• Atmosphere
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• v.21 no.2
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• pp.185-196
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• 2011

The performance assessment in radiosonde observation on the special observation program (ProbeX-2009) is performed and the characteristics of precipitation using Auto Weather System (AWS) and radiosonde data in 2009 at the Ulleungdo are investigated. The launching time, observation time, and maximum altitude of radiosonde are satisfied with the regulation from Korea Meteorological Administration (KMA) and World Meteorological Organization (WMO) but the duration of observational time of radiosonde is much shorter than that of the ProbeX-2007 because the altitude of launching site is higher than others in 2007. From the analysis of trajectories of radiosonde, most radiosondes at the Ulleungdo tend to move into the east because the westerly prevail at the middle latitude. However, when the Okhotsk high is expanded to the Korean peninsula and the north-westerly winds strengthen over the East Sea as the subtropical high is retreated, radiosonde tends to move into the south-west and south-east, respectively. Maximum distance appears at the end of observation level before May but the level of maximum distance is changed into 100 hPa after June because the prevailing wind direction is reversed from westerly to easterly at the stratosphere during summer time. The condition of precipitation was more correlated with the dynamic instability except Changma season. Precipitation in 2009 at the Ulleungdo occurred under the marine climate so that total precipitation amounts and precipitation intensity were increased and intensified during nighttime. The local environment favorable for the precipitation during nighttime was while the wind speed at the surface and the inflow from the shoreline were strengthened. Precipitation events also affected by synoptic condition but the localized effect induced by topography was more strengthened at the northern part of Ulleungdo.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.11-19
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• 2002

The seasonal variation of $^7Be$ and $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout collected at Daejeon during the period of 1998 - 1999 has been studied. The annual mean values of 7Be concentrations in airborne dust, precipitation and dry fallout were in the range of $3.80{\sim}4.29\;mBq\;m^{-3},\;1.25{\sim}1.67\;Bq\;l^{-1},\;19.7{\sim}22.3 MBq\;km^{-2}$, respectively. The annual mean values of $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout ranged $1.08{\sim}1.28{\mu}Bq\;m^{-3},\;0.44{\sim}2.66 mBq\;l^{-1}\;\;0.036{\sim}0.0455\;MBq\;km^{-2}$, respectively. While the concentrations of $^7Be$ and $^{137}Cs$ in airborne dust and dry fallout were relatively higher in the spring and autumn when the amount of dry fallout increased than in other season, their concentrations in precipitation were relatively lower in the summer when the rainfall increased. The total depositions of $^7Be$ and $^{137}Cs$ due to dry fallout and precipitation were in the range of $80.7{\sim}137MBq\;km^{-2}$ and $0.059{\sim}0.060MBq\;km^{-2}$, respectively. More than 80% of $^7Be$ deposition resulted from precipitation, whereas about 60% of $^{137}Cs$ deposition was due to dry fallout.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5B
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• pp.441-452
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• 2009

This paper describes the evaluation technique for climate change effect on daily precipitation frequency using daily precipitation generator that can use outputs of the climate model offered by IPCC DDC. Seoul station of KMA was selected as a study site. This study developed daily precipitation generation model based on two-state markov chain model which have transition probability, scale parameter, and shape parameter of Gamma-2 distribution. Each parameters were estimated from regression analysis between mentioned parameters and monthly total precipitation. Then the regression equations were applied for computing 4 parameters equal to monthly total precipitation downscaled by K-NN to generate daily precipitation considering climate change. A2 scenario of the BCM2 model was projected based on 20c3m(20th Century climate) scenario and difference of daily rainfall frequency was added to the observed rainfall frequency. Gumbel distribution function was used as a probability density function and parameters were estimated using probability weighted moments method for frequency analysis. As a result, there is a small decrease in 2020s and rainfall frequencies of 2050s, 2080s are little bit increased.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.469-472
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• 2003

