• Title/Summary/Keyword: heavy precipitation

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Development of Investigation and Analysis Technique to Landslides and Its Application (산사태 조사.해석 기법의 개발 및 적용)

  • Kim, Kyeong-Su;Song, Young-Suk;Chae, Byung-Gon;Cho, Yong-Chan;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.18 no.1
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    • pp.69-81
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    • 2008
  • Landslide researches are divided to a method of interrelationship for various factors, method of predicting landslide possibility, and method of estimating landslide risk which are occurring landslides in the natural slope. Most of landslides occurred in natural slope are caused by a heavy rainfall in summer season. Weathered soil layer located in upper side of rock mass was occurred. As well as, they are announced to have an influence to geometry, geology, soil characteristics, and precipitation in the natural slope. In order to investigate and interpret the variety of landslides from field investigation to risk analysis, landslide analysis process due to geotechnical and geological opinions are systematically demanded. In this research, the study area is located in Macheon area, Gyeongsangnam-do and performed the landslide investigation. From the results of landslide investigation and analysis, optimized standard model based on natural landslide is proposed to high technical method of landslide investigation and interpretation.

A Study on The Non-Point Source Pollutant Load Routing Method (비점원 오염부하량 산정에 관한 연구)

  • Kim, Young-Seob;Lee, Gwan-Young
    • Journal of the Korean Society of Industry Convergence
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    • v.11 no.1
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    • pp.11-18
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    • 2008
  • After execute quantitative analysis that choose station and compose floodgate quality of water net and use floodgate data and quality of water data analysis target Sign of the cock as 1 dimension access for Non-point pollution source pollution and estimate of Gaeuncheon's at Kyongsangbukdo report to the Throne in this research, presented parameter conclusion notation model (AGNPS) in real condition of our agricultural area through comparison with spot value and result is as following in reply. With result observation and analysis result of the AGNPS model the comparison which it will pay from the hazard which it analyzes 2005, the rainfall thought which is used in the analysis to select 8 heavy rain thoughts 2005 July - is data until of September. Actual amount of rainfall 6.0~195.0 mm one time the antecedent precipitation showed API5 case 0.0~507.0mm and were observed peak flows (Qpeak) each from the P-1 $0.026m^3/sec{\sim}9.265m^3/sec$, from the P-2 $0.010m^3/sec-2.747m^3/sec$ and from the P-3c $0.064m^3/sec-13.482m^3/sec$ to show. Also amendment AMC condition it will be cool and it uses and the AGNPS model conference the result which it occurs, analysis and regression analysis of actual flow for as 0.992 very the possibility of getting the result which is good there was a decisive coefficient which is cool. But the gun is (T-P) with the total nitrogen (T-N) decisive coefficient each as 0.794 and 0.849 the presumption which is reliability generally will pay and with the fact that it will be the possibility of getting it is judged.

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Seasonal Variation of Planktonic Foraminifera Assemblage in response to Seasonal Shift of Inter-Tropical Convergence Zone in the Northeastern Equatorial Pacific (적도수렴대의 위치변화에 따른 북동태평양 적도해역의 부유성 유공충 군집의 계절변동)

  • Lee, Yuri;Asahi, Hirofumi;Woo, Han Jun;Kim, Hyung Jeek;Lee, Seong-Joo;Khim, Boo-Keun
    • Ocean and Polar Research
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    • v.36 no.4
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    • pp.437-445
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    • 2014
  • A time-series sediment trap was operated at a water depth of 4950 m from July 2003 to May 2004 at KOMO station ($10^{\circ}30^{\prime}N$, $131^{\circ}20^{\prime}W$) in the northeastern equatorial Pacific, with the aim of understanding the temporal variation of planktonic foraminifera assemblages in response to the seasonal shift of Inter-Tropical Convergence Zone (ITCZ). A total of 22130 planktonic foraminifera specimens belonging to 30 species and 11 genera were identified, which shows a distinct seasonal variation with high values (125~288 specimens $m^{-2}day^{-1}$) in the winter to spring (December-May) and low values (16~23 specimens $m^{-2}day^{-1}$) in the fall (September-November). In addition, seasonal ecological differences of foraminifera assemblages are distinctly recognizable: omnivorous foraminifera occurred predominantly during the summer season, whereas herbivorous ones were dominant during the winter season. Such seasonal variations correspond to the seasonal shift of the ITCZ. Enhanced occurrence of herbivorous species during the winter-spring season seems a result of surface water mixing generated by the southward shift of the ITCZ. The increase in omnivorous species during the summer season may be due to the northward movement of the ITCZ caused by weakened wind speed, resulting in the intensification of water column stratification and nutrient-poor environment. A significant reduction of planktonic foraminifera specimens during the fall is attributed to heavy precipitation and reduction in light intensity.

