• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.679-682
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• 2008

Probability precipitation is one of the most important factor for designing the hydrology structures. Probability precipitation is calculated based on the frequency analysis on each durations of annual maximum rainfall data. For frequency analysis we need a conversion factor between the rain data per random-time interval and fixed-time-interval. In this study, the minutely precipitation data on observatory of the Meteorological Administration are used for 37 stations. Therefore, we should conversion factors between the rain data per minute and fixed-time-interval.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.1
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• pp.15-24
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• 2006

Precipitation samples were collected at Anmyeon (1997 - 2004), Uljin, and Gosan (1998 ~ 2004), the background area of the Korean Peninsula. These samples were analyzed for the concentration of 9 major ionic components ($F^{-}$,$Cl^{-}$, $NO_{3}^{-}$, $SO_{4}^{2-}$, $Na^{+}$, $NH_{4}^{+}$, $K^{+}$, $Mg^{2+}$, $Ca^{2+}$) with including a pH and an electric conductivity. Data quality for these samples was verified by ion balance and conductivity balance which are based on GAW manual for precipitation chemistry and the number of valid data at Anmyeon, Uljin, and Gosan is 249, 173, and 188, respectively. During the study period, the precipitation-weighted average pH at Anmyeon, Uljin, and Gosan was found to be 4.81, 4.87 and 4.89, respectively and each annual average pH was showed below pH 5.6 for every site. From the frequency survey on the precipitation acidity, the occurrence rate of acid rain below pH 5.6 is greater than $80\%$ for every site. Particularly, the highest occurrence rate for strong acid rain below pH 4.5 was found at Anmyeon, $32.1\%$, compared with other sites ($10.4\%$ at Uljin, $15.4\%$ at Gosan). That's because acidifying species (nss-$SO_{4}^{2-}$, $NO_{3}^{-}$) are remarkably high concentration at Anmyeon.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.310-310
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• 2018

Generally, precipitation measurement were conducted with various authrities. Among these, the MOLIT conduct the hydrological survey for the water resource management such as flood and low-flow forecasting, drought countermeasure, streamflow management. There is totally 424 observatory were existed and each precipitation measurement were obtained and quality assuranced with 10-min interval. It could be arranged or estimated with nearby observatory and radar reflectivity when the total amount of precipitation are existed. The objective of the study is therefore to suggest the method to estimate missing data with rain radar reflectivity. To validate suggested method, 50 observartory were obtained, and the efficiency were analyzed with estimated and observed precipitation. As the result of the study, the suggested method has reliability, and can be used as a method for quality assurance.

• Atmosphere
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• v.25 no.3
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• pp.389-405
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• 2015

In this study, the occurrence circumstances of 3 cases (12 Jan 2006, 11 Jan 2008, 22 Feb 2009) when the freezing rain was observed at more than two observatories in a day with more than three times each observatory, were investigated. Following the advanced study about the same cases, we have tried to find more delicate differences in using the Korea Local Analysis and Prediction System (KLAPS; 5 km reanalysis data) that has the smallest grid scale at current situation. As results, three common characteristics are found: (1) Just before the occurrence of the freezing rain, the wind direction was consistently continuous and the wind speed was constant or gradually increased for at least 3 hr more. (2) Surface air temperature (Relative humidity) was respectively $3.08^{\circ}C$ (28.76%), $0.47^{\circ}C$ (50.07%) and $-3.60^{\circ}C$ (71.07%) 3 hr ago to break out the freezing rain. It means the freezing rain occurs in a wide range of atmospheric environments. However, the closer it got to the occurrence time of the freezing rain, the closer the surface air temperature was to $0^{\circ}C$, and the bigger the humidity of the surface air was. (3) The liquid precipitation formed in the upper atmosphere, met a cold advection bellower than 950 hPa level and suspected to be changed to the super-cooled condition.

• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.71-78
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• 2011

Yeong-Gwang N.P.P Private Environment Supervisory Organization analyzed over 3,000 samples including 10 marine and 24 land samples from the year 2,000 to 2009. According to the results of the analysis, artificial nuclides that resulted from the effect of Yeong-Gwang Nuclear Power Plant operations were not detected in most samples. However, from the rain and seawater samples, which were taken from inside the plants such as the intake, the discharge and the observatory, $^3H$ was detected although it was below the regulation level. The $^3H$ concentration detected in the rain taken from the observatory, by the yearly average criterion, was 30.5~40.0 $Bq{\cdot}L^{-1}$, which is around 20 times the $^3H$ concentration detected in the surroundings of the power plants, but it is 0.1% of the regulation level of 40,000 $Bq{\cdot}L^{-1}$. Also, $^3H$ concentration detected in the seawater taken from the intake and the discharge, by the yearly average criterion, was 2.75~17.8$Bq{\cdot}L^{-1}$, which means the concentration detected in the discharge is about 140~280% higher than that detected in the intake except the year 2006. Based on these results, it was determined that, although lower than the regulation level, the $^3H$ in gas and liquid form detected in the rain and seawater sampled from the observatory and the discharge was released into the environment from the power plants. Therefore, regular monitoring and analysis is required on the level of $^3H$ in the observatory and the discharge.

• The KIPS Transactions:PartA
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• v.17A no.4
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• pp.197-202
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• 2010

The recorder at observatory can save the measured data from water gauge and rain gauge at an interval of five minutes. And then, the RTU (Remote Terminal Unit) in observatory sends the measured data in the recorder to the TM (Telemetering) in FCO (Flood Control Office) at an interval of ten minutes using VHF or satellite communication. But the transmitted data is not the stored data at the recorder, it is just data that is measured at an interval of ten minutes. In the FCO, the transmitted data is analyzed in order to forecast the flood. And also one of the most important things is the maintenance of an observatory. In this paper, an effective management system for the flood forecast is proposed. It uses the CDMA and the Blutooth technology on PDA. The proposed system is very portable, and also easily able to send the data stored at the recorder in observatory to TM in FCO without RTU. And it allows us to view remotely the data of other observatories by downloading from the FCO. Hence the system can do efficiently the maintenance of observatory without wasting manpower and time.

• Acta Via Serica
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• v.8 no.2
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• pp.25-52
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• 2023

The astronomic observatory of Graw Village is located on Mount Dari Lolikan, facing the village. Graw is located in the foothills of Mount Ser-i-Rash, 25 km northeast of Erbil Governorate, Iraq. This study attempts to clarify the foundations of this observatory, its components, as well as the founder and the date of its establishment. The study made efforts to clarify the benefits of this calendar to local residents in their daily lives. The database for this study is based on direct observation of the observatory station. The observation included the recording date and position of sunset and the appearance of stars throughout the year. Observation and documentation for both sunset and stars were performed over several years due to weather conditions since observation was not possible on foggy and rainy days and nights. Each observation took five to ten minutes depending on the clarity of the sky. The observatory consists of a group of stone cones. Each cone was built by stones in a specific location after careful and long observation of the sunset. Efforts were made to observe the disappearance and reappearance of the stars based on the change in the position of the Earth in relation to the sun. Graw's calendar helped to recognize important times of the year, such as the winter and summer forties, which were very important, especially when snow covered the roads, transportation stopped, crops spoiled, and pets stayed in their barn. The most important features of the winter forties are the memories, experiences, and minds of the villagers' ancestors. The forties were associated with the arrival of cold and heavier rain throughout the year, which is consistent with modern science, as the angle at which the Earth rotates increases the number and activity of weather depressions that affect the study area during this period. This observatory has a close connection with the daily life of the villagers, especially in the past centuries. It helped the people of the area in their appointments to carry out their work in the field of agriculture. The observatory was also of great importance in the field of education in the past centuries, especially in traditional religious schools. It also appears from this research that the calendar has ancient roots, which extend back thousands of years, as evidenced by the Ezidis who follow an ancient religion whose roots extend back thousands of years and who fast during both the winter and summer forties annually, with the participation of people in various regions of the world. It is not known who made this astronomic observatory but most of the oral information that has been passed down to us by word of mouth agrees on both Mullah Abdullah Al-Kurdi and Mullah Omar. Likely, this astronomic observatory was built around the late 17^th and early 18^th centuries.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.113-125
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• 2007

