• Atmosphere
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• v.16 no.4
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• pp.279-301
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• 2006

This study analyzed the characteristics of the wind waves near the Korean marginal seas in the 2002 - 2005 year using the third generation wave model, WAVEWATCH - III model. In order to investigate the model performance, model results were compared with the marine meteorological observation results. The 4 years average correlation coefficient between model and observation shows very high value of about 0.77. The model of this study represents very well the characteristics of wind waves near the Korean marginal seas. Simulated monthly sea surface winds and wind waves show the evident spatial variations and this model also simulates very well seasonal characteristics of wind waves in this region.

• Atmosphere
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• v.20 no.2
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• pp.195-210
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• 2010

This study uses mesoscale model WRF to investigate characteristics of wind fields in South Korea, a region with a complex terrain. Hourly wind fields were simulated for one year representing mean characteristics of an 11-year period from year 1998 to year 2008. The simulations were performed on a nested grid from 27 km down to 1 km horizontal resolution. Seasonal variation of wind speed indicates that wind is strongest during the spring and winter seasons. Spatial distribution of mean wind speed shows wind energy potential at its peak in mountainous region of Gangwon-do, the east coast, and Jeju Island. Wind speed peaks at night in mountainous and eastern coastal regions, and in the afternoon inland and in the southwestern coastal region. The simulated wind map was verified with four upper-air sounding observations. Wind speed was shown to have a more pronounced overestimation tendency relative to observation in the winter rather than summer. The results of this wind mapping study help identify locations with the highest wind energy potential in South Korea.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.287-292
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• 1999

This study was performed to investigate the characteristics of nocturnal maxiumu ozone occurrence and the meteorological relevance using to hourly ozone data and meteorological data for 1995~1996 in Pusan coastal area. Kwangbokdong showed the highest occurrence of nocturnal maximum ozone as 36.9%, and Deokcheondong showed the lowest occurrence(9.2%) for research period in Pusan. The occurrence rates of nocturnal maximum ozone concentration were decreased toward land area. The low maximum temperature, high minimum temperature, low diurnal range, high relative humidity, high wind speed, high could amount, low sunshine and low radiation were closely related to the main meteorological characteristics occuring the nocturnal maximum concnetration of ozone. It was shown that normal daily variation of ozone concentration by strong photochemical reaction at the before day of nocturnal maximum ozone. The concnetration of nocturnal maximum ozone were occured by entrainment of ozone from the upper layer of developed mixing layer. There are no ozone sources near the ground at night, so that the nighttime ozone should be entrained from the upper layer by forced convection.

• Atmosphere
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• v.19 no.2
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• pp.127-143
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• 2009

This study investigates characteristics of wintertime simulation conducted by METRI AGCM utilizing new radiation parameterization scheme. New radiation scheme is based on the method of Chou et al., and is utilized in the METRI AGCM recently. In order to analyze characteristics of seasonal simulation in boreal winter, hindcast dataset from 1979 to 2005 is produced in two experiments - control run (CTRL) and new model's run (RADI). Also, changes in performance skill and predictability due to implementation of new radiation scheme are examined. In the wintertime simulation, the RADI experiment tends to reduce warm bias in the upper troposphere probably due to intensification of longwave radiative cooling over the whole troposphere. The radiative cooling effect is related to weakening of longitudinal temperature gradient, leading to weaker tropospheric jet in the upper troposphere. In addition, changes in vertical thermodynamic structure have an influence on reduction of tropical precipitation. Moreover, the RADI case is less sensitive to variation of tropical sea surface temperature than the CTRL case, even though the RADI case simulates the mean climate pattern well. It implies that the RADI run does not have significant improvement in seasonal prediction point of view.

• Atmosphere
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• v.16 no.3
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• pp.225-234
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• 2006

Convective systems propagate eastward with a persistent pattern in the longitude-time space. The characteristic structure and fluctuation of convective system is helpful in determining its predictability. In this study, convective index (CI) was defined as a difference between GOES-9 window and water vapor channel brightness temperatures following Mosher (2001). Then the temporal-spatial scales and variational characteristics of the summer convective systems in the East Asia were analyzed. It is found that the average moving speed of the convective system is about 14 m/s which is much faster than the low pressure system in the summer. Their average duration is about 12 hours and the average length of the cloud streak is about 750km. These characteristics are consistent with results from other studies. Although the convective systems are forced by the synoptic system and are mostly developed in the eastern edge of the Tibetan Plateau, they have a persistent pattern, i.e., appearance of the maximum intensity of convective systems, as they approach the Korean Peninsula. The consistency of the convective systems, i.e., the eastward propagation, suggests that there exists an intrinsic predictability.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.242-249
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• 2004

This study was conducted to develop a forest fire occurrence model using meteorological characteristics for the practical purpose of forecasting forest fire danger. Forest fire in South Korea is highly influenced by humidity, wind speed, and temperature. To effectively forecast forest fire occurrence, we need to develop a forest fire danger rating model using weather factors associated with forest fire. Forest fore occurrence patterns were investigated statistically to develop a forest fire danger rating index using time series weather data sets collected from 8 meteorological observation centers. The data sets were for 5 years from 1997 through 2001. Development of the forest fire occurrence probability model used a logistic regression function with forest fire occurrence data and meteorological variables. An eight-province probability model by was developed. The meteorological variables that emerged as affective to forest fire occurrence are effective humidity, wind speed, and temperature. A forest fire occurrence danger rating index of through 10 was developed as a function of daily weather index (DWI).

