• Atmosphere
• /
• v.24 no.2
• /
• pp.151-158
• /
• 2014

This study investigated a method for the discrimination of precipitation type using thickness of geopotential height at 1000~850 hPa and improved Matsuo's scheme over South Korea using 7 upper-level observations data during winter time from 2003 to 2008. With this research, it was suggested that thickness between snow and rain should range from 1281 to 1297 gpm at 1000~850 hPa. This threshold was suitable for determining precipitation type such as snow, sleet and rain and it was verified by investigation at 7 upper-level observation and 10 surface observation data for 3 years (2009~2011). In addition, precipitation types were separated properly by Matsuo's scheme and its improved one, which is a fuction of surface air temperature and relative humidity, when they lie in mixed sectors. Precipitation types in the mixed sector were subdivided into 5 sectors (rain, rain and snow, snow and rain, snow, and snow cover). We also present the decision table for monitoring and predicting precipitation types using model output of Korea Local Analysis and Prediction System (KLAPS) and observation data.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.1
• /
• pp.34-38
• /
• 1999

In order to develop a thin type ESP(Electrostatic Precipitator) for high efficient air-conditioner with low concentration of ozone generation, collecting electrode spacing should be narrower than that from Deutsch formula and minimizes discharge current in ionizer. In this paper, the effect of applied voltage on the precipitation efficiency and ozone concentration of scroll type ESP was studied. As a result, precipitation efficiency(one pass) was improved by about 30[%] from increment of collector voltage(3.5[㎸]). Precipitation efficiency was increased with increasing ionizer voltage. And after some point, the efficiency was saturated. At the point, voltage and ionizer current was 5.2[㎸] and 95$[\muA]$ per meter respectively. At these applied voltage conditions, ozone concentration was saturated about 0.01[ppm] after 3 hours in 23$[m^3]$ closed room test.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2015.11a
• /
• pp.206-207
• /
• 2015

Due to the nature of construction industry which is labor-intensive and outdoor mobile production industry, climatic changes work as a major factor affecting construction period and safety accident. In Korea, changes in the amount of precipitation are more severe than those in climate. In addition, climatic changes are also shown as a change in precipitation form. Thus, this study aims to provide baseline data for establishing safety regulations at construction sites by analyzing fatal accidents by precipitation type.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.509-521
• /
• 1994

This study is an effort to develop computer simulation model that produce precipitation patterns from stochastic model. A stochastic model is formulated for the process of daily precipitation with considering the sequences of wet and dry days and the precipitation amounts on wet days. This study consists of 2 papers and the process of precipitation occurrence is modelled by an alternate renewal process (ARP) in paper (I). In the ARP model for the precipitation occurrence, four discrete distributions, used to fit the wet and dry spells, were as follows; truncated binomial distribution (TBD), truncated Poisson distribution (TPD), truncated negative binomial distribution (TNBD), logarithmic series distribution (LSD). In companion paper (II) the process of occurrence is developed by Markov chain. The amounts of precipitation, given that precipitation has occurred, are described by a Gamma. Pearson Type-III, Extremal Type-III, and 3 parameter Weibull distribution. Daily precipitation series model consists of two models, A-Wand A-G model, by combining the process of precipitation occurrence and a continuous probability distribution on the precipitation of wet days. To evaluate the performance of the simulation model, output from the model was compared with historical data of 7 stations in the Nakdong and Seomjin river basin. The results of paper (1) show that it is possible to design a model for the synthetic generation of IX)int precipitation patterns.

• The Korean Journal of Quaternary Research
• /
• v.22 no.1
• /
• pp.13-22
• /
• 2008

The Indian summer monsoon behaved in an abnormal way in 2002 and as a result there was a large deficiency in precipitation (especially in July) over a large part of the Indian subcontinent. For the study of deficient monsoon of 2002, a recent version of the NCAR regional climate model (RegCM3) has been used to examine the important features of summer monsoon circulations and precipitation during 2002. The main characteristics of wind fields at lower level (850 hPa) and upper level (200 hPa) and precipitation simulated with the RegCM3 over the Indian subcontinent are studied using different cumulus parameterization schemes namely, mass flux schemes, a simplified Kuo-type scheme and Emanuel (EMU) scheme. The monsoon circulation features simulated by RegCM3 are compared with the NCEP/NCAR reanalysis and simulated precipitation is validated against observation from the Global Precipitation Climatology Centre (GPCC). Validation of the wind fields at lower and upper levels shows that the use of Arakawa and Schubert (AS) closure in Grell convection scheme, a Kuo type and Emanuel schemes produces results close to the NCEP/NCAR reanalysis. Similarly, precipitation simulated with RegCM3 over different homogeneous zones of India with the AS closure in Grell is more close to the corresponding observed monthly and seasonal values. RegcM3 simulation also captured the spatial distribution of deficient rainfall in 2002.