Study on the Improvement of Strength for 12% Chromium Steel Rotor (12% Cr 로터강의 강도 개선에 관한 연구)

  • Jang, Yun-Seok;O, Se-Uk
    • Journal of Ocean Engineering and Technology
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    • v.3 no.2
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    • pp.625-625
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    • 1989
  • To check technical improvement in the soundness and strength of 12% Cr steel rotor, a 25 tons of rotor with 65 tons of ingot was made in real size and was cut to pieces to take test samples, and the various mechanical tests such as impact, tensile, creep, and fatigue were carried out. The strengths are compared with those of 1% Cr-Mo-V rotor of same size. Microstructures of the samples are examined and reviewed. The results can be summarized as follows. 1) Fracture appearance transition temperatures are 80.deg. C at the center part and 60.deg. C near surface of 12% Cr rotor, and 8.deg. C near surface of 1% Cr-Mo-V rotor. 2) Comparative rapid softening occurs at higher temperatures above 600.deg. C for 12% Cr steel and 550.deg. C for 1% Cr-Mo-V steel in tension tests. 3) Fatigue crack propagation rate of 12% Cr steel is almost same as that of 1% Cr-Mo-V steel at the same corresponding surface part of the rotors. The crack growth rate of center part of 12% Cr rotor is faster than near surface part of the rotor, and the crack growth rate at the load condition of R=0.04 is slower than that of the load condition of R=0.5 for both 12% Cr steel and 1% Cr-Mo-V steel. 4) Crack growth rate of radial direction near surface of 12% Cr rotor is faster than that of transverse direction at the same part because of the difference in residual stresses. 5) Both creep and fatigue strengths of 12% Cr steel are superior to those of 1% Cr-Mo-V steel and the difference is thought the effect of climb and glide controlled creep by solid solution of alloying elements and dispersion of carbides.

Development of Pre-Processing and Bias Correction Modules for AMSU-A Satellite Data in the KIAPS Observation Processing System (KIAPS 관측자료 처리시스템에서의 AMSU-A 위성자료 초기 전처리와 편향보정 모듈 개발)

  • Lee, Sihye;Kim, Ju-Hye;Kang, Jeon-Ho;Chun, Hyoung-Wook
    • Atmosphere
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    • v.23 no.4
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    • pp.453-470
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    • 2013
  • As a part of the KIAPS Observation Processing System (KOPS), we have developed the modules of satellite radiance data pre-processing and quality control, which include observation operators to interpolate model state variables into radiances in observation space. AMSU-A (Advanced Microwave Sounding Unit-A) level-1d radiance data have been extracted using the BUFR (Binary Universal Form for the Representation of meteorological data) decoder and a first guess has been calculated with RTTOV (Radiative Transfer for TIROS Operational Vertical Sounder) version 10.2. For initial quality checks, the pixels contaminated by large amounts of cloud liquid water, heavy precipitation, and sea ice have been removed. Channels for assimilation, rejection, or monitoring have been respectively selected for different surface types since the errors from the skin temperature are caused by inaccurate surface emissivity. Correcting the bias caused by errors in the instruments and radiative transfer model is crucial in radiance data pre-processing. We have developed bias correction modules in two steps based on 30-day innovation statistics (observed radiance minus background; O-B). The scan bias correction has been calculated individually for each channel, satellite, and scan position. Then a multiple linear regression of the scan-bias-corrected innovations with several predictors has been employed to correct the airmass bias.

Dynamics of Phytoplankton Community after Formation of Turbid Water in Lake Imha (임하댐의 탁수 형성후 식물플랑크톤 군집 동태)

  • Lee, Kyung-Lak;Choi, Jae-Sin;Kim, Han-Soon;Park, Jung-Won
    • Korean Journal of Ecology and Environment
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    • v.38 no.3 s.113
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    • pp.429-434
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    • 2005
  • The dynamics of phytoplankton community after the formatiom of turbidity was assessed at Dam barrage of Lake Imha from May 2003 to July 2004. The maximum turbidity of 1221 NTU during September and October 2003 was well correlated with heavy precipitation caused by Typoon Maemi. A total of 102 phytoplankton taxa was identified and the most abundant phytoplankton group was Bacillariophyceae with 63 taxa, followed by Chlorophyceae with 23 taxa, Cyanophyceae with 9 taxa, 3 taxa each of Synurophyceae and Cryptophyceae and Euglenophyceae with 1 taxon. The total standing crops ranged between 270 indls. $mL^{-1}$ and 4,515 indls. $mL^{-1}$ during the investigation Periods. The three species, Cryptomonas ovata, Cyclotella sp. and Microcystis aeruginosa predominated in sequence after the decrease of turbidity.

