• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.290-292
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• 2008

we applied Wind Field Module of PHRLM so that disaster prevention agency concerned can effectively estimate the possible strong wind damages by typhoon. In this study, therefore, we estimated wind speed at 300m level using 700hPa wind according to the research method by Franklin(2003), PHRLM(2003), and Vickery and Skerlj(2005). Then we calculated wind speed at 10m level using the estimated wind speed at 300m level, and finally, peak 3.second gust on surface. The case period is from 18LST August 31 to 03LST September 1, 2002, when the typhoon Rusa in 2002 was the most intense. Among disaster prediction models in the US, Wind Field Module of PHRLM in Florida was used for the 2002 typhoon Rusa case. As a result, peak 3.second gust on the surface increased $10\sim20%$ in the typhoon's 700hPa wind speed.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.195-201
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• 2008

Damage from typhoon disaster can be mitigated by grasping and dealing with the damage promptly for the regions in typhoon track. What is this work, a technique to analyzed dangerousness of typhoon should be presupposed. This study estimated 10 m level wind speed using 700 hPa wind by typhoon, referring to GPS dropwindsonde study of Franklin(2003). For 700 hPa wind, 30 km resolution data of Regional Data Assimilation Prediction System(RDAPS) were used. For roughness length in estimating wind of 10 m level, landuse data of USGS are employed. For 10 m level wind speed of Typhoon Rusa in 2002, we sampled AWS site of $7.4{\sim}30km$ distant from typhoon center and compare them with observational data. The results show that the 10 m level wind speed is the estimation of maximum wind speed which can appear in surface by typhoon and it cannot be compared with general hourly observational data. Wind load on domestic buildings relies on probability distributions of extreme wind speed. Hence, calculated 10 m level wind speed is useful for estimating the damage structure from typhoon.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.85-88
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• 2008

Damage from typhoon disaster can be mitigated by grasping and dealing with the damage promptly for the regions in typhoon track. What is this work, a technique to analyzed dangerousness of typhoon should be presupposed. This study estimated 10m level wind speed using 700hPa wind by typhoon, referring to GPS dropwindsonde study of Franklin(2003). For 700hPa wind, 30km resolution data of Regional Data Assimilation Prediction System(RDAPS) were used. For roughness length in estimating wind of 10m level, landuse data of USGS are employed. For 10m level wind speed of Typhoon Rusa in 2002, we sampled AWS point of $7.4\sim30km$ distant from typhoon center and compare them with observational data. The results show that the 10m level wind speed is the estimation of maximum wind speed which can appear in surface by typhoon and it cannot be compared with general hourly observational data. Wind load on domestic buildings relies on probability distributions of extreme wind speed. Hence, calculated 10m level wind speed is useful for estimating the damage structure from typhoon.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.23 no.1
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• pp.34-38
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• 1995

A diagnostic study on the summertime air mass thunderstorms occurring in the middle region of South Korea was made by analyzing the data of surface and upper air observations as well as the surface and upper level weather charts. The key parameters used in the present study are the amount of precipitable water below 850 hPa level, the vertical profiles of water vapor content and wind, and both the temperature difference and the equivalent potential temperature difference between 850 hPa and 700 hPa levels. It is found from this study that the summertime air mass thunderstorms in the middle region of South Korea can be classified into two distinct types, type I and type II. The thunderstorms of type I occur under the atmospheric conditions of high moisture content, low vertical wind shear in low levels, and conditional instability between 850 hPa and 700 hPa levels. On the other hand, the thunderstorms of type II occur under the atmospheric conditions of less moisture content, higher wind shear and conditional instability. Furthermore, our study suggests that atmospheric instability and the amount of water vapor below 850 hPa level are complementary in the development of air mass thunderstorms. The complementary nature between these two parameters may be an explanation for the thunderstorm development in the areas of low atmospheric water vapor content such as the plains of eastern Colorado.

