• Journal of the Korean earth science society
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• v.33 no.4
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• pp.337-349
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• 2012

In this study, we classify the 1000 hPa geopotential height fields around the Korean peninsula through the Kmeans cluster analysis and investigate the occurrence characteristics of each cluster pattern. The 11 clusters are identified as the typical pressure patterns, applying the pattern correlation as a similarity among clusters and the criterion of cluster similarity 0.8, of which three pressure patterns are associated with the extension of Siberia air mass, other three with the latitudes of the longest symmetry axis of North Pacific highs, two with the trough largely under the air mass of Siberia or North Pacific, and the remaining three, the migratory high patterns generally occurring in spring and autumn, are disjointed according to the direction of the longest symmetry axis of highs. The occurrence rate of air masses affecting the Korean peninsula, estimated from the number of occurrence days of 11 pressure patterns, is 55.4% Siberian, 29.3% North Pacific, 12.8% Yangtze-River, 2.5% Okhotsk sea and 68.2% of all these is the continental air masses. The wintertime pressure patterns around the Korean peninsula are nearly contrary to those in summertime, each dominated by the highs extended from the stationary air masses over the Central Siberia and the North Pacific ocean. The migratory highs occur largely in spring and autumn while transferring from the wintertime patterns to summertime patterns, or vice versa. Recently, the occurrence frequency of the highs extended from the North Pacific is on the decrease and while the wintertime pressure patterns occur frequently in spring and autumn, the occurrence frequency of the pressure patterns with trough is on the increase and the migratory highs occur in nearly all seasons.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.49-58
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• 2012

Through a statistical change-point analysis, this study found that Korea landfalling tropical cyclone (TC) frequency has increased rapidly since 1981. This increase is due to the following phenomenon. When anomalous cyclone is developed in the East Asian continent, anomalous anticyclone is reinforced in the western Pacific, which is related to the eastward shift of western North Pacific high, and thus anomalous southerly is formed to Korea from low-latitudes. This anomalous southerly plays an important role as steering flow in moving TCs toward Korea. To examine the cause of the development of anomalous cyclone in the East Asian continent, this study analyzed the water equivalent of accumulated snow depth during the preceding spring (March to May). As a result, less snow depth is observed in most regions of the East Asian continent than before 1981. Therefore, anomalous cyclone in the East Asian continent in summer can be reinforced by the land heating from the preceding spring and then the steering flow of anomalous southerly that moves TCs toward Korea can be also developed to Korea from low-latitudes in summer.

• Journal of the Korean earth science society
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• v.34 no.4
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• pp.336-344
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• 2013

This study has developed a multiple linear regression model (MLRM) for the seasonal prediction of the summer tropical cyclone genesis frequency (TCGF) over the western North Pacific (WNP) using the four teleconnection patterns. These patterns are representative of the Siberian high Oscillation (SHO) in the East Asian continent, the North Pacific Oscillation (NPO) in the North Pacific, Antarctic oscillation (AAO) near Australia, and the circulation in the equatorial central Pacific during the boreal spring (April-May). This statistical model is verified by analyzing the differences hindcasted for the high and low TCGF years. The high TCGF years are characterized by the following anomalous features: four anomalous teleconnection patterns such as anticyclonic circulation (positive SHO phase) in the East Asian continent, pressure pattern like north-high and south-low in the North Pacific, and cyclonic circulation (positive AAO phase) near Australia, and cyclonic circulation in the Nino3.4 region were strengthened during the period from boreal spring to boreal summer. Thus, anomalous trade winds in the tropical western Pacific (TWP) were weakened by anomalous cyclonic circulations that located in the subtropical western Pacific (SWP) in both hemispheres. Consequently, this spatial distribution of anomalous pressure pattern suppressed convection in the TWP, strengthened convection in the SWP instead.

• 한국방재학회:학술대회논문집
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• 2010.02a
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• pp.115.1-115.1
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• 2010

본 연구에서는 1980년부터 2008년까지 CRED 자료를 이용하여 북한의 자연재해 발생 특성과 피해 현황을 조사하였다. 북한의 자연재해는 주로 여름철 태풍과 홍수에 의해 발생하였으며, 대표적인 홍수사례는 1995년과 2007년이다. 또한 북한의 홍수 발생과 관련된 종관기상상태를 알아보기 위하여 위성영상과 일본기상청 제공 인쇄일기도를 활용하였다. 북한의 홍수와 관련된 호우는 장마전선의 영향, 북서쪽에서 접근하는 저기압의 서해상에서 발달, 북태평양 고기압의 가장자리에서 대류 불안정, 그리고 열대성 저기압(태풍)의 소멸과 관련하여 발생하였다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.52-55
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• 2006

최근 54년($1951{\sim}2004$년) 동안 한반도 상륙태풍에 대한 기후학적 특성 분석이 이루어졌다. 한반도 상륙 및 영향 태풍의 빈도는 1980년대 후반 이후 급격하게 증가하였다. 한반도에 상륙하는 태풍의 진로 또한 변화하였다. 과거에는 한반도 서해안의 중 북부지역에 상륙하여 동해를 지났으나, 최근 들어 남해안에 상륙하여 동해로 지나가는 진로가 두드러졌다. 이는 전향점이 최근 들어 남동쪽으로 이동하였기 때문이다. 결국 한반도 상륙 태풍의 진로 및 전향점이 남동쪽으로 이동한 것은 북태평양 고기압이 동쪽으로 이동하는 추세와 관련이 있었다.

