SRTM(Shuttle Radar Topography Mission)의 정확성 평가

유승환,남원호,최진용,Yoo, Seung-Hwan,Nam, Won-Ho,Choi, Jin-Yong 한국관개배수위원회 2007 한국관개배수논문집 Vol.14 No.1

The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth. SRTM consisted of a specially modified radar system that flew onboard the Space shuttle SRTM consisted of a specially modified radar system that flew onboard the Space Shuttle Endeavour during an 11-day mission on February 2000. Since 2004, in a GLCF (Global Land Cover Facility, http;//glcf.umiacs.umd.edu/) web-site, products of SRTM including 1Km and 90m resolutions for outside US and a 30m resolution for the US have been provided. This study is to assess the accuracy of SRTM-DEM in comparing with NGIS-DEM generated from NGIS digital topographic map(1:25,000) in Guem river watershed. For the Geum river watershed, SREM-DEM elevation ranged from 0 to 1,605m and NGIS-DEM ranged from 6 to 1,610m, and the average elevation of SRTM-DEM was 226.7m and 218.9m for NGIS-DEM, respectively. NGIS-DEM was subtracted from SRTM in three zones -Zone I (0~100m), Zone II (100~400m), Zone III (over 400m)- to estimate difference between SRTM and NGIS-DEM. As the results, the differences of these DEM were 5.2m (11.6%) in Zone I, 8.8m (3.8%) in Zone II, 12.5m (2.1%) in Zone III. Although there were differences between SRTM-DEM and NGIS-DEM, SREM-DEM would be possible to be utilized as DEM data for the region where DEM is not prepared.

농업수자원 기후변화 영향평가를 위한 CMIP5 GCMs의 기후 전망자료 경향성 분석

유승환,김태곤,이상현,최진용,Yoo, Seung-Hwan,Kim, Taegon,Lee, Sang-Hyun,Choi, Jin-Yong 한국농공학회 2015 한국농공학회논문집 Vol.57 No.5

The majority of projections of future climate come from Global Circulation Models (GCMs), which vary in the way they were modeled the climate system, and so it produces different projections about conceptualizing of the weather system. To implement climate change impact assessment, it is necessary to analyze trends of various GCMs and select appropriate GCM. In this study, climate data in 25 GCMs 41 outputs provided by Coupled Model Intercomparison Project Phase 5 (CMIP5) was downscaled at eight stations. From preliminary analysis of variations in projected temperature, precipitation and evapotranspiration, five GCM outputs were identified as candidates for the climate change impact analysis as they cover wide ranges of the variations. Also, GCM outputs are compared with trends of HadGCM3-RA, which are established by the Korean Meteorological Administration. From the results, it can contribute to select appropriate GCMs and to obtain reasonable results for the assessment of climate change.

고해상도 기후시나리오를 이용한 논용수 수요량 및 단위용수량의 기후변화 영향 분석

유승환,최진용,이상현,오윤경,박나영,Yoo, Seung-Hwan,Choi, Jin-Yong,Lee, Sang-Hyun,Oh, Yun-Gyeong,Park, Na-Young 한국농공학회 2012 한국농공학회논문집 Vol.54 No.2

For stable and sustainable crop production, understanding the effects of climate changes on agricultural water resources is necessary to minimize the negative effects which might occur due to shifting weather conditions. Although various studies have been carried out in Korea concerning changes in evapotranspiration and irrigation water requirement, the findings are still difficult to utilize fordesigning the demand and unit duty of water, which are the design criteria of irrigation systems. In this study, the impact analysis of climate changes on the paddy water demand and unit duty of water was analyzed based on the high resolution climate change scenarios (specifically under the A1B scenario) provided by the Korea Meteorological Administration. The result of the study indicated that average changes in the paddy water demand in eight irrigation districts were estimated as -2.4 % (2025s), -0.2 % (2055s), and 3.2 % (2085s). The unit duty of water was estimated to increase on an average within 2 % during paddy transplanting season and within 5 % during growing season after transplanting. This result could be utilized for irrigation system design, agricultural water resource development, and rice paddy cultivation policy-making in South Korea.