A method that effectively precipitates capsular polysaccharide of Haemophilus influenzae type b (polyribosylribitol phosphate, PRP) conjugated to tetanus toxoid (TT), PRP TT in a liquid vaccine has been developed to measure free PRP present in TT-conjugate vaccine. The method involves adding anti-TT antibody and ammonium sulfate to precipitate PRP-TT conjugate and measuring free PRP in tile supernatant. This new method provides a complete precipitation of the total PRP-TT, and provides an accurate and reproducible measurements of free PRP. The accuracy of the assay was confirmed by spiking known amounts of unconjugated PRP to PRP-TT conjugate, and the new method was found to have no effect on free PRP while precipitating PRP-TT. The published acid precipitation method did not produce reproducible results due to incomplete precipitation of PRP-TT, especially when the vaccine is formulated in a salt-buffered solution.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.886-889
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• 2018

This article presented two-staged chemical precipitation for radioactive wastewater decontamination by using chemical agents. The total amount of radioactive wastewater was $35m^3$, and main radionuclides were Cs-137, Cs-134, and Co-60. Initial radioactivity concentration of the liquid waste was 2264, 17, and 9 Bq/L for Cs-137, Cs-134 and Co-60, respectively. Potassium ferrocyanide, nickel nitrate, and ferrum nitrate were selected as chemical agents at high pH levels 8-10 according to the laboratory jar tests. After the process, radioactivity was precipitated as sludge at the bottom of the tank and decontaminated clean liquid was evaluated depending on discharge limits. By this precipitation method decontamination factors were determined as 66.5, 8.6, and 9 for Cs-137, Cs-134, and Co-60, respectively. By using the potassium ferrocyanide, about 98% of the Cs-137 was removed at pH 9. At the bottom of the tank, radioactive sludge amount from both stages was totally $0.98m^3$. It was transferred by sludge pumps to cementation unit for solidification. By chemical processing, 97.2% of volume reduction was achieved. The potassium ferrocyanide in two-staged precipitation method could be used successfully in large-scale applications for removal of Cs-137, Cs-134, and Co-60.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.195-200
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• 2016

Water vapor leading various scale of atmospheric circulation and accounting for about 60% of the naturally occurring warming effect is important climate variables. Using the Total Precipitable Water (TPW) from Moderate Resolution Imaging Spectroradiometer (MODIS) operating on both Terra and Aqua, we study long-term Variation of TPW and define relationship among TPW and climatic parameters such as temperature and precipitation to quantitatively demonstrate the impact on climate change over East Asia focusing on the Korea peninsula. In this study, we used linear regression analysis to detect the correlation of TPW and temperature/precipitation and harmonic analysis to analyze changeable aspects of periodic characteristics. A result of analysis using linear regression analysis between TPW and climate elements, TPW shows a high determination coefficient ($R^2$) with temperature and precipitation (determination coefficient between TPW and temperature: 0.94, determination coefficient between TPW anomaly and temperature anomaly: 0.8, determination coefficient between TPW and precipitation: 0.73, determination coefficient between TPW anomaly and precipitation anomaly: 0.69). A result of harmonic analysis of TPW and precipitation of two-year to five-year cycle, amplitude contribution ratio of 3.5-year cycle are much higher and two phases are similar in 3.5-year cycle.

• Journal of the Korean association of regional geographers
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• v.1 no.1
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• pp.45-60
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• 1995

