• 한국방재학회 논문집
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• 제9권4호
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• pp.37-44
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• 2009

본 연구에서는 1970년부터 2008년까지 연중 강풍 발생이 많은 지역인 군산, 목포, 여수, 완도에서 관측된 시간별 평균 바람자료를 이용하여 원인별 강풍발생특성을 분석하였다. 기상청 강풍주의보 기준인 13.9 m/s 이상인 바람을 강풍으로 정의하였다. 강풍 발생 원인을 태풍, 겨울 계절풍, 전선풍으로 구분하였다. 태풍의 경우 관측지점 상륙을 전후로 급격한 풍향 및 풍속의 변화를 나타냈고, 겨울 계절풍의 경우에는 북서풍 계열이 우세하며 풍속의 주기성을 보였다. 전선풍은 전선의 위치에 따라 관측지점의 풍향이 남서풍 계열에서 북서풍 계열로 변화하였다. 강풍의 발생빈도는 군산, 목포, 여수, 완도의 순이었고, 발생 원인별로 겨울 계절풍은 군산과 목포, 완도에 가장 영향이 크고, 태풍의 영향이 가장 적었으며, 여수는 태풍에 의한 영향이 가장 많고 겨울 계절풍의 영향이 가장 적었다. 지구온난화와 연관된 강한 태풍의 발생은 매년 태풍의 수가 일정함에도 불구하고 강풍 발생빈도를 증가시켰으며, 겨울 계절풍과 전선풍에 의한 빈도는 점차 감소하는 경향을 보였다. 강풍의 지속시간의 결과에서는 각 발생원인 모두 1시간 지속시간의 비율이 가장 높고, 시간이 증가할수록 빈도는 감소하였다. 이러한 결과는 각 지점의 지리적 위치에 의한 영향이 크게 반영되어 나타났다.

• Ocean and Polar Research
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• 제27권3호
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• pp.289-297
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• 2005

The change in global climate and Asian monsoon patterns during the mid-Holocene, 6000 years before present (6 ka), is simulated by a climate model at spectral truncations of T170 with 18 vertical layers, corresponding to grid-cell sizes of roughly 75km. The present simulation is forced with the observed monthly data of sea surface temperatures, and the specified concentration of atmospheric carbon dioxide, while in the mid-Holocene experiment, orbital parameters such as obliquity, precession, and eccentricity are changed to the 6ka conditions. Under such conditions, the precipitation associated with the summer monsoon is enhanced over a wider zonal band from the Middle East to Southeast Asia, while no significant alteration takes Place in winter. The monsoonal wind also increases over the Arabian Sea, showing the enhanced southwesterly wind during summer and northeasterly wind during winter. Overall, the showing of the Asian monsoon is enhanced during the mid-Holocene, especially in summer, which is consistent with the proxy estimates and other previous model simulations.

• Asia-Pacific Journal of Atmospheric Sciences
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• 제54권4호
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• pp.545-561
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• 2018

Over the North East Asia, extreme anomalous precipitation were observed in 2013 and 2014. During 2013 summer the precipitation was found to be higher (two standard deviation) than the climatological mean of the region; whereas during 2014, which was a borderline El Ni?o year, precipitation was found to be lower (one standard deviation). To understand the differences of these two anomalous years the Global/Regional Integrated Model system (GRIMs) has been used. The study found that low landsurface temperature and high sea-surface temperature over ocean caused a smaller land-sea contrast of surface temperature between East Asia and North West Pacific Ocean in 2014, which could have caused an eastward shift of mean monsoon circulation in that year compared to the circulation in 2013. Due to a change in the lower level circulation and wind field over East Asia the evaporation and moisture transport patterns became very different in those two years. In 2013, this study found high latent heat flux over Eastern China, which implies an increased surface evaporation over that region, and the moisture transported to the north by the mean monsoon circulation; whereas, there was no correlated transport of moisture to the North East Asia during 2014. The precipitable water over North East Asia has a stronger correlation with the latent heat flux over southern land region than that from Ocean region in the eastern side in both the years. A new approach is proposed to estimate the sub-grid scale hydrometeors from GRIMs, overestimated in the existing model.

• Ocean and Polar Research
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• 제24권1호
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• pp.1-18
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• 2002

Seasonal variation in global transport calculated from an ocean general circulation model (OGCM) has been assessed through the comparison with observational estimates. The OGCM based on the GFDL MOM1.1 has honzontal grid interval of 10 and 21 verticle levels, and was integrated for 31 years forced by climatological wind stress, freshwater flux, and heat flux with restoring. General features of the world ocean circulation are well reproduced, which include the western boundary currents such as the Kuroshio and the Agulhas Current, the Equatorial Current system, the Antarctic Circumpolar Current, and the Weddell Sea gyres. Also well resolved is the remarkable seasonal variation in the depth-integrated flows in the northern Indian Ocean due to the monsoonal wind. Monthly variation is found to be dominant in the transport of the Antarctic Circumpolar Current through the Drake Passage in accordance with observational estimates. It has been shown that the mid-latitude depth-integrated flows obey the Sverdrup relation, except for some regions such as continental shelf regions where the interaction between stratification and bottom topography is critical.