• Journal of Korea Water Resources Association
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• v.51 no.7
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• pp.617-627
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• 2018

In this study, CMIP5 GCMs rainfall data (2011~2099) based on RCP scenarios were used to analyze the extreme drought evaluation for the future period. For prospective drought assessment, historical observations were used based on the Automated Surface Observing System (ASOS) data (1976~2010) of the Korea Meteorological Administration. Through the analysis of various indicators, such as average annual rainfall, rainy days, drought spell, and average drought severity was carried out for the drought evaluation of the five major river basins (Han river, Nakdong river, Geum river, Sumjin river, and Youngsan river) over the Korean peninsula. The GCMs that predicted the most severe future droughts are CMCC-CMS, IPSL-CM5A-LR and IPSL-CM5A-MR. Moderate future droughts were predicted from HadGEM2-CC, CMCC-CM and HadGEM2-ES. GCMs with relatively weak future drought forecasts were selected as CESM1-CAM5, MIROC-ESM-CHEM and CanESM2. The results of this study might be used as a fundamental data to choose a reasonable climate change scenario in future extreme drought evaluation.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.323-323
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• 2016

최근 강우강도 등의 기후변화로 인한 표토침식량이 증가하고 있고, 이에 따른 사회적 환경적 문제가 부각되고 있다. 특히 표토는 인류에게 식량생산의 기반이 되고, 정주공간을 제공할 뿐만 아니라 에너지 생산, 수자원 함양, 기후변화 대응, 생물 다양성 유지, 생태계의 건전성, 자원함양 및 순환, 오염물질 정화 등 소중한 생명자원이다. 이에 환경부에서는 2012월 12월 표토의 침식현황에 관한 고시를 제정하고, 표토 유실 대책 방안을 수립하기 위한 노력을 기울이고 있다. 이에 자원으로서의 표토를 보전하기 위한 단기적 관점의 대책 수립을 위한 웹GIS 기반 단일 강우에 의한 표토침식량을 예측하는 시스템을 개발하였다. 본 연구는 크게 표토침식 예측 모듈 개발과 정확성 평가를 위한 시험포 단위 모니터링 그리고 모듈을 적용한 웹GIS 시스템 개발, 시범적용을 위한 강원도 홍천군 자운리 DB 구축으로 구분된다. 표토침식예측 모듈의 정확성을 검증하기 위하여 가로 4m ${\times}$ 세로 22m, 경사도 3%, 9% 시험포 2개를 조성, 2015년 5월 11일부터 2015년 11월 23일까지 강우량, 유출량, 표토침식량을 조사하였으며, 웹 GIS 시스템은 Open Source Software인 Geoserver, PostGIS, OpenLayers를 활용하여 개발하였다. 마지막으로 개발된 웹GIS 표토침식예측시스템의 시범적용을 위하여 강원도 홍천군 자운리의 농경지 경계, 경사도, 경사장, 작물특성 등에 대한 GIS DB를 구축하였다. 시험포 모니터링 결과 강우발생일수는 총 64일로 관측되었고, 이중 유출은 총 30회가 발생되었다. 이 결과를 활용하여 표토침식 예측 모듈을 검증한 결과 3 % 시험포의 유출량 NSE : 0.88, $R^2$ : 0.91, 표토침식량 NSE : 0.87, $R^2$ : 0.90, 9 % 시험포의 유출량 NSE : 0.76, $R^2$ : 0.82, 표토 침식량 NSE : 0.82, $R^2$ : 0.88로 나타났다. 웹GIS 표토침식 예측 시스템은 Layer 정보, 맵, GIS tool, 경작기 정보, 날씨 정보 등으로 구성되어 있으며, 기상청 Open API와 연동하여 당일의 강수량 예보 데이터와 표토침식량 산정 모듈을 이용하여 예측 표토 침식량 데이터를 제공한다. 하루가 지나면 기상청에서 실측한 강수량 데이터를 이용하여 표토 침식량 산정모듈이 자동적으로 수행된 뒤 실측 강우량에 대한 표토침식량 정보가 제공된다 본 연구에서 개발된 웹GIS기반 표토침식 예측 시스템은 시범 대상 유역인 강원도 홍천군 자운리 유역을 대상으로 구축되었으며, 지속적으로 대상유역을 확대할 계획이다.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1317-1328
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• 2021

