• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.237-242
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• 1998

Salt accumulation is frequently experienced in soils under protected cultivation. Since protected cultivation does not have rainfall and resulting infiltration, salt accumulation in the soils is inevitable. In this study, analyzed were chemical charecteristics of soils under protected cultivation to investigate the factors which may contribute the salt accumulation. Soil samples were collected from 99 protected cultivation facilities around An-sung Gun, Gyungki-Do and analyzed for electrical conductivity, pH, organic matter con-tents. The results showed that there was no significant trend of changes in electrical conductivity and pH along cultivation years. the only factor influencing salt accumulation was irrigation type. Soils in facilities using drip irrigation showed higher electrical conductivity than those using diversion-hose type irrigation.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.558-564
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• 1998

Flow rate, watertable and selected water quality of 2 small rural streams and 6 observation well located in Kangwon-do, Korea, were monitored land use of the watersheds was investigated to describe the trend of stream water quality for 2 years and groundwater quality for 1 year. Water qualities were analyzed with respect to BOD, SS, T-N, Nitrate, T-P and E-coli. Stream water quality and gorundwater quality directly concerned with the amount of rainfall and paddy fields. but water quality of watersheds is existed with other factor. Therefore, We have to continued monitoring and developing the best management practice.

• Journal of Environmental Science International
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• v.7 no.1
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• pp.1-7
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• 1998

This paper alms to estimate the change point of the precipitation in Pusan area using the several statistical approaches. The data concerning rainfall are extracted from the annual climatological report and monthly weather report issued by the Korean Meteorological Administration. The average annual precipitation at Pusan is 1471.6 mm, with a standard deviation of 406.0 mm, less than the normal(1486.0 mm). The trend of the annual precipitation is continuously decreasing after 1991 as a change point. And the statistical tests such as t-test and Wilcoxon rank sum test reveals that the average annual precipitation of after 1991 is less than that of before 1991 at 10% significance level. And the mean gnu성 precipitation In Kyongnam districts is also continuously decreasing after 1991 same as Pusan.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.289-292
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• 2002

In this study, a topography based hydrologic model (TOPMODEL) was tested on the Anseong-cheon watershed. Pit in watershed was removed by liner trend surface interpolator. The DTM Analysis program is used to derived a distribution of ln($a/tan{\beta}$) values from DEM (Digital Elevation Model) using the MDF (Multiple Direction Flow) algorithm of Quinn et al (1995). Current TOPMODEL program limits are number of time step, ln($a/tan{\beta}$) increment, delay histogram ordinate and size of subcatchment pixel maps. Therefore, TOPMODEL is not suitable for application of large watershed. Muskingum method and watershed division enhance grid pixel resolution for rainfall-runoff simulation accuracy.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.51-58
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• 2011

The objective of this study is to identify whether or not the ground water level is decreasing. We suggest a method of estimating the change in groundwater level using newly developed groundwater pumping station data. The Goseong area located in Gyeongnam province was selected considering three factors. First, this area demands relatively large amount of irrigation water because most of the land is used as a paddy field and the proportion of the paddy field within total arable land is increasing. Second, groundwater level data in nearby area are available since these are monitored by Water Management Information System (WAMIS). Third, many groundwater pumping stations have been developed in this area in order to overcome droughts thus detail information for pumping stations are available. Regression results indicate groundwater level has been decreased for over 20 years. This decreasing trend is due to the shortage of surface irrigation water which was caused by the decrease in rainfall.

