북서태평양에서 열대 저기압 발생빈도의 십년간 변동 특성

최기선,김백조,이성로,박종길,Choi. Ki-Seon,Kim. Baek-Jo,Lee. Seong-Lo,Park. Jong-Kil 한국방재학회 2009 한국방재학회논문집 Vol.9 No.6

본 연구에서는 북서태평양상의 기후학적 평균 열대 저기압 발생 자료를 이용하여 이 해역의 북서구역과 남동구역에서의 열대 저기압 발생빈도의 시간변화에서 십년간 변동성을 보이고 반대 위상으로 존재함을 밝혔다. 열대 저기압 발생빈도는 북서구역에서 1980년대 중반 이후부터 최근까지(1986-2005) 증가하는 반면에, 남동구역에서 1951년부터 1970년대 초반(1951-1970)까지 높게 나타났다. 1986-2005년과 1951-1970년 사이의 차이점을 분석한 결과는 다음과 같다. i) 연직바람시어와 해수면 온도의 경우, 1986-2005년 동안에는 북서구역에서, 1951-1970년의 기간에는 남동구역에서 음의 연직시어와 양의 해수면 온도 아노말리를 나타내고 있었다. ii) 열대 저기압 이동빈도를 분석해 본 결과, 북서구역에서 발생한 열대 저기압들 중에서 1986~2005년 동안에는 주로 남중국해에 영향을 주는 빈도가 높았던 반면, 1951-1970년 동안에는 필리핀 동쪽 해상으로부터 동중국해를 지나 한국 및 일본을 통과하는 빈도가 높았다. 남동구역에서 발생한 열대 저기압들의 경우에 대략 <TEX>$150^{\circ}E$</TEX>를 기준으로 이동빈도의 공간분포가 동서로 나눠질 수 있다. 1951-1970년 동안의 열대 저기압들은 150oE의 서쪽에서, 1986-2005년 동안의 열대 저기압들은 <TEX>$150^{\circ}E$</TEX>의 동쪽에서 주로 이동하는 특성을 보였다. 특히, 1951-1970년 동안에 발생한 열대 저기압들은 필리핀의 동쪽 해상으로부터 남중국해 및 남중국 방향으로 이동하는 빈도가 높았다. iii) 두 기간 사이에 열대 저기압 이동빈도의 이러한 차이는 500 hPa 아노말리 기압패턴에 그 원인이 있다. 특히 1951-1970년 동안에는 동아시아 대륙에 저기압성 순환의 아노말리가 형성되어 필리핀 동쪽해상으로부터 동아시아 해안을 따라 남풍 아노말리가 강화되었다. 이 남풍 아노말리는 열대 저기압이 필리핀 동쪽해상으로부터 동아시아 해안을 따라 이동하기 쉽게 하는 지향류의 역할을 하였다. 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 <TEX>$150^{\circ}E$</TEX> 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.

북극진동의 위상에 따른 한국 부근에서의 태풍 활동 변화

최기선(Ki-Seon Choi),김태룡(Tae-Ryong Kim) 한국기상학회 2010 대기 Vol.20 No.4

This study shows that frequency of tropical cyclone (TC) around Korea in summer (June-September) has positive relation with Arctic Oscillation (AO) in the preceding April. In a positive AO phase, each of anomalous cyclone and anomalous anticyclone is developed in low latitude and middle latitude regions of East Asia from the preceding April to summer. As a result, while anomalous southeasterly around Korea serves as a steering flow that TCs move toward this area is strengthened, northwesterly that reinforced in southeastern area of East Asia plays a role in preventing TCs from moving toward this area. In addition, due to this distribution of pressure systems developed in this AO phase, TCs tend to occur, move and recurve in further northeastern region in the western North Pacific than TCs in a negative AO phase. On the contrary, TCs in a negative AO phase mainly move westward toward southern China or Indochina Peninsula from Philippines. Eventually, intensity of TCs is weaker than those in a positive AO phase due to the terrain effect caused by high passage frequency of TCs in mainland China.

