about study area by higher accuracy by applying to other Landsat images for re-verification of study results.

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Prediction of Land Surface Temperature by Land Cover Type in Urban Area (도시지역에서 토지피복 유형별 지표면 온도 예측 분석)

  • Kim, Geunhan
    • Korean Journal of Remote Sensing
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    • v.37 no.6_3
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    • pp.1975-1984
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    • 2021
  • Urban expansion results in raising the temperature in the city, which can cause social, economic and physical damage. In order to prevent the urban heat island and reduce the urban land surface temperature, it is important to quantify the cooling effect of the features of the urban space. Therefore, in order to understand the relationship between each object of land cover and the land surface temperature in Seoul, the land cover map was classified into 6 classes. And the correlation and multiple regression analysis between land surface temperature and the area of objects, perimeter/area, and normalized difference vegetation index was analyzed. As a result of the analysis, the normalized difference vegetation index showed a high correlation with the land surface temperature. Also, in multiple regression analysis, the normalized difference vegetation index exerted a higher influence on the land surface temperature prediction than other coefficients. However, the explanatory power of the derived models as a result of multiple regression analysis was low. In the future, if continuous monitoring is performed using high-resolution MIR Image from KOMPSAT-3A, it will be possible to improve the explanatory power of the model. By utilizing the relationship between such various land cover types considering vegetation vitality of green areas with that of land surface temperature within urban spaces for urban planning, it is expected to contribute in reducing the land surface temperature in urban spaces.

Characteristics on Land-Surface and Soil Models Coupled in Mesoscale Meteorological Models (중규모 기상모델에 결합된 육지표면 및 토양 과정 모델들의 특성)

  • Park, Seon K.;Lee, Eunhee
    • Atmosphere
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    • v.15 no.1
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    • pp.1-16
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    • 2005
  • Land-surface and soil processes significantly affect mesoscale local weather systems as well as global/regional climate. In this study, characteristics of land-surface models (LSMs) and soil models (SMs) that are frequently coupled into mesoscale meteorological models are investigated. In addition, detailed analyses on three LSMs, employed by the PSU/NCAR MM5, are provided. Some impacts of LSMs on heavy rainfall prediction are also discussed.

Extraction of Land Surface Change Information by Using Landsat TM Images (Landsat TM 영상을 이용한 지표변화정보 추출)

  • 최승필;양인태
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.3
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    • pp.261-267
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    • 2003
  • We are able to simultaneously extract the land surface change information, as we input each information extracted from images classified during the two periods, as the attribute information of geographic information, and then use it a parameter of GIS. Hence, this research sought to present basic data far efficient management and development of land surface, together with land use trends, by using the remote-sensing technique enabling the acquisition of the land surface covering information, as well as the benefits of GIS. The research conducted a study on the extraction of land surface change information, and made it possible to treat image information easily compared to the existing image classification methods, thereby making it easy to know the land surface change process for each pixel.

Review of the Role of Land Surface in Global Climate Change (기후변화에서 지표환경의 역할에 대한 고찰)

  • Kim, Seong-Joong
    • The Korean Journal of Quaternary Research
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    • v.23 no.1
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    • pp.42-53
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    • 2009
  • In response to the abrupt climate change in recent years, atmosphere, ocean and cryosphere are reported to be altered. In addition to these changes, the land surface is also gradually changing and its impact on the global climate may not be negligible. The land surface change impacts the global climate via two ways, the biogeochemical and biophysical feedbacks. The biogeochemcial change in the land surface modifies the atmospheric trace-gas concentrations through a change in photo synthesis, while biophycal changes of the land surface alters the surface albedo, which influences the amount of the short wave radiative heat fluxes. There are many examples in the past that the change in land surface greatly influences the global climate change. The recent IPCC report has suggested that the climate change will occur rather abrubtly in the near future. In order to predict the future climate accurately, the impact of the land surface change is fully considered.

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Identification of the Anthropogenic Land Surface Temperature Distribution by Land Use Using Satellite Images: A Case Study for Seoul, Korea

  • Bhang, Kon Joon;Lee, Jin-Duk
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.4
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    • pp.249-260
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    • 2017
  • UHI (Urban Heat Island) is an important environmental issue occurring in highly developed (or urbanized) area such as Seoul Metropolitan City of Korea due to modification of the land surface by man-made structures. With the advance of the remote sensing technique, land cover types and LST (Land Surface Temperature) influencing UHI were frequently investigated describing that they have a positive relationship. However, the concept of land cover considers material characteristics of the urban cover in a comprehensive way and does not provide information on how human activities influence on LST in detail. Instead, land use reflects ways of land use management and human life patterns and behaviors, and explains the relationship with human activities in more details. Using this concept, LST was segmented according to land use types from the Landsat imagery to identify the human-induced heat from the surface and interannual and seasonal variation of LST with GIS. The result showed that the LST intensity of Seoul was greatest in the industrial area and followed by the commercial and residential areas. In terms of size, the residential area could be defined as the major contributor among six urban land use types (i.e., residential, industrial, commercial, transportation, etc.) affecting UHI during daytime in Seoul. For temperature, the industrial area was highest and could be defined as a major contributor. It was found that land use type was more appropriate to understand the human-induced effect on LST rather than land cover. Also, there was no significant change in the interannual pattern of LST in Seoul but the seasonal difference provided a trigger that the human life pattern could be identified from the satellite-derived LST.

A New Forest Fire Detection Algorithm using Outlier Detection Method on Regression Analysis between Surface temperature and NDVI

  • Huh, Yong;Byun, Young-Gi;Son, Jeong-Hoon;Yu, Ki-Yun;Kim, Yong-Il
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.574-577
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    • 2006
  • In this paper, we developed a forest fire detection algorithm which uses a regression function between NDVI and land surface temperature. Previous detection algorithms use the land surface temperature as a main factor to discriminate fire pixels from non-fire pixels. These algorithms assume that the surface temperatures of non-fire pixels are intrinsically analogous and obey Gaussian normal distribution, regardless of land surface types and conditions. And the temperature thresholds for detecting fire pixels are derived from the statistical distribution of non-fire pixels’ temperature using heuristic methods. This assumption makes the temperature distribution of non-fire pixels very diverse and sometimes slightly overlapped with that of fire pixel. So, sometimes there occur omission errors in the cases of small fires. To ease such problem somewhat, we separated non-fire pixels into each land cover type by clustering algorithm and calculated the residuals between the temperature of a pixel under examination whether fire pixel or not and estimated temperature of the pixel using the linear regression between surface temperature and NDVI. As a result, this algorithm could modify the temperature threshold considering land types and conditions and showed improved detection accuracy.

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