This study aims to provide a predictive model based on climate models for simulating continuous daily rainfall sequences by combining bias-correction and spatio-temporal downscaling approaches. For these purposes, this study proposes a combined modeling system by applying conditional Copula and Multisite Non-stationary Hidden Markov Model (MNHMM). The GloSea5 system releases the monthly rainfall prediction on the same day every week, however, there are noticeable differences in the updated prediction. It was confirmed that the monthly rainfall forecasts are effectively updated with the use of the Copula-based bias-correction approach. More specifically, the proposed bias-correction approach was validated for the period from 1991 to 2010 under the LOOCV scheme. Several rainfall statistics, such as rainfall amounts, consecutive rainfall frequency, consecutive zero rainfall frequency, and wet days, are well reproduced, which is expected to be highly effective as input data of the hydrological model. The difference in spatial coherence between the observed and simulated rainfall sequences over the entire weather stations was estimated in the range of -0.02~0.10, and the interdependence between rainfall stations in the watershed was effectively reproduced. Therefore, it is expected that the hydrological response of the watershed will be more realistically simulated when used as input data for the hydrological model.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.465-476
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• 2023

This study introduces the development of a precast concrete double-wall, applicable to basement construction in apartment buildings. Unlike traditional precast concrete double walls, the developed double-wall doesn't require specialized manufacturing equipment such as a lathe. The constructability of these advanced technologies was validated through a full-scale mock-up test using the precast concrete double wall. The test specimens were constructed to represent a structural wall with a thickness of 250mm. It was observed that the quality of the in-situ concrete, filled between two single panels of 110mm thickness each, was excellent. The construction efficiency of the developed double-wall system for basement construction in an apartment building was also examined. Expert interviews about installation times of precast concrete elements were conducted to evaluate the speed of the basement floor's installation. The results showed that installation of precast concrete elements, including the proposed double walls, could be completed within 20 to 29 days for a basement in an apartment building. This indicates a three-fold increase in construction efficiency compared to traditional methods relying on in-situ casting.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6B
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• pp.541-549
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• 2010

While the number of rainy days is decreasing, the mean annual precipitation is increasing due to abnormal climate changes caused by the global warming in Korea. Owing to the biased-concentration of rainfall during specific short terms, not only flood but also drought becomes more and more serious. From the literature, it is easily found that previous studies about flood have been intensively conducted. However, previous studies about drought have been performed rarely. This study conducted the comparison between two representative drought indexes calculated from soil moisture and precipitation. Study area was Haenam-gun, Jeollanam-do in Korea. Soil Moisture Index(SMI) was calculated from soil moisture data while the Standardized Precipitation Index(SPI) and the Palmer Drought Severity Index(PDSI) were calculated from meteorological data. All monthly data utilized in this study were observed at the KoFlux Tower. After the comparative analysis, three indexes showed similar tendency. Therefore, it is thought that the drought index using soil moisture measured at the KoFlux Tower is reasonable, which is because the soil moisture is immediately affected by all the meteorological factors.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.271-282
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• 2011

The purpose of this study is to clarify the discharge patterns of Yongnup, Daeam-san. Many hydrographs were analyzed by the types of rising and falling stages, and the slope of those stages with the semi-log graph paper was a key point to distinguish the discharge patterns during rainstorms. The correlation between rainfall intensity and slopes of the second or third rising stage was higher than that between slopes of the first rising stage and rainfall intensity. Also, the coefficient of correlation between discharge decrement and the lapsed time from the peak to inflection point of hydrograph, during high water stages, was better than that during low water stages. The annual average discharge rate of Yongnup was 0.54 and the average direct runoff ratio was 0.14. The total discharge amount from Yongnup was about 410,000 tons for a water year, the monthly maximum amount emerged in September and the minimum amount was occurred in March. In summer, 37.7% was a seasonal maximum runoff ratio; on the other hand, 9.4% was a seasonal minimum runoff ratio in winter.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.245-257
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• 2023

The representative crop in the Republic of Korea, rice, is cultivated over extensive areas every year, which resulting in reduced resistance to pests and diseases. One of the major rice diseases, rice blast disease, can lead to a significant decrease in yields when it occurs on a large scale, necessitating early detection and effective control of rice blast disease. Drone-based crop monitoring techniques are valuable for detecting abnormal growth, but frequent image capture for potential rice blast disease occurrences can consume significant labor and resources. The purpose of this study is to early detect rice blast disease using remote sensing data, such as drone and satellite images, along with weather data. Satellite images was helpful in identifying rice cultivation fields. Effective detection of paddy fields was achieved by utilizing vegetation and water indices. Subsequently, air temperature, relative humidity, and number of rainy days were used to calculate the risk of rice blast disease occurrence. An increase in the risk of disease occurrence implies a higher likelihood of disease development, and drone measurements perform at this time. Spectral reflectance changes in the red and near-infrared wavelength regions were observed at the locations where rice blast disease occurred. Clusters with low vegetation index values were observed at locations where rice blast disease occurred, and the time series data for drone images allowed for tracking the spread of the disease from these points. Finally, drone images captured before harvesting was used to generate spatial information on the incidence of rice blast disease in each field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.142-149
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• 1995