• Atmosphere
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• v.31 no.4
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• pp.395-404
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• 2021

In order to investigate downslope windstorm by using more detailed observation, we observed 6 cases at 3 sites - Inje, Yongpyeong, and Bukgangneung - during "3-D Meteorological Observation Project in Yeongdong region of Gangwon province, South Korea in 2020." The results from analysis of the project data were as follows. First, AWS data showed that a subsidence inversion layer appeared in 800~700 hPa on the windward side and 900~850 hPa on the leeward side. Second, before strong wind occurred, the inversion layer had descended to about 880~800 hPa. Third, with mountain wave breaking, downslope wind was intensified at the height of 2~3 km above sea level. After the downslope wind began to descend, the subsidence inversion layer developed. When the subsidence inversion layer got close to the ground, wind peak occurred. In general, UM (Unified Model) GDAPS (Global Data Assimilation Prediction System) have had negative bias in wind speed around peak area of Taebaek mountain range, and positive bias in that of East Sea coast area. The stronger wind blew, the larger the gap between observed and predicted wind speed by GDAPS became. GDAPS predicted strong p-velocity at 0600 LST 25 Apr 2020 (4^th case) and weak p-velocity at 2100 LST 01 Jun 2020 (6^th case) on the lee-side of Taebaek mountain range near Yangyang. As hydraulic jump theory was proved, which is known as a mechanism of downslope windstorm in Yeongdong region, it was confirmed that there is a relationship between p-velocity of lee-side and wind speed of eastern slope of Taebaek mountain range.

• Journal of the Korean earth science society
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• v.36 no.4
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• pp.315-329
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• 2015

We investigated the characteristics of meteorological conditions related to the strong downslope wind over the leeward side of the Taebaek Mountains during the period 2005~2010. The days showing the strong wind exceeding $14ms^{-1}$ in Gangwon province were selected as study cases. A total of 15 days of strong wind were observed at Sokcho, Gangneung, Donghae, and Taebaek located over the Yeongdong region. Seven cases related to tropical cyclone (3 cases) and heavy snowfall (2 cases) and heavy rainfall (2 cases) over the Yeongdong region were excluded. To investigate the characteristics of the remaining 8 cases, we used synoptic weather chart, Sokcho radiosonde, Gangneung wind profiler and numerical model. The cases showed no precipitation (or ${\leq}1mm\;day^{-1}$). From the surface and upper level weather chart, we found the pressure distribution of southern high and northern low pattern over the Korean peninsula and warm ridge over the Yeongdong region. Inversion layer (or stable layer) and warm ridge with strong wind were located in about 1~3 km (925~700 hPa) over mountains. The Regional Data Assimilation and Prediction System (RDAPS) indicated that warm core and temperature ridge with horizontal temperature gradient were $0.10{\sim}0.23^{\circ}C\;km^{-1}$ which were located on 850 hPa pressure level above mountaintop. These results were summarized as a forecasting guidance of downslope windstorm in the Yeongdong region.

• Atmosphere
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• v.19 no.1
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• pp.37-51
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• 2009

Kinematic characteristics of a heavy rainfall event occurred in Changma front are analyzed using synoptic weather charts, satellite imagery and NCEP(National Centers for Environmental Prediction) / NCAR(National Centers for Atmospheric Research) reanalysis data. The heavy rainfall is accompanied with mesoscale rain clouds developing over the Southwest region of Korea during the period from 0300 LST to 2100 LST 25 June 2006. The surface cyclone in the Changma front is generated and developed rapidly when it meets following vertical conditions: The maximum value of relative vorticity is appeared at 700 hPa and is extended gradually near the surface. It is thought that the vertical structure of relative vorticity is closely related with the descent of strong wind zone exceeding $10ms^{-1}$. The jet core at 200 hPa is shifted southward and extended downward and the low-level jet stream associated with upper-level jet stream appeared at 850 hPa. Kinematic features of heavy rainfall system at cyclone-generating point are as follows: In the generating stage of cyclone, the relative vorticity below 850 hPa increased and the convergence below 850 hPa and the divergence at 400 hPa are intensified by southward movement of jet core at 200 hPa. The heavy rainfall system seems to locate to the south of the exit region of upper-level jet streak; In the developing stage of cyclone, the relative vorticity below 850 hPa and the convergence near surface are further strengthened and upward vertical velocity between 850 hPa and 200 hPa is increased.