• Journal of the Korean earth science society
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• v.34 no.2
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• pp.136-147
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• 2013

This study examined the effect of the Antarctic Oscillation (AAO) in June on the June rainfall in Korea by using a correlational statistical analysis. Results showed that there is a highly positive correlation between the two variables. In other words, the June rainfall in Korea is influenced by the Mascarene High and Australian High that are strengthened in the Southern Hemisphere, which is a typical positive AAO pattern. When these two anomalous pressure systems strengthen, the cold cross-equatorial flows in the direction from the region around Australia to the equator are intensified, which in turn, force a western North Pacific subtropical high (WNPSH) to develop northward. This pressure development eventually drives the rain belt to head north. As a result, the Changma begins early in the positive AAO phase and the June rainfall increases in Korea. In addition, a WNPSH that develops more northward increases the landfall (or affecting) frequency of tropical cyclones in Korea, which plays an important role in increasing the June rainfall.

• Journal of the Korean association of regional geographers
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• v.5 no.1
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• pp.151-162
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• 1999

This study is a comparative analysis of sea level and 500hPa surfaces between dry year and wet year, which are selected by variability of precipitation and standardized anomalies in Korea in early autumn. While the amount of precipitation of early autumn decreases, the variability of precipitation increases rapidly reflecting the strength and weakness of Kaul Changma front and the occurrences of the typhoonic precipitation. The regional distribution of the variability of precipitation shows west-high, east-low pattern in which the east coast and the southeastern coast shows low, but high in the southwestern coast. In the anomalies distribution of sea-level and 500hPa surfaces, during dry year, the northern part of Siberia and the core area of North Pacific high shows negative anomalies, on the contrary, there were positive anomalies in wet year at the same areas. In addition, at the 500hPa level, while the Korean peninsula was located at the west of deep trough with low zonal index in dry year, the peninsula was influenced by weak trough with high zonal index showing strong zonal flow in wet year. During dry year the height of 500hPa surface is low at the north of $40^{\circ}N$, but high in wet year. In consequences, this study identified that the occurrences of dry year and wet year were influenced by the seasonal variations of the strength and the weakness of North Pacific high and Siberian high.

• Journal of the Korean earth science society
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• v.23 no.4
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• pp.369-379
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• 2002

The characteristics of the East Asian summer monsoon circulation associated with the cool and wet summer of 1993 and the warm and dry summer of 1994 are investigated by analyzing the atmospheric circulations features in the upper and lower troposphere and by examining the global SST and associated tropical convective precipitation fields. The negative geopotential height anomalies at 500 hPa and 200 hPa in 1993 over East Asia, the central North Pacific, and the western United States were replaced by positive ones in 1994. In addition, the 200 hPa zonal wind anomaly averaged over the East Asian summer monsoon region is negatively correlated with the Korean summer temperature anomaly. The subtropical jet stream in 1993 was displaced into the central part of Korea well south of its normal position. The western Pacific subtropical high was shifted southward, and the East Asian summer rainfall and temperature was above-normal and below-normal, respectively due to the southwestward extension of a cold and dry polar airmass from the Sea of Okhotsk to the Est Sea. In contrast, the subtropical jet stream in 1994 was displaced well north of its normal position. The abrupt northward shift of the western Pacific subtropical high was accompanied with the rapid northward movement of the rain band of the East Asian summer monsoon rainfall. The anomaly patterns of the East Asia summer rainfall and temperature were opposite to those of 1993. Large sea surface temperature anomalies of opposite signs existed in the tropical Pacific with a mature El $Ni{\~{n}o$ in 1993 and a weak La $Ni{\~{n}a$ condition in 1994. The role of the anomalous convective precipitation in the western Pacific and the Indian Ocean related with the variations in the low-level cross-equatorial flow along the northwestern periphery of the Australian high and the Mascarene high is probably to influence a large-scale atmospheric circulation over the East Asia during both the years.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.21-29
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• 2010

In this study, characteristics of natural disaster and damage in North Korea are examined by using CRED(Centre for Research on the Epidemiology of Disasters) data from 1980 to 2008. Result shows that most natural disasters are caused by summertime typhoon and floods with typical floods of 1995 and 2007. Also, synoptic weather condition associated with heavy rainfall in North Korea is analyzed by using satellite image and weather chart provided by JMA(Japan Meteorological Agency). The heavy rainfalls associated with flood in North Korea are mainly related to the effect of Changma front, abrupt development of southeastward moving low over Yellow Sea, convective instability at the edge of North Pacific high and passage of weakened tropical cyclone(typhoon).

• Journal of the Korean Geographical Society
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• v.41 no.1 s.112
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• pp.94-105
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• 2006

This paper aims to analyze changes of unusual temperature events on summer and winter and their controlling factors. There has been obviously an increased frequencies of summer unusual high temperature occurrence and decreased frequencies of winter unusual low temperature at most of stations. WMI, winter SHI and AOI might be essential for prediction of unusual temperature during winter and summer OHI and spring NPI for summer unusual low temperature. These factors are crucial because they reflect the recent global warming trend as well as have apparent associations with unusual temperature occurrence frequency in Korea.