• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.276-276
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• 2023

미국의 열대저기압(tropical cyclone)은 강풍, 폭우, 해일 등의 위험을 동반하는 기후와 관련된 자연재해다. 여러 연구에 따르면 열대저기압이 동반하는 강우는 해안과 내륙지역에서의 홍수로 이어지며 인명피해 및 경제적 손실의 주원인인 것으로 조사되었다. 최근 열대저기압이 동반하는 강우와 해안지역에서 열대저기압의 이동 특성과 관련하여 다양한 연구가 진행되고 있다. 또한, 열대폭풍(tropical storm)은 열대저기압에 비해 바람세기의 등급은 낮지만 비교적 많은 양의 강우를 동반하는 경우가 많았다. 따라서, 본 연구에서는 미국 남동부에서 1979년부터 2021년 사이에 발생한 열대폭풍이 동반한 극한강우와 열대폭풍의 이동 특성을 관련지어 분석하였다. 열대폭풍 보다 높은 등급의 사상에 대한 이동 경로, 거리, 속도 등의 자료를 얻기 위해 HURDAT2를 이용하고, 열대폭풍의 이동과 중심반경에 따른 강우자료를 얻기 위해 NLDAS-2와 시공간분석을 수행하였다. 분석결과, 2000년도를 기준으로 과거기간(1979-2000년)과 현재기간(2000-2021년)에 대하여 열대폭풍의 해안과 내륙지역 이동에 따른 극한강우의 경향성과 변동추세 및 강우 특성을 확인할 수 있었다. 본 연구는 열대폭풍의 이동에 따른 극한강우의 특성을 이해하는데 유용한 정보로 활용될 것으로 예상된다.

• 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.

• 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 the Korean earth science society
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• v.30 no.6
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• pp.721-733
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• 2009

A pattern of tropical cyclone (TC) movement in the western North Pacific area was studied using the empirical orthogonal function (EOF) and the best track data from 1951 to 2007. The independent variable used in this study was defined as the frequency of tropical cyclone passage in 5 by 5 degree grid. The $1^{st}$, $2^{nd}$ and $3^{rd}$ modes were the east-west, north-south and diagonal variation patterns. Based on the time series of each component, the signs of first and second mode changed in 1997 and 1991, respectively, which seems to be related to the fact that the passage frequency was higher in the South China Sea for 20 years before 1990s, and recent 20 years in the East Asian area. When the eigen vectors were negative values in the first and second modes and TC moves into the western North Pacific, TC was formed mainly at the east side relatively compared to the case of the positive eigen vectors. The first mode seems to relate to the pressure pattern at the south of Lake Baikal, the second mode the variation pattern around $30^{\circ}N$, and the third mode the pressure pattern around Japan. The first mode was also closely related to the ENSO and negatively related to the $Ni\tilde{n}o$-3.4 index in the correlation analysis with SST anomalies.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.23-29
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• 2022

Although tropical cyclones with wind speeds weaker than 17 ms^-1 (weak tropical cyclones: WTCs) can cause significant damage, particularly over the Seoul metropolitan area, only a few studies have focused on WTC activity over South Korea. In this study, we found that WTC activity is likely associated with the Pacific Decadal Oscillation (PDO). During the negative phases of the PDO, landfall frequency of WTCs increased significantly compared to the positive phases at 95% confidence level. When related to the negative phases of the PDO, a positive relative vorticity anomaly is found in the northern sector of the western North Pacific while a negative relative vorticity anomaly and enhanced vertical wind shear prevail in the southern sector of the WNP. These factors are favorable for the northward shift of the genesis location of tropical cyclones on average, thereby reducing the total lifetime of WTCs. Moreover, a high-pressure anomaly over the Japanese islands would shift a tropical cyclone track westward in addition to the landfall location. Consequently, the effects of the topographical friction and the Yellow Sea Bottom Cold Water on a tropical cyclone may increase. These conditions could result in a weaker lifetime maximum intensity and landfall intensity, ultimately resulting in WTCs becoming more frequent over South Korea during the negative phases of the PDO.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.193-199
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• 2006

This article reviews several microwave instruments employed in observation and analysis of tropical cyclones (TCs), typhoon, and hurricanes. Microwave signals are useful for observing tropical cyclones with severe storms since it isn't severely absorbed by the clouds and rain in the storm. The instruments discussed include scatterometers, microwave radiometers, synthetic aperture radars (SARs), and rain radar from space. The date such as winds, rainfall and cloud-distribution in the TCs obtained by microwave instruments provide important informations for forecasting the intensity and path of the typhoon. For example, there're wind-distribution provided by SSM/I which has a wide swath, detailed wind fields from ERS-1, 2 scatterometers and RADARSAT-1 SAR and TRMM's rain radar pro 떠 ding high resolution. Operational satellite instruments lunched recently have improved upon the problems of low resolution and narrow swath indicated at the beginning microwave remote sensing. Understanding and practical using sufficiently about the microwave instruments will serve for searching the features such as generation and development of the TCs.

• 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.

• 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.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.24-24
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• 2017

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1993.07a
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• pp.175-177
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• 1993

열대성 저기압에 의해 발생되는 태풍 또는 폭풍은 주변해역에 평균수위상승(setup)을 유발하며 진행하게 된다. 우리나라에는 주로 하절기에 남해평양에서 발생한 해풍의 영향을 받아 해일 등의 피해를 입게 되는데, 이러한 해일은 여러가지 수위상승효과가 복합된 결과이다. 즉, 폭풍 도착전 발생하는 초기수위상승(initial setup), 저기압 중심 주변의 급격한 압력경사에 의한 수위상승(pressure setup), 폭풍의 진행속도가 발생된 파의 속도에 근접할 경우 압력차에 의한 수위상승이 더욱 증폭되는 장파수위상승(long wave setup), 바람과 바닥 마찰에 의한 수위상승(wind and bottom stress setup), Coriolis힘에 의한 수면상승(Coriolis setup) 등 여러 가지 효과에 의해 해일이 발생하게 된다. (중략)