This study was conducted to investigate the relationships between yearly variation of climatic components and yearly variations of productivity in monoculture cotton. In addition, correlation coefficients among yield and yield components were estimated. The data of yield and yield components from the four varieties(Kinggus, Yongdang local. 113-4, 380) were collected from 1978 to 1992 in Mokpo area. The meteorological data gathered at the Mokpo Weather Station for the same period were used to find out the relationships between climatic components and productivity. Yearly variation of the amount of precipitation and number of stormy days in July are large with coefficients of the variations(C.V)84.89 and 97.05%, respectively, while yearly variation, of the average temperature, maximum temperature, minimum temperature from May to Sep. are relatively small. Seed cotton yield before frost in Sep. and Oct. very greatly with C.V. of 68.77, 78.52%, respectively. Number of boll bearing branches and lint percentage show more or less small in C.V. with 11.77 and 19.13%, respectively and flowering date and boll opening date show still less variation. Correlation coefficients between precipitation in May and number of boll bearing branches, duration of sunshine in July and number of bolls per plant, maximum temperature in July and total seed cotton before the frost in Sep., Oct., and Nov. evaporation in Aug. are positively sig-nificant at the 1% level. There are highly significantly positive correlated relationships among yield(total seed cotton) and yield components. Total seed cotton yield(Y) can be predicted by multiple regression equation with independent variables of climatic factors in July such as monthly averages of average temperature($X_1$), maximum temperature($X_2$) and minimum temperature($X_3$), monthly amount of precipitation ($X_4$), evaporation($X_5$), monthly average of relative humidity($X_6$), monthly hours with sunshine($X_7$) and number of rainy days($X_8$). The equation is estimatedas Y =-1080.8515 + 144.7133$X_1$+15.8722$X_2$ + 164.9367$X_3$ + 0.0802$X_4$ + 0.5932$X_5$ + 11.3373$X_6$ + 3.4683$X_7$- 9.0846$X_8$. Also, total seed cotton yield(Y) can be predicted by the same method with climatic components in Aug., Y =2835.2497 + 57.9134$X_1$ - 46.9055$X_2$ - 41.5886X$_3$ + 1.2559$X_5$ - 21.9687$X_6$ - 3.3763$X_7$- 4.1080$X_8$- 17.5586$X_9$. And the error between observed and theoretical yield were less with approached linear regression.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.233-243
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• 2011

This experiment was conducted to investigate the effect of future climate change on growing period and temperature in different rice maturity types as global warming progressed, where Odaebyeo, Hwaseongbyeo, Ilpumbyeo were used as a representative cultivar of early, medium, and medium-late rice maturity type, respectively, and A1B scenario was applied to weather data for future climate change at 57 sites in Korea. When cropping season was not adjusted to climate change, entire growing period and growing temperature were shorten and risen, respectively, as global warming progressed. On the other side, when cropping season was adjusted to climate change, growing period and temperature after heading date were not changed in contrast to growing period and growing temperature before heading which were more seriously shortened and risen as global warming progressed than in not adjusted cropping season. It is supposed that adjusting cropping season to climate change can alleviate rice yield reduction and quality deterioration to some degree by improving growing temperature condition during grain-filling period, but also still have a limit such as seriously shortened growing period indicating that there need to develope actively new rice cultivation methods and varieties for future climate change.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.100-107
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• 2021

Along with an increase in the frequency of high-concentration fine particulate matter in Korea, interest and research on ammonia (NH₃) are actively increasing. It is obvious that agriculture has contributed significantly to NH₃ emissions. However, studies on the long-term effect of fertilizer use on the ambient NH₃ concentration of agricultural land are insufficient. Therefore, in this study, NH₃ concentration in the atmosphere of agricultural land was monitored for 11 months using a passive sampler. The average ambient NH₃ concentration during the total study period was 2.02 ㎍ m^-3 and it was found that the effect of fertilizer application on the ambient NH₃ concentration was greatest in the month immediately following fertilizer application (highest ambient NH₃ concentration as 11.36㎍ m^-3). After that, it was expected that the NH₃ volatilization was promoted by increases in summer temperature and the concentration in the atmosphere was expected to increase. However, high NH₃ concentrations in the atmosphere were not observed due to strong rainfall that lasted for a long period. After that, the ambient NH₃ concentration gradually decreased through autumn and winter. In summary, when studying the contribution of fertilizer to the rate of domestic NH₃ emissions, it is necessary to look intensively for at least one month immediately after fertilizer application, and weather information such as precipitation and no-rain days should be considered in the field study.