• Journal of the Korean Geophysical Society
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• v.3 no.3
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• pp.201-212
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• 2000

Recent seismicity of the central region of South Korea is investigated by using the micro-earthquake data recorded at the seismic network of KNUE(Korea National University of Education) since December, 1997. About two earthquakes are observed each month, which indicates relatively low seismic activities of the region, without showing any temporal characteristics of seismicity. The b-value of the region obtained from the data we used is found to be about 1.15. The epicenters of the micro-earthquakes are mostly located in the Okchon Zone, especially around Munkyong area, Poeun-Sokri Mt.-Youngdong area, and Kunsan-Nonsan area.

• Korean Journal of Remote Sensing
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• v.29 no.3
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• pp.293-306
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• 2013

Hydrometeor type and Drop Size Distribution (DSD) in cloud are the fundamental properties that may help explain the rain formation processes and determine the parameters of radar meteorology. This study presents a preliminary analysis of hydrometeor types and DSD data of cloud measured with a PARSIVEL (PARticle SIze and VELocity) optical disdrometer at the site of Cloud Physics Observation System (CPOS, $37^{\circ}41^{\prime}N$, $128^{\circ}45^{\prime}E$, 843 m from sea level) in Daegwallyeong mountainside of Korea. The method has been validated by comparing the observed rainfall rates with the computed ones from the fitted distribution, using the physical data such as DSD, terminal velocity, and rain intensity which were measured by a Micro-Rain Radar (MRR) and a PARSIVEL optical disdrometer. The analysis period started in three cases: on rainy days with light rain (15.5 mm), moderate rain (76 mm), and heavy rain (121 mm), from March to November 2007, respectively.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.405-415
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• 2016

We analyzed the micro-meteorological characteristics during typical steam fog over the Gumi Reservoir of Nakdong river with the field observation data for recent 2 year(1 April 2013~31 March 2015) collected by the national institute of meteorological research, KMA. Steam fog occur when the cold drainage flows over the warm water surface. As the sensible and latent heat from water are provided to the air, the instability of lower atmosphere is increased. The resultant vertical mixing of warm, moist air near water surface and cold air aloft causes the formation of status cloud. The convection strengthened by radiative cooling of the upper part of the stratus causes the fog to propagate downward. Also, the temperature at the lowest atmosphere is increased rapidly and the inversion near surface disappear by these processes when the fog forms. The increase of wind speed is observed because the downward transportation of momentum is caused by vertical mixing.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.32-32
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• 2018

Flora investigations in Korea have been conducted by many researchers for diverse purposes. Accumulated flora investigation data has not been utilized efficiently because there is no accessible database for comparison. To overcome this shortcoming, we constructed web-based database of flora investigation, named as the Integrated Korean Flora Database (IKFD; http://www.floradb.net/intro.php). Until now, 284 flora references (263 papers, 14 reports and books, and 7 unpublished papers written in between 1962 and 2017) were digitalized into the database. From 134,711 records, 4,301 species belonging to 228 families and 1,079 genera were identified via mapping with two major Korean plant species lists. Polygon areas originated from references were used for distribution of plant species, identifying precise distribution area. It will be a better index to show plant ecological characteristics. Collected micro-climate data provided by Korea Meteorology Administration were also integrated in IFKD for understanding correlation between distribution of plants and micro-climate. Cold hardiness zone which has been utilized for classifying climate zones. 12 out of 26 zones identified based on micro-climate data in Korea were mapped with distribution of plants. More than half species were appeared in zone 6a, 6b, 7a, and 7b. Taken together with these results, IKFD will be a fundamental platform for understanding plants in Korea flora investigation as well as a new standard for classifying distribution of plants. Moreover, Biodiversity Observation Database (BODB; http://www.biodiversitydb.info/intro.php) which integrates plant distribution data was also integrated for further studies.

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.272-282
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• 2019

Although the knowledge of current seismicity is a critical information for making and implementing effective earthquake-related policy, the detailed seismicity information of the metropolitan areas with high-population density has been largely underestimated due to the high-level of cultural noise and small earthquake magnitude. This study presents 12 earthquakes including 2 earthquakes previously known and 10 additional earthquakes occurred from 2010 to 2017 in Busan, but they were unreported by the Korea Meteorological Administration. Matched filter technique is used to detect micro-earthquakes. Although the epicenters of micro-earthquakes though present a distinguished linearity, a correlation with faults in the area is unknown. A repeated micro-seismicity suggests that there are subsurface structures responsible for observed events. If large earthquakes occur along the fault in Busan, they may cause catastrophic natural disasters. Given the fact that the recent earthquakes did not accompany any surface signatures, it is highly recommended that the current micro-seismicity be investigated, and updated seismicity information be incorporated into establishing active fault maps in Korea.

