• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.4
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• pp.145-157
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• 2015

In 2015, drought was at the worst stage of devastation in Soyanggang Dam watershed. The purpose of this study is to trace the drought area around Soyanggang dam watershed by using Terra MODIS image because it has the ability of spatio-temporal dynamics. The MODIS indices, which included the enhanced vegetation index (NDVI), were extracted from MODIS product MOD13 16-day composite datasets with a spatial resolution of 250m from 2010.01.01 to 2015.06.30. We found that application of Vegetation Condition Index (VCI) and Standardized Vegetation Index (SVI) was suitable for monitoring the drought area. The result can be used to acquire the drought data scattered and demonstrate the potential for the use of MODIS data for temporal and spatial detection of drought effects.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.3
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• pp.140-152
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• 2017

The Korea Meteorological Administration (KMA) regularly publishes various drought indices. However, most of these are meteorological drought indices that are not only difficult but often inappropriate to apply to agriculture. In this study, the meteorological drought index and the agricultural drought index were calculated for the representative points of South Korea during the same period, and the differences in geographical distribution were analyzed according to the characteristics of drought. Although the overall drought patterns estimated by multiple drought indices were similar, the differences were also confirmed due to the different simulation methods depending on the character of drought. Especially, agricultural drought index (ADI) showed higher accuracy in the agricultural sector than that of meteorological drought index (e.g., SPI, PN). In addition, the drought patterns in recent years analyzed by ADI were more severe in spring and early summer compared with normal year. In autumn and winter, drought was weaker than normal year. For the recent periods, inland areas had more droughts than coastal areas. Considering the specific drought indices for the individual sectors, it will be helpful to take measures against drought according to the individual characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.517-526
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• 2018

As groundwater recharge shows the heterogeneity in space and time due to land use and soil types, estimating daily recharge by integrated hydrologic analysis is needed. In this work, the SWAT-MODFLOW model was applied to compute daily based groundwater recharge in Jangseong region. The accuracy of the model was evaluated by comparing the observed and calculated values of the unsteady groundwater flow levels after calibrating the observed and calculated flow rates of the stream for a hydrological analysis. The estimated hydrologic components showed a strong correlation with each other and significant spatial variations regarding the groundwater recharge rate in accordance with the heterogeneous watershed characteristics such as subbasin slope, land use, and soil type. Overall, it was concluded that the coupled hydrologic models were capable of simulating the spatial variation with respect to the hydrologic component process in surface water and groundwater. The average recharge rate was estimated at approximately 20.8%.

• Journal of Korea Water Resources Association
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• v.32 no.1
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• pp.15-29
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• 1999

A new methodology to analyze and quantify regional meteorological drought based on annual precipitation data has been introduced in this paper In this study, based on posterior probability estimator and Bayesian classifier in Spatial Analysis Neural Network (SANN), point drought probabilities categorized as extreme, severe, mild, and non drought events has been defined, and a Bayesian Drought Severity Index (BPSI) has been introduced to classify the region of interest into four drought severities. In addition, to estimate the regional drought severity for the entire region, regional extreme, severe, mild, and non drought probabilities which are the areal averages of point drought probabilities over the region has been computed and applied. In this study, the proposed methodology has been applied to analyze the regional drought of South Korea during 1967-1996 years. The drought severity for the whole South Korea was defined spatially at each year and each year was classified in a drought severity criterion. The results may be useful for water manager to understand the South Korean drought with respect to the spatial and temporal variation.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.13-22
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• 2005

This paper classifies the topography of the Saemangeum Tidal flats based on Landsat TM satellite images by unsupervised ISODATA method, and analysis of the spatiotemporal changes of the classified shapes. The sedimental topography represents various properties according to the Saemangeum Tidal Embankment progress. We well proceed this study of the sedimental changes and distributions. By specifying the topographic characteristics of inner sea areas respectively, the investigation on the case study area according to the changes of the tidal will be useful in the establishment of land reclamation plan and the land use of the reclaimed area. In addition, the estuary image can be divided into tidal flats and sea surfaces using the band 4, also the detailed topography using the band 5, respectively among Landsat TM 7 bands. This paper contributes to the efficient image processing of the spatiotemporal sedimental changes.

• Journal of the Korean earth science society
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• v.33 no.3
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• pp.233-241
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• 2012

Based on the observation of the microwave radiometers at Cheongju, Hapcheon and Daegwallyeong in Korea, the precipitable water vapor and liquid water path have been analyzed for spatio-temporal characteristics. The observed datas have been validated by comparing precipitable water vapor between the microwave radiometer and the radiosonde near the sites. It resulted in the correlation coefficient of more than 0.8 in all three sites. For three regions, the precipitable water vapor shows similar seasonal variation and diurnal cycle, and that amount of precipitable water vapor increases from around 1000 LST and has a maximum value at 1900 LST. On the other hand, the liquid water path of microwave radiometer has regional differences for its seasonal variation, which seems to be caused by the geographical characteristics including the frequent fog and clouds in Daegwallyeong, a high mountain region (834 m from sea level), almost flat land in Chengju, and Sobaek Mountains in Hapcheon that blocks the westerly clouds.