To know the differences in ionic compositions in rain and snow as well as snow influence on the chemical characteristics of winter precipitation, precipitation samples were collected by the wet-only automatic precipitation sample, in winter(November-February) in the Iksan located in the northwest of Chonbuk from 1995 to 2000. The samples were analyzed for concentrations of water-soluble ion species, in addition to pH and electrical conductivity. The mean pH of winter precipitation was 4.72. According to the type of winter precipitation, the mean pH of rain was 4.67 and lower than 5.05 in snow. The frequencies of pH below 5.0 in rain were about 73%, while those in snow were about 30%. Snow contained 3 times higher concentrations of sea salt ion components originated from seawater than did rain in winter, mainly $Cl^-,\;Na^+$, and $Mg^{2+}$. Neglecting sea salt ion components, $nss-SO_4^{2-}$ and $NO_3^-$ were important anions and $NH_4^+$ and $nss-Ca^{2+}$ were important cations in both of rain and snow. Concentrations of $nss-SO_4^{2-}$ was 1.3 times higher in rain than in snow, while those of $nss-Ca^{2+}$ and $NO_3^-$ were 1.5 and 1.3 times higher in snow, respectively. The mean equivalent concentration ratio of $nss-SO_4^{2-}/NO_3^-$ in winter precipitation were 2.4, which implied that the relative contribution of sulfuric and nitric acids to the precipitation acidity was 71% and 29%, respectively. The ratio in rain was 2.7 and higher than 1.5 in snow. These results suggest that the difference of $NO_3^-$ in rain and snow could be due to the more effective scavenging of $HNO_3$ vapor than particulate sulfate or nitrate by snow. The lower ratio in snow than rain is consistent with the measurement results of foreign other investigators and with scavenging theory of atmospheric aerosols. Although substantial $nss-SO_4^{2-}$ and $NO_3^-$ were observed in both of rain and snow, the corresponding presence of $NH_4^+,\;nss-Ca^{2+},\;nss-K^+$ suggested the significant neutralization of rain and snow. Differences in chemical composition of non-sea salt ions and neutralizing rapacity of $NH_4^+,\;nss-Ca^{2+}$, and $nss-K^+$ between rain and snow could explain the acidity difference of rain and snow. Snow affected that winter precipitation could be less acidic due to its higher neutralizing rapacity.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.54-55
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• 2015

Increase of impervious areas due to expansion of housing area, commercial and business building of urban is resulting in property change of stormwater runoff. Also, rapid urbanization and heavy rain due to climate change lead to urban flood and debris flow damage. In 2010 and 2011, Seoul had experienced shocking flooding damages by heavy rain. All these have led to increased interest in applying LID and decentralized rainwater management as a means of urban hydrologic cycle restoration and Natural Disaster Prevention such as flooding and so on. Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Low Impact Development (LID) methods is to mimic the predevelopment site hydrology by using site design techniques that store, infiltrate, evaporate, detain runoff, and reduction flooding. Use of these techniques helps to reduce off-site runoff and ensure adequate groundwater recharge. The contents of this paper include a hydrologic analysis on a site and an evaluation of flooding reduction effect of LID practice facilities planned on the site. The region of this Case study is LID Rainwater Management Demonstration District in A-new town and P-new town, Korea. LID Practice facilities were designed on the area of rainwater management demonstration district in new town. We performed analysis of reduction effect about flood discharge. SWMM5 has been developed as a model to analyze the hydrologic impacts of LID facilities. For this study, we used weather data for around 38 years from January 1973 to August 2014 collected from the new town City Observatory near the district. Using the weather data, we performed continuous simulation of urban runoff in order to analyze impacts on the Stream from the development of the district and the installation of LID facilities. This is a new approach to stormwater management system which is different from existing end-of-pipe type management system. We suggest that LID should be discussed as a efficient method of urban disasters and climate change control in future land use, sewer and stormwater management planning.

• Atmosphere
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• v.20 no.1
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• pp.1-12
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• 2010

Temporal distributions and characteristics of PWV (Precipitable Water Vapor) and LWP (Liquid Water Path) are investigated by using the microwave radiometric profiler at Haenam NCIO from 1 August 2007 to 31 July 2008. Temporal variations of PWV are closely connected with the thermal response of water vapor in atmosphere. The variations of LWP are characterized by the rainfall variation being basically attributable to the heavy rain-bearing clouds. The frequency distributions of PWV and LWP according to the four sky conditions ('clear', 'lightly cloudy', 'cloudy', and 'deeply cloudy') by total cloud amount at Wando Observatory corresponds with a change of slope in cumulative distribution function for PWV and LWP. There results implies that the classification of sky condition can be applied by using the distribution of PWV and LWP from microwave radiometric profiler.