• Journal of the Korean Ceramic Society
• /
• v.34 no.12
• /
• pp.1247-1253
• /
• 1997

Sinter-active yttria powders were prepared by a solution precipitation with using a self-decomposing precipitation agent NH2CONH2(urea). The cold-pressed powders can be sintered to full density and the microstructure of grains less than 200 nm at a temperature as low as 120$0^{\circ}C$. The activity of the yttria powder has been controlled by varying nucleation conditions during precipitation and by minimizing formation of aggregates. The type of precursor is decisive in preparation of a sinter-active oxide powder, and urea is desirable as a precipitation agent for an active yttrium oxide powder.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.334-334
• /
• 2022

Improvement of old-fashioned rain gauge systems for automatic, timely, continuous, and accurate precipitation observation is highly essential for weather/climate prediction and natural hazards early warning, since the occurrence frequency and intensity of heavy and extreme precipitation events (especially floods) are recently getting more increase and severe worldwide due to climate change. Although rain gauge accuracy of 0.1 mm is recommended by the World Meteorological Organization (WMO), the traditional rain gauges in both weighting and tipping bucket types are often unable to meet that demand due to several existing technical limitations together with higher production and maintenance costs. Therefore, we aim to introduce a newly developed and cost-effective hybrid rain gauge system at 0.1 mm accuracy that combines advantages of weighting and tipping bucket types for continuous, automatic, and accurate precipitation observation, where the errors from long-term load cells and external environmental sources (e.g., winds) can be removed via an automatic drainage system and artificial intelligence-based data quality control procedure. Our rain gauge system consists of an instrument unit for measuring precipitation, a communication unit for transmitting and receiving measured precipitation signals, and a database unit for storing, processing, and analyzing precipitation data. This newly developed rain gauge was designed according to the weather instrument criteria, where precipitation amounts filled into the tipping bucket are measured considering the receiver's diameter, the maximum measurement of precipitation, drainage time, and the conductivity marking. Moreover, it is also designed to transmit the measured precipitation data stored in the PCB through RS232, RS485, and TCP/IP, together with connecting to the data logger to enable data collection and analysis based on user needs. Preliminary results from a comparison with an existing 1.0-mm tipping bucket rain gauge indicated that our developed rain gauge has an excellent performance in continuous precipitation observation with higher measurement accuracy, more correct precipitation days observed (120 days), and a lower error of roughly 27 mm occurred during the measurement period.

• Proceedings of the KIEE Conference
• /
• 2000.07e
• /
• pp.9-12
• /
• 2000

A new type electrolyzing cell with slits on parallel plate electrodes and wire-to-cylinder type electrode system has been proposed instead of the conventional parallel plate type. An investigation was carried out on the effect of the number and size of slits on ion precipitation and oxidant generation characteristics, evidenced by eliminated space charge limiting action and by elevated electric fields in active interelectrode spacing. And it is also studied on the effect of the diameter of wire electrode to ion precipitation and oxidant generation characteristics. With electrode with 48 slits, very oxidants generation water of 3.1 [ppmm] and 19.0 [ppmm] in positive electrode side were obtained with tap water and 0.1 [wt%] NaCl dissolved tap waterfed. In addition, with wire-to-cylinder type electrode system, it is found that oxidant contained water of 0.48 [ppmm] and 5.46 [ppmm] in positive electrode side were obtained with tap water and 0.1 [wt%] NaCl dissolved tap water fed for the case of discharge electrode diameter of 0.5 [$mm{\phi}$]. Consequently, very high ion precipitation and dense oxidant generation characteristics can be realized by having slits on the electrodes of conventional cell as these slits increase the electric fields and decrease the space charge limiting actions in interelectrode spacing.

• Korean Journal of Microbiology
• /
• v.12 no.4
• /
• pp.180-187
• /
• 1974

Of the Asp. spp. isolated by the Institute of Applied Microbiology, Kon-Kuk University, 7 strains were selected for the study of the immunological differencences among them using gel precipitation test. The strains were the following types : 1 type of flavus and 2 types of oryzae were isolated from Meju ; 1 type of flavus from Nuruk ; and each one type of flavus, parasiticus and oryzae from Kokja.Asp.flavus from ATCC, Asp. parasiticus nad Asp. niger NRRL strains were also used in the study as a standard. From this study, several points can be raised ; 1) There was no common antigenic property between Asp. niger and Asp. flavus, because of no formation of reaction line. Therefore, all strains could be easily distinguished. 2) There was common antigenic property, that is, the formation of reaction line between Asp. flavus and Asp. parasticus. Accordingly two strains could not be easily distinguished by the gel precipitation test. 3) Each type of oryzae, parasiticus and flavus of Asp. flavus group had common antigen one another as well as specific antigens only in the difference of the reaction lines, so they could be easily identified in the gel precipitation test. 4) Each isolated strain from Meju and Nuruk appeared to be identical. 5) It was shown that the gel precipitation test of serological methods was very useful for the classification of Asp. spp.

• Water for future
• /
• v.11 no.1
• /
• pp.59-68
• /
• 1978

According to the simplified Gringorten's method of extreme values from data samples, daily maximum precipitation and return period at several stations in the central part of Korea were estimated. And also, it was known that the distribution of daily maximum precipitation of Sogcho, Chuncheon, Kangreung, Seoul, Inchon, Suwon, Seosan, Cheongju and Daejeon area belong to an exponential type of distribution.