• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.12 no.1
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• pp.25-30
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• 1976

In the area of the Far East Asia, cyclones are observed 157ea in winter season during the years(1966-1974). Some of them are most difficult to be forecasted due to the extreme irregulalities, have carried out synoptic analysis. The rapid development of cyclones can be attributed to the descending of cold air mass surrounding the axis of the Jet Stream due to the cyclonic rotation, and the lowering of the Jet axis. The Relationships between upper trough line and max. (or min) axis of upper air temperature on the 700mb contributes to the development of the cyclones.

• Korean Journal of Remote Sensing
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• v.12 no.2
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• pp.126-138
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• 1996

The characteristics of rapid development of the low pressure system over the East Sea from 06 to 08 Nov., 1995 has been analyzed in detail by the synoptic numerical products and satellite observations. The Low system was initially triggered the development of the baroclinic leaf cloud over the border of the northern part of Korea and China and moved eastward and then developed explosively com-ma or lambda type cloud system over the East Sea. To forecast well the general development and movement of the coastal winter cyclone over the East Sea popularly in a numerical simulation by several scientists, the large baroclinicity, continuous support of water vapor, and sequential cold outbreak over the warm sea surface have been more commonly concerned about. The cyclone which the central surface pressure was dropped 40hPa within 24 hours has often accompanied strong wind and heavy snow- or rain-fall in the winter season. In all successive observations with 12-hourly satellite imagery and analyzed meteorological variables in this period, the centers of the sea-level pressure and 500hPa geopotential height associated with this cyclone were typically illustrated by moving farther eastward using GMS combined enhanced IR images. The maxi-mum wind sustained by this system with the intensity and central pressure of tropical storm was about 60 knots with the center pressure drop of 44hPa/day similar to the North American cyclonic bomb and Atlantic storm.

• Journal of the Korean earth science society
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• v.25 no.4
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• pp.277-288
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• 2004

In this study, state of sea surface were analyzed comparatively for cases of low atmospheric pressure, which occurred in the middle area of China and moved eastward to the Korean Peninsula across the Yellow sea during April 9-12, 1999, and typhoons 'NEIL' May 1999 and 'OLGA' July 1999, which moved northward along the west coast of the Korean Peninsula. In cases of low pressure, wind speeds and phases were respectively stronger and faster in the center area than in the surrounding areas. The wave heights seem to a somewhat differing tendency from that of the wind speeds due to the influences of geometry. On the other hand, wave heights were lower under typhoon weather than under low pressures, except the instance of wave height over 5 m on Chilbal when typhoon Olga pass northward from the southern area. Storm surges also showed larger amplitudes under low pressures than under typhoons. The results suggest that wave sand storm surges may be larger for a slow passing synoptic low pressures than for a fast passing local typhoon.

• The Korean Journal of Quaternary Research
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• v.12 no.1
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• pp.17-30
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• 1998

연구지역인 대관령 서쪽 산지 사면은 진부에서 동쪽으로 고속도로를 따라 약 21km 떨어진 대관령까지이며 해발고도는 500∼900m 지형경사는 3.3%이다. 1989년 5월∼1992년 5 월에 진부에서 대관령 쪽으로 영동고속도로를 따라 진부(고도 544m) 간평기(고도 576m) 유 천리(고도 600m) 싸리재(고도800m) 대관령(고도 842m)등의 5개지점을 정하여 일 강수량을 측정하였다 각 고도별 일 강수량 자료를 기초로 한반도의 지상 기압배치형에 따른 대관령 서쪽 산지의 고도별 강수량 분포의 특성을 고찰하였다,. 이결과를 용약하면 다음과 같다. 총 강수일 258일을 지상 기압배치형(기압골, 저기압, 시베리아고기압, 장마전선, 고기압, 태풍, 오호츠크해고기압)에 따라 7가지 형으로 분류하였다, 이들중 기압골이 나타난 날이 113일로 제일 많고 오호츠크해고기압이 나타난 날은 8일로 가장적었다. 고도별 일평균 강수량은 태 풍이 나타났을 때 17,5∼54,4mm로 제일많았고 시베리아고기압이 나타났을 때는 5.9∼ 19.8mm로 제일 적었다, 대관령 서쪽 산지 사면에서 강수량이 제일 많은 고도는 대관령이고 제일적은 고도는 간평리이다, 태풍과 오호츠크해고기압이 출현한 경우는 고도가 증가할수록 강수량도 많아졌다. 간평리와 대관령 고도의 강수량 분포에 관한 사례분석(1989.5∼1991.12) 에서 기압골, 저기압, 장마전선등이 나타난 36일 시베리아고기압이 나타난 1일은 간평리가 대관령보다 강수량이 많았다.