Effect of Aging Treatment on the Microstructure and Low Temperature Tensile Properties in 5083 Aluminum Alloy Weldments (5083 Al합금 용접재의 조직 및 저온 인장성질메 미치는 시효처리의 영향)

  • Lee, T.C.;Lee, H.W.;Joo, D.W.;Lee, J.H.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.1
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    • pp.1-9
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    • 2000
  • The microstructural characteristics and low temperature tensile properties between $25^{\circ}C$ and $-196^{\circ}C$ for as-welded and age hardened specimen by using Al 5083-H321 for base metal, 5083-5356 and 5083-4043 weldments have been investigated. The hardness of 5083-5356 weldment decreases with aging treatment, whereas the weld region of 5083-4043 weldment shows remarkable increase in hardness after aging due to the precipitation of fine Si particle at the grain boundaries and interiors. Low temperature tensile properties of 5083 AI base metal, 5083-5356 and 5083-4043 weldments appear to be the increment of tensile strengths and elongations at the room temperature and $-196^{\circ}C$, while the decrement of tensile properties around $-50^{\circ}C$ is shown. Through the observation of fine serration to fracture in the stress-strain curve and tensile fractography, the increment of localized deformation leading to promote the neck initiation and the increment of the dimple size cause to decrease in tensile strengths and elongations around $-50^{\circ}C$. For the tensile specimen of the 5083 base metal, 5083-5356 and 5083-4043 weldments, the reason to increase in elongation after solution and aging treatment is the diminishment of fine pit, the resolution of Mg into the matrix and the spheridization of the eutectic Si.

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Monitoring of Climate Change of Northeast Asia and Background Atmosphere in Korea

  • Oh, Sung-Nam;Chung, Hyo-Sang;Choi, Jae-Cheon;Bang, So-Young;Hyun, Myung-Suk
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2003.11a
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    • pp.232-235
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    • 2003
  • In general, the parameters of climate change include aerosol chemical compounds, aerosol optical depth, greenhouse gases(carbon dioxide, CFCs, methane, nitrous oxide, tropospheric ozone), ozone distribution, precipitation acidity and chemical compounds, persistent organic pollutants and heavy metals, radioactivity, solar radiation including ultra-violet and standard meteorological parameters. Over the last ten years, the monitoring activities of Korea regarding to the climate change have been progressed within the WMO GAW and ACE-Asia IOP programs centered at the observation sites of Anmyeon and Jeju Gosan islands respectively. The Greenhouse gases were pointed out that standard air quality monitoring techniques are required to enhance data comparability and that data presentation formats need to be harmonized and easily understood. Especially, the impact of atmospheric aerosols on climate depends on their optical properties, which, in turn, are a function of aerosol size distribution and the spectral reflective indices. Aerosol optical depth and single scattering albedo in the visible are used as the two basic parameters in the atmospheric temperature variation studies. The former parameter is an indicator of the attenuation power of aerosols, while the latter represents the relative strength of scattering and absorption by aerosols. For aerosols with weak absorption, surface temperature decreases as the optical depth increases because of the domination of backscattering. For aerosols with strong absorption, however, warming could occur as the optical depth increases. The objective of the study is to characterize the means, variability, and trends of Greenhouse gases and aerosol properties on a regional basis using data from its baseline observatories in Korea peninsula. A further goal is to understand the factors that control radiative forcing of the greenhouse and aerosol.

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Characteristics of Runoff on Urban Watershed in Jeju island, Korea (제주도 도심하천 유역의 유출특성 해석)

  • Jung, Woo-Yul;Yang, Sung-Kee;Lee, Jun-Ho
    • Journal of Environmental Science International
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    • v.22 no.5
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    • pp.555-562
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    • 2013
  • Jeju Island, the heaviest raining area in Korea, is a volcanic Island located at the southernmost of Korea, but most streams are of the dry due to its hydrological/geological characteristics different from those of inland areas. Therefore, there are limitations in applying the results from the mainland to the studies on stream run-off characteristics analysis and water resource analysis of Jeju Island. In this study, the SWAT(soil & water assessment tool) model is used for the Hwabuk stream watershed located east of the downtown to calculate the long-term stream run-off rate, and WMS(watershed modeling system) and HEC-HMS(hydrologic modeling system) models are used to figure out the stream run-off characteristics due to short-term heavy rainfall. As the result of SWAT modelling for the long-term rainfall-runoff model for Hwabuk stream watershed in 2008, 5.66% of the average precipitation of the entire basin was run off, with 3.47% in 2009, 8.12% in 2010, and root mean square error(RMSE) and determination coefficient($R^2$) was 496.9 and 0.87, respectively, with model efficient(ME) of 0.72. From the results of WMS and HEC-HMS models which are short-term rainfall-runoff models, unless there was a preceding rainfall, the runoff occurred only for rainfall of 40mm or greater, and the run-off duration averaged 10~14 hours.

A Study on Quality Control Method for Minutely Rainfall Data (분 단위 강우자료의 품질 개선방안에 관한 연구)

  • Kim, Min-Seok;Moon, Young-Il
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.2
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    • pp.319-326
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    • 2015
  • Rainfall data is necessary component for water resources design and flood warning system. Most analysis are used long-term hourly data of surface synoptic stations from the Meteorological Administration, Ministry of land, Infrastructure and Transport and others. However, It will be used minutely data of more high density automatic weather stations than surface synoptic stations expecting to increase the frequency of heavy precipitation. But minutely data has a problem about quality of rainfall data by auto observation. This study analyzed about quality control method using automatic weather station's minutely rainfall data of meteorological administration. It was performed assessment of the quality control that was classified quality control of miss Data, outlier data and rainfall interpolation. This method will be utilized when hydrological analysis uses minute rainfall data.