• Atmosphere
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• v.20 no.2
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• pp.161-172
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• 2010

In an effort to investigate the characteristics of synoptic meteorological conditions in association with long-range transport of haze phenomena occurred over Korea, we statistically classified characteristics of haze events into two types of haze: stagnant case and long-range transport case, based on the synoptic meteorological parameters, and analyze comparatively the characteristics of synoptic meteorological conditions for each case. The results showed that the occurrence frequency of stagnant case accounts for 64.5%, showing superiority of stagnant haze cases over the long-range transport case which occupies only 35.5% among total 67 cases for the period from 2000 to 2007. This result indicates that haze phenomena occurred over Korea has influenced by not only the emission in Korea by itself but long range transport effects originating from China inland. The synoptic condition on 850hPa level showed that, when stagnant case occurred, Korean peninsula was located under the effects of negative vorticity with the significantly weak wind speed and stable atmospheric condition. In contrast, long-range transport case shows positive vorticity and relatively strong wind speed over 850hPa level, especially with the location of high pressure system over the area of southwestern China. This location of high pressure system implies to induce the westerlies or northwesteries consistently due to its pressure gradient by itself. Also other comparative studies haze days (vs.) Asian dust days are carried out, and we found out that the patterns of long-range transport of haze phenomena in Korea shows similar to Asian dust case but the static stability condition indicates more stabilized atmospheric condition than dust phenomena.

• Atmosphere
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• v.18 no.2
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• pp.137-146
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• 2008

This study examines one thermal index, perceived temperature (PT), over the Korean Peninsula during 2007 summer. Heat/cold stress has been described using air temperature and humidity for warm seasons and air temperature and wind velocity in the cold conditions, while PT is based on a heat budget model of the human body that considers air temperature, humidity, wind velocity and radiation effect regardless of climates, regions and seasons. PT is higher about $4-5^{\circ}C$ than air temperature in the summer. Humidity increases PT, while wind tends to reduces PT possibly by evaporation of water vapor. The geographical distribution of summer PT indicates that the lowest PT happened in the east central region, with the appearance of the highest PT in the inland of southern region in Korea. Although the latitudinal trend shows that PT decreases northward, inland PT is higher than that of coastal region. Compared to the heat index or the discomfort index that considers air temperature and humidity, PT represents distinctive regional characteristics of thermal comfort. The distribution of PT shows that it may be a useful thermal index for the assessment of thermal comfort or stress region in the Korean Peninsula.

• Atmosphere
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• v.26 no.1
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• pp.47-58
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• 2016

On 10 July 2014, tornado outbreak occurred over Goyang province in Korea. This was the first supercell tornado ever reported or documented in Korea. The characteristics of the supercell tornado were investigated using an X-band polarimetric radar, surface meteorological observation, wind profiler, and operational numerical weather prediction (Regional Data Assimilation and Prediction System, RDAPS). The supercell tornado developed along a preexisting dryline that was contributed to surface wind shear. The radar analyses examined here show that the supercell tornado indicated a hook echo with mesocyclone. The decending reflectivity core as well was detected before tornadogenesis and prior to intensification of supercell. The supercell tornado exhibited characteristics similar to typical supercell tornado over the Great Plains of the United States, such as hook echo, bounded weak echo region, and slower movement speed relative to the mean wind. Compared to the typical supercell tornado over U.S., this tornado showed horizontal scale of the mesocyclone was relatively smaller and left-mover.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.773-787
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• 2003

There are variations in the temperature Held due to urban heat island and anthropogenic heating so that regional scale meteorological field is changed. Therefore we simulate and predict the regional climate change according to surface characteristics through regional meteorological model. This study investigates the regional meteorological field by urbanization that influences in local circulation system using CSU-RAMS and simulates dry deposition velocity (V$_{d}$) using PNU/DEM which includes surface characteristics (such as albedo, surface hydrology and rough-ness length etc.) with calculated meteorological field. During the summer, horizontal distributions of V$_{d}$ were simulated using CSU-RAMS and PNU/DEM at Busan metropolitan area. The estimated values of V$_{d}$ were larger in forest and agricultural areas than water areas since ozone with low water solubility is destroyed slowly at wet surface or water.water.