The purpose of this study is to classify the Korean precipitation regions on the basis of the characteristics of extratropical cyclonic precipitation. From now on, extratropical cyclone is called cyclone in short. By using factor analysis and Ward method in cluster analysis, precipitation regions on the basis of the characteristics of cyclonic precipitation are classified The principal data used in this study are daily precipitation records obtained from 60 weather stations of the Korea Meteorological Service during the ten years($1981{\sim}1990$), and weather charts published by the Japan Meteorological Agency. The results obtained in this study are summarized as follows: (1) In the factor analysis using 43 variables which have relation to the extratropical cyclonic precipitations, They are seven factors whose eigenvalues are above 1.0. This explains 86 percent of total amount. The first factor explains the characteristics of precipitation in the middle-west area and its contribution degree has the highest 10.9 percent. (2) According to the cluster analysis method of Ward, extratropical cyclonic precipitation regions are classified seven macro regions(such as Kyungki and North Youngseo, Youngdong and Ullungdo, Hoseo and South Youngseo, Honam and Northwest Chejudo, Southeast Chejudo, North Youngnam, and South Youngnam), 22 meso regions. (3) The characteristics of precipitation regions have relations to the path of cyclone, the direction of air inflow and the strike of mountain ranges. As the conclusion, the Central China Low brings much precipitation in the southern coast and southern area of Korea as moving to the northeastward. The North China Low moves eastward and brings much precipitation in the western area of the Taeback mountain ranges. The probability of extratropical cyclonic precipitation is the lowest in the inland of Yeongnam and the eastern coastal areas which belong to the rain shadow region. Namely, The seasonal and spatial characteristics of precipitation are closely associated with the path of cyclone and the direction of air inflow according to its passage, and the strike of mountain ranges.

• KIEAE Journal
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• v.6 no.3
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• pp.27-34
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• 2006

The recent emphasis on ecological urban development has led to the need to maintain a hydrologic cycle in urban areas. As such, this study proposes decentralized rainwater management, a concept of onsite rainwater management that involves the utilization, infiltration, detention, and retention of rainwater. The main objective of this research is to estimate the proportion of decentralized rainwater management that is needed. From the research that was conducted in this study, it was found that the total runoff quantity increases by 10-20% after district lands are developed, when the probable rate of precipitation every 10 years is within this range. Thus, the runoff rate can be reduced by 10~20% of the total runoff quantity through decentralization. On the other hand, in the scale of housing complex development, the total runoff quantity increases by as much as 10~40% due to the changes in the rate of the impervious surface area. If 10-40% of the total runoff quantity was processed through decentralized rainwater management, the rate of infiltration, detention, retention, and runoff in precipitation prior to development could be recovered.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.344-347
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• 1995

Factors affecting on the ascospore release of Mycosphaerella nawae, the causal organism of persimmon leaf casting disease, were investigated. The ascospore release of the pathogen occurred following the precipitation of rain. The ascospore release started from the beginning of raining, reached maximum at 2 hours after the precipitation of rain, and then decreased abruptly. When the inoculum source (a file of infected leaves) was submerged in water to imitate raining conditions, 92.5% of the total ascospores were released within 1 hour after submerging, 5.8% were after 2 hours, 1.4% were after 4 hours, 0.1% were after 8 hours, and none detected after 10 hours. The inoculum source overwintered in the field released ascospores much more and earlier than the inoculum source kept in the greenhouse. The first ascospore release was about 10 days earlier, and the amount of the total liberated spores was 3∼4 times higher in the field inoculum source than the greenhouse nioculum source. The early defoliated leaves (in early October) in the previous year produced ascospores twice more than the late defoliated leaves (in early November) produced.

• Journal of Environmental Science International
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• v.21 no.9
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• pp.1115-1129
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• 2012

The objective of this study was to analyze long-term annual and seasonal trends of water chemistry on landuse patterns and seasonal precipitation using 72 sampling sites within Namhan River watershed during 2001-2010. Water quality, based on multi-parameters of water temperature(WT), dissolved oxygen(DO), biochemical oxygen demand(BOD), chemical oxygen demand(COD), suspended solids(SS), total nitrogen(TN), total phosphorus(TP), and electric conductivity(EC) varied largely depending on monsoon rain and landuse patterns such as forest, cropland, and residence. Concentrations of BOD and COD as an indicator for organic matter pollution, increased during summer monsoon season at the cropland and residential streams. Values of TN and TP were higher in residential streams than in the forest and cropland streams. In the meantime, DO values had weak relations to the landuse patterns of forest and cropland cover. Water quality was worst in cropland and residential streams, and also most degradated in 4th order streams. Overall, our results suggest that efficient water quality management is required in the cropland and residential landuse streams.