• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1103-1106
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• 2004

The objective of this study is to induce the design drought rainfall by the methodology of L-moment including testing homogeneity, independence and outlier of the data of annual minimum monthly rainfall in 57 rainfall stations in Korea in terms of consecutive duration for 1, 2, 4, 6, 9 and 12 months. To select appropriate distribution of the data for annual minimum monthy rainfall by rainfall station, the distribution of generalized extreme value (GEV), generalized logistic (GLO) as well as that of generalized pareto (GPA) are applied and the appropriateness of the applied GEV, GLO, and GPA distribution is judged by L-moment ratio diagram and Kolmogorov-Smirnov (K-S) test. As for the annual minimum monthly rainfall measured by rainfall station and that stimulated by Monte Carlo techniques, the parameters of the appropriately selected GEV and GPA distributions are calculated by the methodology of L-moment and the design drought rainfall is induced. Through the comparative analysis of design drought rainfall induced by GEV and GPA distribution by rainfall station, the optimal design drought rainfall by rainfall station is provided.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.3
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• pp.4184-4194
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• 1976

Located in the southwestern part of Korea, the Yong San Gang river flows generally northeast to southwest, and because of the specific location, topography and climate, the basin area is subject to recurrent drought and flood damages. To eliminate the cause of such damages and ensure an increase in the farm income by means of effective irrigation supply and increased cropping intensity, efforts are being made to speed up implementation of an integrated agricultural development project which would include construction. of an estuary dam and irrigation facilities as well as land development and tidal reclarnation. In formulating a basin development project plan, it is necessary to study a series of long-term runoff data. The catchment area at the proposed estuary damsite is 3,471$\textrm{km}^2$ with the total length of the river channel up to this point reaching 138km. An analysis of runoff in this area was carried out. Rainfall was estimated by the Thiessen Network based on records available from 15 of the rainfall observation stations within the area. Out of the 15 stations, Kwang Ju and Mok Po stations were keeping long-term precipitation records exceeding some 60 years while the others were in possession of only 5-10 years records. The long-term records kept by those stations located in the center of the basin were used as base records and records kept by the remaining stations were supplemented using the coefficient of correlation between the records kept by the base stations and the remainder. The analyses indicate that the average annual rainfall measured at Kwang Ju during 1940-1972 (33 years) amounts to 1,262mm and the areal rainfall amounts to 1,236mm. For the purpose of runoff analysis, 7 observatories, were set up in the middle and lower reaches of the river and periodic measurements made by these stations permitted analysis of water levels and river flows. In particular, the long-term data available from Na Ju station significantly contributed to the analysis. The analysis, made by 4-stage Tank method, shows that the average annual runoff during 1940-1972 amounts to 2,189 million ㎥ at the runoff rate of 51%. As for the amount of monthly runoff, the maximum is 484.2 million ㎥ in July while the minimum is 48.3 million ㎥ in January.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.3
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• pp.252-261
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• 2018

This study was conducted to develop a method to generate daily maximum and minimum temperatures using monthly data. We analyzed 30-year daily weather data of the 23 meteorological stations in South Korea and elucidated the parameters for predicting annual trend (center value ($\hat{U}$), amplitude (C), deviation (T)) and daily fluctuation (A, B) of daily maximum and minimum temperature. We use national average values for C, T, A and B parameters, but the center value is derived from the annual average data on each stations. First, daily weather data were generated according to the occurrence of rainfall, then calibrated using monthly data, and finally, daily maximum and minimum daily temperatures were generated. With this method, we could generate daily weather data with more than 95% similar distribution to recorded data for all 23 stations. In addition, this method was able to generate Growing Degree Day(GDD) similar to the past data, and it could be applied to areas not subject to survey. This method is useful for generating daily data in case of having monthly data such as climate change scenarios.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1117-1123
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• 2014

Water is a necessary condition of plants, animals and human. The state of the water shortage, that drought is globally one of the most feared disasters. This study was calculated target standardized precipitation index with unit of region for judgment and preparation of drought in consideration of the regional characteristics. First of all, Standardized Precipitation Index (3) were calculated by monthly rainfall data from rainfall data more than 30 years of 88 stations. Parametric frequency and nonparametric frequency using boundary kernel density function were analysed using annual minimum data that were extracted from calculated SPI (3). Also, Target return period sets up 30 year and target SPI analysed unit of region using thiessen by result of nonparametric frequency. Analyzed result, Drought was entirely different from severity and frequency by region. This study results will contribute to a national water resources plan and disaster prevention measures with data foundation for judgment and preparation of drought in korea.