• Journal of the Korean earth science society
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• v.29 no.7
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• pp.567-578
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• 2008

The extratropically transitioning cyclones have been shown to have a large effect on weather system in the midlatitues and cause sometimes the severe weather phenomena. However, both operational forecasting and research aspect of ET remain a significant challenge. Because it is difficult to distinguish ET stage due to obscure configuration of the cyclone itself. Furthermore, any definition of ET should not only be precise enough to satisfy the needs of the operational and research communities. Therefore, the "operational deterministic process for ET" was proposed and has been used to diagnose both structure and subsequent process of ET in 2007. In this study, it has been examined the maximum wind and SST in the 1st step, satellite image in the 2nd step, sounding in the 3rd step, surface weather chart analysis in the final step. This operational manual has allowed better monitoring and understanding of the changes in the structure as ET occurs.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.58-60
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• 2020

겨울철 온대저기압은 그 세력이 강하여 해양사고의 주요 원인이 되는 등 선박의 안전 운항에 있어서 매우 중요하다. 이 연구에서는 겨울철(2019년 12월~2020년 2월)의 기상 데이터를 이용하여 제1태평양 한대전선대 부근의 온대저기압에 대하여 분석하였다. 분석 결과는 다음과 같다. 3개월 동안에 제1태평양 한대전선대 부근에서 발생한 온대저기압은 41개이고, 그 중 8개가 현저히 발달하였다. 발생 위치 별 온대저기압은 일본 동쪽 태평양이 가장 많았고(16개), 그 다음은 우리나라 주변, 동중국해, 일본 남쪽 해상 순이었다. 이동경로는 크게 5개로 구분할 수 있는데, 공통적으로 북동진하는 패턴을 보였다.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.947-956
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• 2007

In this article, the extratropical transition (ET) of tropical cyclone (TC) was investigated based on the case study covering the latest three TCs (Shanshaa Yaki, and Soulik) associated with ET evolution (onset and completion) using the objective 37 diagnostics of Evans and Hart (2003) and Hart (2003). At 500-hPa level, on an onset of ET, all three TCs entered the baroclinic zone. In a vertical cross-section analysis, three TCs before and at an onset of ET kept warm and humid throughout all levels around the TC center. However, these TCs after ET onset became relatively cold and dry over the western part of TC as the typical characteristics of ET concept model. Although our case study was not sufficient, it is concluded that the diagnostics of the ET onset and atmospheric structure change associated with Evans and Hart (2003) and Hart (2003) will be useful in ET operational forecast.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.31-39
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• 2009

This study has found that there is a reverse phase with interdecadal variation in temporal variations of tropical cyclone (TC) genesis frequency (TCGF) between Northwest sector and Southeast sector, based on climatological mean tropical cyclone genesis location over the western North Pacific. The TCGF in the Northwest sector has been increased since the mid 1980s (1986-2005), while TCGF in the Southeast sector was higher until the early 1970s (1951-1970). The analysis of a difference between 1986-2005 and 1951-1970 showed results as follows: i) Through the analysis of vertical wind shear (VWS) and sea surface temperature (SST), less VWS and higher SST in the former (latter) period was located in the Northwest (Southeast) sector. ii) In the analysis of TC passage frequency (TCPF), TCs occurred in the Northwest sector frequently passed from east sea of the Philippines, through East China Sea, to Korea and Japan in the latter period, while TCs in the former period frequently has a lot of influences on South China Sea (SCS). In the case of TCs occurred in the Southeast sector, TCs in the west (east), based on $150^{\circ}E$ had a high passage frequency in the latter (former) period. In particular, TCs during the latter period frequently moved toward from the east sea of the Philippines to SCS and southern China. iii) This difference of TCPF between the two periods was characterized by 500 hPa anomalous pressure pattern. Particularly, anomalous cyclonic circulation strengthened over the East Asian continent caused anomalous southerlies along the East Asian coast line from the east sea of the Philippines to be predominate. These anomalous winds served as steering flows that TC can easily move toward same regions.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.447-452
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• 2020

Extratropical cyclone in winter season is very important in safe operation of ships because it is a major cause of marine accidents due to its strong power. In this study, we used meteorological data, to analyze extratropical cyclones occurring near the 1st Pacific polar front from December 2019 to February 2020. The analysis results are as follows. During those three months, we recorded 41 extratropical cyclones, 8 of which were remarkably developed. The central pressure of the strongest cyclone was 947hPa. The highest number of cyclones were generated in the East P acific Ocean around J apan (16), followed by the areas around Korea, the East China Sea, and the southern Sea of J apan. The cyclones followed five major tracks with a common northeast pattern. We thus concluded that the optimal route for a ship encountering an extratropical cyclone in the North P acific in winter would be south of the cyclone's center traveling eastbound and north of the center traveling westbound.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.583-595
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• 2012

The potential for tropical cyclogenesis in a given oceanic and atmospheric environments can be represented by genesis potential index (GPI). Using the 18 Coupled Model Inter Comparison Project phase 5 (CMIP5) models, the annual cycle of GPI and interannual variability of GPI are analyzed in this study. In comparison, the annual cycle of GPI calculated from reanalysis data is revisited. In particular, GPI differences between CMIP5 models and reanalysis data are compared, and the possible reasons for the GPI differences are discussed. ENSO (El Nino and Southern Oscillation) has a tropical phenomenon, which affects tropical cyclone genesis and its passages. Some dynamical interpretations of tropical cyclogenesis are suggested by using the fact that GPI is a function of four large-scale parameters. The GPI anomalies in El Nino or La Nina years are discussed and the most contributable factors are identified in this study. In addition, possible dynamics of tropical cyclogenesis in the Northern Hemisphere Pacific region are discussed using the large-scale factors.