한국의 밭작물 생산에서의 물발자국 산정

유승환,이상현,최진용,Yoo, Seung-Hwan,Lee, Sang-Hyun,Choi, Jin-Yong 한국농공학회 2014 한국농공학회논문집 Vol.56 No.3

Water footprint is defined as the total volume of direct and indirect water used to produce a good and service by consumer or producer, and measured at the point of production based on virtual water concept. The green and blue water footprint refers to the volume of the rainwater and the irrigation water consumed, respectively. Crop water footprint is expected to be used as the basic data for agricultural water resources policies at production, consumption and trade aspect. Thus, it is necessary to estimate suitable green and blue water footprint for South Korea. The objective of this paper is to quantify the green and blue water footprint and usage of upland crops during the period 2001-2010. To estimate the water footprint, 43 upland crop production quantity and harvested area data were collected for 10 years and FAO Penman-Monteith equation was adopted for calculating crop water requirement. As the results, the water footprint of cereals, vegetables, fruits and oil crops accounted for 1,994, 165, 605, and 4,226 $m^3/ton$, respectively. The usage of water footprint for crop production has been estimated at 3,499 (green water) and 216 (blue water) $Mm^3/yr$ on average showing a tendency to decrease. Fruits and vegetables have the largest share in the green water usage, consuming about 1,200 and 1,060 $Mm^3/yr$ which are about 65 % of gross usage. The results of this study are expected to be understood by the agricultural water footprint as well as by the total water footprint from both a production and consumption perspective in Korea.

농업가뭄대응을 위한 가뭄기상시나리오 모델 개발 및 적용

유승환,최진용,남원호,김태곤,고광돈,Yoo, Seung-Hwan,Choi, Jin-Yong,Nam, Won-Ho,Kim, Tae-Gon,Go, Gwang-Don 한국농공학회 2012 한국농공학회논문집 Vol.54 No.2

Different from other natural hazards including floods, drought advances slowly and spreads widely, so that the preparedness is quite important and effective to mitigate the impacts from drought. Evaluation and forecast the status of drought for the present and future utilizing the meteorological scenario for agricultural drought can be useful to set a plan for agricultural drought mitigation in agriculture water resource management. In this study, drought climate scenario model on the basis of historical drought records for preparing agricultural drought mitigation was developed. To consider dependency and correlation between various climate variables, this model was utilized the historical climate pattern using reference year setting of four drought levels. The reference year for drought level was determined based on the frequency analysis result of monthly effective rainfall. On the basis of this model, drought climate scenarios at Suwon and Icheon station were set up and these scenarios were applied on the water balance simulation of reservoir water storage for Madun reservoir as well as the soil moisture model for Gosam reservoir watershed. The results showed that drought climate scenarios in this study could be more useful for long-term forecast of longer than 2~3 months period rather than short-term forecast of below one month.

논벼에 대한 Penman-Monteith와 FAO Modified Penman 공식의 작물 계수 산정

유승환,최진용,장민원,Yoo Seung-Hwan,Choi Jin-Yong,Jang Min-Won 한국농공학회 2006 한국농공학회논문집 Vol.48 No.1

In 1998, Food and Agriculture Organization addressed that FAO Modified Penman method possibly over-estimates consumptive use of water comparing to the measured reference crop evapotranspiration (PET) and Penman-Monteith method can be better choice for accurate PET estimation. Nevertheless it is still difficult to find research efforts about paddy rice crop coefficient for Penman-Monteith method. This study aims to estimate paddy rice crop coefficients for Penman-Monteith and FAO modified Penman methods in the manner of comparing two equations. To estimate the crop coefficients, measured evapotranspiration data during 1982-1986 and 1995-1997 were used. The average Penman-Monteith crop coefficients ranged from 0.78 to 1.58 for translated paddy rice and from 0.87 to 1.74 for flood-direct seeded paddy rice. The average FAO Modified Penman crop coefficients ranged from 0.65 to 1.35 for translated paddy rice and from 0.70 to 1.58 for flood-direct seeded paddy rice.