• Journal of Industrial Technology
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• v.35
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• pp.23-30
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• 2015

In recent, the various methods to predict the hydrological impacts due to climate change have been developed and applied. Especially, the variability of the meteorological factors such as rainfall, temperature, and evaporation can impact on the ecosystem in a basin. The variability caused by climate change on the meteorological factors can be divided by a gradual and abrupt change. Therefore, in this study, the gradual change is detected by simple linear regression and Mann-Kendall trend test. Also, the abrupt change is detected by Bayesian change point analysis. Finally, the result using these methods can identify the meteorological threats in the Cheongmicheon basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.696-700
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• 2004

본 연구에서는 우리나라 주요 관측소의 연최대강수량과 연강수량을 내상으로 변동 및 경향을 분석하여 그 결과를 비교하였다. 강수 자료의 변화분석을 수행함에 있어 양질의 강수 자료를 수집하기 위하여 기상청 보유 관측소 중 30년 이상 강우 기록을 가지고 있는 관측소를 내상으로 연최대강수량과 연강수량 자료를 추출하였다. 강수 자료의 변화분석은 크게 2가지로 변동분석과 경향분석을 수행하였다. 변동분석은 강수 자료의 평균과 분산의 편차에 따른 변동점 가정을 이용하여 변동점 전${\cdot}$후 강수 자료의 평균과 분산 변화에 내하여 통계적 유의성을 검정하는 방법이다. 경향분석은 강수 자료의 증가 또는 감소의 경향을 매개변수적, 비매개변수적 방법으로 통계적 유의성을 검정하는 방법이다. 본 연구에서 수행한 변동 및 경향분석 결과 어떤 기후적 요인에 의하여 강수량이 변화했다는 길과는 통계적 유의성에서 확인되지 않았다. 그러나 강수량 도시(plot)를 통한 강수량의 변동 및 경향은 존재하는 것으로 나타났으며, 이는 빈도 해석에 의한 확률강수량 산정시 고려 대상이 된다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.1
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• pp.88-95
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• 1998

Salt accumulation is frequently experienced in soils under protected cultivation. Since protected cultivation does not bave rainfall and resulting infiltration, salt accumulation in the soils is inevitable. In this study, analyzed were chemical characteristics of soils under protected cultivation to investigate the factors which may contribute the salt accumulation. Soil samples were collected from 99 protected cultivation facilities around Ansung-Gun, Gyungki-Do and analyzed for electrical conductivity, PH, organic matter contents. The results showed that there was no significant trend of changes in electrical conductivity and pH along cultivation years. The only factor influencing salt acculmuation was irrigation type. Soils in facilities using drip irrigation showed higher electrical conductivity than these using diversion-hose type irrigation.

• 한국방재학회:학술대회논문집
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• 2010.02a
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• pp.53.1-53.1
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• 2010

수공구조물 설계 시 수문 설계빈도의 결정은 추정한계치방법과 주요 수공구조물의 설계빈도 표를 활용하여 결정되어지고 있다. 외국의 경우 수문 설계빈도가 결정되면 설계빈도와 자료의 수를 고려하여 지점빈도해석과 지역빈도해석을 수행한다. 하지만 국내의 주요 수공구조물의 설계수문량은 지점빈도해석만을 이용하여 산정하고 있는 실정이다. 국내의 수문자료의 관측기관이 짧다는 것을 고려하면, 지점빈도해석만을 이용하여 설계수문량을 결정하는 것은 효율적이고 안정적인 설계수문량을 산정하기에는 불충분하다 할 수 있다. 따라서 본 연구에서는 자료보유기간과 설계빈도를 고려하여 지점 및 지역빈도해석을 실시하고 지구의 온난화로 인한 강우 및 홍수량의 증가추세를 반영할 수 있는 비정상성 빈도해석법을 지점 및 지역빈도해석에 적용하였으며, 이를 수행하기 위한 실무프로그램을 개발, 제안하였다.

• Journal of Integrative Natural Science
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• v.6 no.1
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• pp.12-15
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• 2013

To combine the micro rain radar and microwave radiometer cloud liquid water, we estimate the cloud physical thickness from the difference between the MTSAT-1R cloud top height and cloud base height of visual observation of Daegwallyeong weather station, and the cloud liquid water path of micro rain radar is obtained by multiplying the liquid water content of micro rain radar and the estimated cloud physical thickness. The trend of microwave radiometer liquid water path agrees with that of the micro rain radar during small precipitation. We study these characteristics of micro rain radar and microwave radiometer for small precipitation to obtain the combined cloud water content of micro rain radar and microwave radiometer, constantly operated regardless to the rainfall.