• Journal of the Korean earth science society
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• v.36 no.6
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• pp.567-579
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• 2015

The accurate simulation of micro-scale weather phenomena such as fog using the mesoscale meteorological models is a very complex task. Especially, the uncertainty arisen from initial input data of the numerical models has a decisive effect on the accuracy of numerical models. The data assimilation is required to reduce the uncertainty of initial input data. In this study, the limitation of the mesoscale meteorological model was verified by WRF (Weather Research and Forecasting) model for a summer fog event around the Nakdong river in Korea. The sensitivity analyses of simulation accuracy from the numerical model were conducted using two different initial and boundary conditions: KLAPS (Korea Local Analysis and Prediction System) and LDAPS (Local Data Assimilation and Prediction System) data. In addition, the improvement of numerical model performance by FDDA (Four-Dimensional Data Assimilation) using the observational data from AWS (Automatic Weather System) was investigated. The result of sensitivity analysis showed that the accuracy of simulated air temperature, dew point temperature, and relative humidity with LDAPS data was higher than those of KLAPS, but the accuracy of the wind speed of LDAPS was lower than that of KLAPS. Significant difference was found in case of relative humidity where RMSE (Root Mean Square Error) for LDAPS and KLAPS was 15.7 and 35.6%, respectively. The RMSE for air temperature, wind speed, and relative humidity was improved by approximately $0.3^{\circ}C$, $0.2m\;s^{-1}$, and 2.2%, respectively after incorporating the FDDA.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.87-90
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• 2005

The FORMOSAT-3/COSMIC mission is a micro satellite mission to deploy a constellation of six micro satellites at low Earth orbits. The final mission orbit is of an altitude of 750-800 lan. It is a collaborative Taiwan-USA science experiment. Each satellite consists of three science payloads in which the GPS occultation experiment (GOX) payload will collect the GPS signals for the studies of meteorology, climate, space weather, and geodesy. The GOX onboard FORMOSAT -3 is designed as a GPS receiver with 4 antennas. The fore and aft limb antennas are installed on the front and back sides, respectively, and as well as the two precise orbit determination (POD) antennas. The precise orbit information is needed for both the occultation inversion and geodetic research. However, the instrument associated errors, such as the antenna phase center offset and even the different cable delay due to the geometric configuration of fore- and aft-positions of the POD antennas produce error on the orbit. Thus, the focus of this study is to investigate the impact of POD antenna parameter on the determination of precise satellite orbit. Furthermore, the effect of the accuracy of the determined satellite orbit on the retrieved atmospheric and ionospheric parameters is also examined. The CHAMP data, the FORMOSAT-3 satellite and orbit parameters, the Bernese 5.0 software, and the occultation data processing system are used in this work. The results show that 8 cm error on the POD antenna phase center can result in ~8 cm bias on the determined orbit and subsequently cause 0.2 K deviation on the retrieved atmospheric temperature at altitudes above 10 lan.

• Atmosphere
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• v.23 no.3
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• pp.265-273
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• 2013

To investigate properties of cloud and rainfall occurred at Boseong on 10 July 2012, Raindrop Size distributions (RSDs) and other parameters were analyzed using observation data collected by Micro Rain Radar (MRR) and PARticle SIze and VELocity (PARSIVEL) disdrometer located in the National center for intensive observation of severe weather at Boseong in the southwest of the Korean peninsula. In addition, time series of RSD parameters, relationship between reflectivity-rain rate, and vertical variation of rain rates-fall velocities below melting layer were examined. As a result, good agreements were found in the reflectivity-rain rate time series as well as their power relationships between MRR and PARSIVEL disdrometer. The rain rate was proportional to reflectivity, mean diameter, and inversely proportional to shape (${\mu}$), slope (${\Lambda}$), intercept ($N_0$) parameter of RSD. In comparison of the RSD, as rain rate was increased, the slope of RSD became less steep and the mean diameter became larger. Also, it was verified that reflectivities are classified in three categories (Category 1: Z (reflectivity) > 40 dBZ, Category 2: 30 dBZ < Z < 40 dBZ, Category 3: Z < 30 dBZ). As reflectivity was increased, rain rate was intensified and larger raindrops were existed, while reflectivity was decreased, shape (${\mu}$), slope (${\Lambda}$), intercept ($N_0$) parameter of RSD were increased. We expected that these results will lead to better understanding of microphysical process in convective rainfall system occurred during short-term period over Korean peninsula.

• Journal of Environmental Science International
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• v.12 no.6
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• pp.605-613
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• 2003

In order to make use of the protection effect against wind by the vegetation, it examined whether it should make what vegetation form and arrangement using the 2-dimensional non-hydrostatic model. When the foliage shielding factor increases, it becomes hard to take in protection effect against wind in a residential section. When it makes height of vegetation high, it becomes hard to take in protection effect against wind with height. In the comparison in the case where vegetation high is gradually made low toward wind-stream from a vegetation, and the case of making it low gradually, although former tends to receive the protection effect against wind by the vegetation, attenuation of wind velicity becomes large. In the comparison in the case where foliage shielding factor and distribution of density of leaf are gathered gradually toward wind-stream from a vegetation. It has been understood to evaluate to height the influence that the vegetation multi-layer model by which the heat revenue and expenditure in the direction of the vegetation height is considered is used, and to characterize the vegetation group by the parameter setting.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.6
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• pp.600-618
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• 2014

The metadata for urban meteorological observation is standardized through comparison with those established at the World Meteorological Organization and the Korea Meteorological Administration to understand the surrounding environment around the sites exactly and maintain the networks and sites efficiently. It categorizes into metadata for an observational network and observational sites. The latter is again divided into the metadata for station general information, local scale information, micro scale information, and visual information in order to explain urban environment in detail. The metadata also contains the static information such as urban structure, surface cover, metabolism, communication, building density, roof type, moisture/heat sources, and traffic as well as the update information on the environment change, maintenance, replacement, and/or calibration of sensors. The standardized metadata for urban meteorological observation is applied to the Weather Information Service Engine (WISE) integrated meteorological sensor network and sites installed at Incheon area. It will be very useful for site manager as well as researchers in fields of urban meteorology, radiation, surface energy balance, anthropogenic heat, turbulence, heat storage, and boundary layer processes.