• Journal of Environmental Science International
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• v.24 no.9
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• pp.1199-1210
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• 2015

There were 35 typhoons affecting Korean Peninsula from 1999 to 2009(The average annual number of typhoon is 3.18). Among these typhoons, the number of typhoon passing through the Yellow sea, the Southern sea and the East sea were 14, 6 and 15 respectively. Wind speed on the height of 10 m can be finally estimated using the surface roughness after we calculate wind speed on the height of 300 m from the data on the surface of 700 hPa. From the wind speeds on the height of 10 m, we can understand the regional distributions of strong wind speed are very different according to the typhoon tracks. Wind speed range showing the highest frequency is 10~20 m/s(45.69%), below 10 m/s(30.72%) and 20~30 m/s(17.31%) in high order. From the analysis of the wind speed on the hight of 80 m, we can know the number of occurrence of wind speed between 50 and 60 m/s that can affect wind power generation are 104(0.57%) and those of between 60 and 70 m/s that can be considered as extreme wind speed are even 8(0.04%).

• Atmosphere
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• v.30 no.2
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• pp.125-139
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• 2020

On 6 August 2018, heavy rainfall of daily precipitation of more than 200 mm occurred in the Yeong-dong coastal area, and especially, 1-hour precipitation of 93 mm (0251~0351 LST (local standard time) 6 August) at Gangneung station, ranked second in the history of meteorological survey of the station. In this study, this heavy rainfall case over the Gangneung area would be studied to investigate the process in which the heavy rainfall occurred. A developed ridge moved toward the Yeong-dong coastal area from the Maritime Province in Russia. The approaching of the ridge led to the northeasterly cold wind over the coastal region, causing the collision between the incoming northeasterly cold wind, and the humid and warm (convectively unstable) air located over the Yeong-dong area. This collision led to a strong convergence (maximum -206 × 10^-5 s^-1) at 925 hPa level over the vicinity of Gangneung at 0300 LST 6 August, resulting updraft of up to about 4.4 m s^-1 at 700 hPa level over the area. This strong updraft forced to lift rapidly the convectively unstable, warm and humid air layer, located over the vicinity of Gangneung, leading to the heavy rainfall (1-hour precipitation of 93 mm) over the area.

• Journal of the Korean Geographical Society
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• v.32 no.1
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• pp.31-46
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• 1997

The purposes of this paper are to classify the spatial distribution types of precipitation by making daily isohyetal maps based on the winter daily precipitation and to analyse both the distributional characteristics of precipitation during the winter in South Korea and the synoptic characteristics related to them. Also, the correspondence between the spatial distribution types of precipitation and the synoptic characteristics occuring among them is examined with regards to pressure patterns and then precipitation distribution types. In addition, the characteristics of the pressure fields and temperature fields in 850hPa, 700hPa, and 500hPa level were analysed to find out the difference between the Ullung-do type and the Ullung-do${\cdot}$Honam type, which have similar characteristics on the surface weather map. As a result, the Ullung-do area showed a high frequency of occurrence regardless of precipitation classes, the East Coast area revealed a higher frequency of occurrence in over the 5mm section, while the Honam area had high frequency of occurrence in the 1~5mm section. There are twelve distribution types of precipitation during the winter. These distribution types show clear changes according to the season. The difference in precipitation distribution between the Ullung-do type and the Ullung-do${\cdot}$Honam type has a close relationship with the aspect of the upper cold air advection rather than the direction and the speed of the wind.