둑높이기 농업용저수지의 환경용수 방류기준 설정

유승환,이상현,최진용,박태선,Yoo, Seung-Hwan,Lee, Sang-Hyun,Choi, Jin-Yong,Park, Tae-Seon 한국농공학회 2012 한국농공학회논문집 Vol.54 No.5

The main purposes of the agricultural reservoir enlargement (ARE) project are to secure water supply reliability (WSR) for agriculture and to release environmental water during dry seasons. In this study, an operational rule that will simultaneously satisfy both the above issues was developed. Initial amount of water storage at the beginning of non-irrigation season (1st October) was divided into 3 stages, and the target level of water storage at the beginning of irrigation seasons (1st April) was set up. Required operational curves and release amounts were estimated based on the stages and target water levels. To evaluate the applicability of this rule, the amount of water released for environmental purposes and WSRs were analyzed for three reservoirs (Unam, Jangchi and Topjeong). The ratio between annual amount of release and additional amount of water storage were 1.6, 1.85, and 4.1 for the Unam, Jangchi, Tapjeong reservoirs, respectively. Also, the WSRs of all reservoirs were found to become higher than when the design standard was applied. Therefore, it is considered that the proposed rule is more suitable for the enlarged agricultural reservoirs operation as it satisfies the WSRs while securing the environmental water release.

북한의 지역별 기상학적 가뭄의 평가와 유형분류

유승환,남원호,장민원,최진용,Yoo, Seung-Hwan,Nam, Won-Ho,Jang, Min-Won,Choi, Jin-Yong 한국농공학회 2008 한국농공학회논문집 Vol.50 No.4

North Korea is one of the most vulnerable countries of the world for drought but still it is difficult to find scientific researches for understanding of the drought characteristics. This study analyzed the temporal and spatial distribution of meterological drought severity and classified the drought development types in North Korea. All eleven drought indices were tested such as seasonal rainfall, PDS, SPI and so on, and then drew the drought risk map by each indicator using frequency analysis and GIS(Geographic Information Systems) for twenty one meteorological stations. In addition meteorological drought characteristics in North Korea was classified to six patterns on Si/Gun administrative units using cluster analysis on the drought indicators. The cluster III has the strongly drought-resistant area due to sufficient rainfall and the cluster V was considered as the most drought-vulnerable area, Pungsan and Sinpo, because of the severest drought condition for eight drought indicators. The results of this study are expected to be provided for the basic understanding of regionalized drought severity and characteristics confronting the risk of drought from climate variations in North Korea.

가상화 환경에서 사용자 선점형 Credit 스케줄러 구현

유승환 ( Seung-hwan Yoo ),김성천 ( Sung-chun Kim ) 한국정보처리학회 2009 한국정보처리학회 학술대회논문집 Vol.16 No.2

기존의 가상화 시스템에서 사용되던 스케줄러는 기존 서버 환경을 기반으로 구현되었다. 즉, 기존데스크톱 운영체계와는 달리 선점형 멀티테스킹 작업방식에 대한 고려가 부족하다. 때문에 본 논문에서는 데스크톱 환경에서 XEN 가상화 시스템을 사용할 경우 사용자 작업을 우선적으로 선점하는 Credit 스케줄러를 제시한다. Credit 스케줄러의 I/O 도메인 Boost 기능의 수정을 통해 데스크톱 사용자가 작업하는 가상 머신에 대한 성능을 향상시키는 Credit 스케줄러를 제안하였다. 또한 시뮬레이션을 통해 본 논문에서 제안한 스케줄러가 목적에 맞게 동작하는지 확인할 수 있었다.

농업가뭄대응을 위한 기상시나리오 모델 개발

유승환 ( Yoo Seung-hwan ),최진용 ( Choi Jin-yong ),장민원 ( Jang Min Won ),남원호 ( Nam Won-ho ),김태곤 ( Kim Tae-gon ) 한국농공학회 2008 한국농공학회 학술대회초록집 Vol.2008 No.-

Different from other natural hazards including floods, drought advances slowly and spreads widely, so that the preparedness is quite important and effective to mitigate the impacts from drought. Evaluation and forecast the status of drought for the present and future utilizing the meteorological scenario for agricultural drought can be useful to determine the agricultural drought mitigation for agriculture water resource management. This study calculated effective rainfall contributing to the runoff based on the historical rainfall data. The monthly effective rainfall for each return period computed using a frequency analysis, and determined the drought reference year for the determined meteorological scenario by each stage using the results of each return period.