• Journal of Korean Society of Forest Science
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• v.84 no.3
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• pp.277-285
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• 1995

This study was conducted to understand the relationship between climatic factors and matsutake(Tricholoma matsutake) mushroom production. Data on local annual matsutake production collected from 29 locations from 1984 to 1993 were analyzed for stepwise and multiple regression with local climatic data, such as monthly maximum, minimum, and average air temperature, soil temperature, relative humidity, amount of rainfall, and number of rainy days. Correlation between monthly climatic factors and annual matsutake production was calculated in each location(Case 1), each year(Case 2), and each month(Case 3). In Case 1, number of rainy days and minimum temperature in Sep. showed positive correlation with matsutake production. In Case 2, maximum, minimum, and average temperature in June showed negative correlation with matsutake production. In Case 3, amount of precipitation in Sep. and Oct. number of rainy days in Sep., and minimum temperature in Sep. and Oct. showed positive correlation with matsutake production. In conclusion, amount of rainfall and number of rainy days in Sep. were the most important climatic factors and correlated positively with matsutake production. Below average air temperature in June was also beneficial for matsutake production.

• 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.

• Journal of Korea Water Resources Association
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• v.52 no.1
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• pp.71-82
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• 2019

The purpose of this study is to analyze the Mekong River streamflow alteration due to climate change. The future climate change scenarios were produced by bias corrections of the data from East Asia RCP 4.5 and 8.5 scenarios, given by HadGEM3-RA. Then, SWAT model was used for discharge simulation of the Kratie, the main point of the Mekong River (watershed area: $646,000km^2$, 88% of the annual average flow rate of the Mekong River). As a result of the climate change analysis, the annual precipitation of the Kratie upper-watershed increase in both scenarios compared to the baseline yearly average precipitation. The monthly precipitation increase is relatively large from June to November. In particular, precipitation fluctuated greatly in the RCP 8.5 rather than RCP 4.5. Monthly average maximum and minimum temperature are predicted to be increased in both scenarios. As well as precipitation, the temperature increase in RCP 8.5 scenarios was found to be more significant than RCP 4.5. In addition, as a result of the duration curve comparison, the streamflow variation will become larger in low and high flow rate and the drought will be further intensified in the future.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.1-8
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• 2013

This study was conducted to compare the local climate conditions and growth periods for the apple (Malus domestica 'Borkh') orchards at different altitudes (330, 500, and 670 m) in Jangsu-Gun, Korea. Observation data for the growth period show that the monthly mean air temperatures at the 'Hongro' apple orchard sites decrease with height at the rate of 1.0 to $3.0^{\circ}C$/100 m. The monthly minimum temperatures in April (blooming period for 'Hongro' apple) were 4.3, 2.9, and $0.4^{\circ}C$ at 330, 500, and 670 m, respectively. The monthly mean temperatures in September (i.e., the coloration and maturation period) were 20.6, 18.7, and $14.5^{\circ}C$, respectively. The annual precipitation range varied from 1,234 to 1,439 mm, which tended to increase with height. The heavy rainfall occurred in summer (June to August) and amounted to 827-933 mm. No significant differences in the duration of sunshine were observed amongst the orchards at three different altitudes. The earliest bud break was observed at the 330 m altitude (18 March 2009), which was 4 and 11 days earlier in comparison to those at 500 and 670 m, respectively. The time of full bloom at 330 m was 12 days ahead of that at 670 m. The optimal maturation of fruit (based on skin redness > 80%) was observed between 7 and 10 September at 330 m, 15 and 18 September at 500 m, and 21 and 23 September at 670 m.