• Journal of Korea Water Resources Association
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• v.33 no.S1
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• pp.327-332
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• 2000

최근 세계 각지에서는 엘리뇨 및 라니냐에 의한 기상변동에 의하여 막대한 인적, 경제적인 직간접적인 피해를 경험하여 왔다. 우리 나라의 기상에도 엘리뇨/라니냐의 영향이 시공간적으로 유의함이 최근 밝혀지고 있으며, 그에 따르는 엘리뇨/라니냐에 의한 영향의 정량적인 고려가 전국적인 수자원 장기 정책 및 관리에 필요함이 인식되어 왔다. 기상 이변 형상은 이미 실존의 현실이며, 이 중 엘리뇨/라니냐의 영향 또한 그러하다고 할 수 있다. 특히, 21세기는 물부족 및 물에 의한 재해의 가능성이 점차 증가될 것이라는 막연한 추측속에서 우리는 살고 있으나 실제적인 대책 및 연구에의 투자는 인색한 형편이다. 막상 닥쳤을 때만의, 당장의 아우성보다는 기초적인 바탕에서부터의 성실하고 결실을 맺을 수 있는 지속적인 연구가 수행되어야 한다. 왜냐하면, 미래는 현재의 연속이기 때문이다. 또한, 이의 연구는 기상, 수문, 수자원, 농업, 경제를 비롯한 여러 분야에서 다각적이고 연계적으로 이루어져야지 일방의 짧은 지식만으로 이루어 질 수는 없다. 본 연구에서는 엘리뇨/라니냐 영향 지수 산정 기법을 개발하고, 이를 이용하여 우리 나라에의 수자원에의 영향을 시공간적으로 정의하는데, 그 목적이 있다. 엘리뇨/라니냐 영향을 정의하기 위한 기법은 물리적인 기법과 통계적인 기법으로 크게 나뉠 수 있으나, 본 연구에서는 간략한 통게적인 기법을 이용하여 지수를 개발하였다. 이 지수는 엘리뇨/라니냐의 발생 강도뿐만 아니라 빈도를 동시에 고려할 수 있도록 하였다. 개발된 엘리뇨/라니냐의 영향 지수를 우선 우리나라 전역의 강수 기상 관측망 자료에 적용하였으며, 산정된 지수들을 공간적으로 Kriging 기법을 사용하여 공간 분포도(영향 지수도)를 작성하여 지역적인 영향 정도를 가시적으로 정의하였다.

• Journal of Korea Water Resources Association
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• v.37 no.1
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• pp.31-41
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• 2004

A soil moisture measuring method of hillslope for Korean watershed is developed to configure spatial-temporal distribution of soil moisture. Intensive surveying of topography had been performed to make a digital elevation model(DEM). Flow distribution algorithms were applied and a measurement system was established to maximize representative features of spatial variation. Soil moisture contribution mechanisms of rainfall-runoff process have been derived. Measurements were performed at the right side hillslope of Buprunsa located at the Sulmachun watershed. A Multiplex system has been operated and spatial-temporal soil moisture data have been acquired. Relatively high correlation relationship between flow distribution algorithm and measurement data can be found on the condition of high humidity.

• Journal of Korea Water Resources Association
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• v.38 no.5 s.154
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• pp.345-354
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• 2005

Time Domain Reflectometry (TDR) with multiplex system has been installed to configure the spatial and temporal characteristics of soil moisture at the Bumreunsa hillslope of Sulmachun Watershed. An intensive surveying was performed to build a refined digital elevation model (DEM) and flow determination algorithms with inverse surveying have been applied to establish an efficient soil moisture monitoring system. Soil moisture data were collected through intensive monitoring during 380 hrs in November of 2003. Soil moisture data shows corresponding variation characteristics of soil moisture on the upper, middle and lower parts of the hillslope which were classified from terrain analysis. Measured soil moisture data have been discussed on the context of physical process of hydrological modeling.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.1
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• pp.63-70
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• 2014

This study is to analyze impact of geography and timing on the real transactions prices of apartment complexes in Seoul using data provided by the Ministry of Land, Infrastructure and Transport. The average real transactions and location data of apartment complex was combined into the GIS data. First, the pattern of apartment real transaction price change by period and by area was analyzed by kriging, the one of the spatial interpolation technique. Second, to analyze the pattern of apartment market price change by administrative district(administrative 'Dong' unit), the average of market price per unit area was calculated and converted to Moran I value, which was used to analyze the clustering level of the real transaction price. Through the analysis, spatial-temporal distribution pattern can be found and the type of change can be forecasted. Therefore, this study can be referred as of the base data research for the housing or local policies. Also, the regional unbalanced apartment price can be presented by analyzing the vertical pattern of the change in the time series and the horizontal pattern of the change based on GIS.