연구논문 : 북서태평양에서 여름철 태풍활동에 대한 북태평양 진동의 영향

최기선 ( Ki Seon Choi ),이경미 ( Kyung Mi Lee ),김정윤 ( Jeoung Yun Kim ),박철홍 ( Cheol Hong Park ) 한국환경과학회 2015 한국환경과학회지 Vol.24 No.3

This study analyzed the change in tropical cyclone (TC) activity according to the fluctuation in July-to-September average North Pacific Oscillation index (NPOI) and its underlying large-scale environment during the last 37 years from 1977 to 2013. For this purpose, seven years with highest index NPOI value (positive NPOI phase) and another seven years with lowest NPOI index value (negative NPOI phase) among the 37 years were selected as sample after excluding the ENSO years. During the positive NPOI phase, TCs were created in the east of tropical and subtropical western North Pacific and moved to the west from the Philippines toward the southern region in China or toward far eastern sea of Japan. Meanwhile, during the negative NPOI phase, TCs tended to proceed to the north toward Korea or Japan passing East China Sea from the eastern sea of the Philippines. As a result, also in the TC recurvature, TCs in positive NPOI phase showed a tendency of recurving toward more eastern direction compared to TCs in negative NPOI phase. Hence, TC intensity was stronger in negative NPOI phase which allowed more time for obtaining energy from the ocean.

연구논문 : 태풍-중위도 종관 시스템 상호작용 연구: 루사(0215), 매미(0314) 사례분석

최기선 ( Ki Seon Choi ),김백조 ( Baek Jo Kim ),박종길 ( Jong Kil Park ) 한국환경과학회 2007 한국환경과학회지 Vol.16 No.9

2007년 북서태평양에서의 열대저기압 발생 특징

최기선 ( Ki Seon Choi ),김백조 ( Baek Jo Kim ),이성로 ( Seong Lo Lee ),김호경 ( Ho Kyung Kim ),박종길 ( Jong Kil Park ),이지선 ( Ji Sun Lee ) 한국환경과학회 2009 한국환경과학회지 Vol.18 No.5

한반도 여름 강우량의 변화에서 1996년을 중심으로 나타나는 남북진동 패턴

최기선(Ki-Seon Choi),오수빈(Su-Bin Oh),김도우(Do-Woo Kim),변희룡(Hi-Ryong Byun) 한국기상학회 2010 대기 Vol.20 No.2

In accordance with the time series of rainfall in summer (June, July and August) in South and North Korea for recent 28 years (1981~2008), rainfall is substantially increased in South Korea since 1996, while it is significantly decreased in North Korea. In particular, the decreasing tendency of rainfall in summer in North Korea is more definitely observed during the 2<SUP>nd</SUP> rainy season (late August - mid September) in intraseasonal variation. Such a feature is also confirmed in the spatial distribution of oscillation pattern between South and North Korea on the basis of 1996 which is obtained by empirical orthogonal function analysis using the summer rainfall observed in all weather observation stations in South and North Korea. For the decreasing tendency of rainfall in North Korea, it is found that northeasterlies from anticyclonic circulation centered on around Baikal Lake weaken convective activity during summer. On the contrary, the increasing tendency of rainfall in South Korea is related to the strengthened cyclonic circulation in the southern region of China and accordingly, enhances southwesterlies in South Korea.

동아시아의 30 °N 부근에서 여름철 태풍 강도변화

최기선 ( Ki Seon Choi ),김백조 ( Baek Jo Kim ),이성로 ( Seong Lo Lee ),김호경 ( Ho Kyung Kim ),이지선 ( Ji Sun Lee ) 한국환경과학회 2009 한국환경과학회지 Vol.18 No.10

In this paper, changes in the intensity (e.g., central pressure and maximum sustained wind speed) of Tropical Cyclone (TC) in summer in the regions located at 30 °N in East Asia from 1988 to 1991 were found. The intensity of TC from 1991 to 2007 was much higher than that of TC from 1965 to 1988. The reason for this was that the frequency of TCs passing China from 1991 to 2007 was much lower than that of TCs from 1965-1988 because a northeasterly wind caused by high-pressure circulation in East Asia got severer along the East Asian coast. Instead, TCs moved from the eastern region of the Tropical West Pacific to Korea and Japan mainly after passing the East China Sea due to the low-pressure circulation strengthened in the subtropical waters of East Asia. In addition, low Vertical Wind Shear (VWS) was created along the mid-latitude regions of East Asia and the main path of TCs from 1991 to 2007. Most of the regions in the Northwestern Pacific showed higher Sea Surface Temperature (SST) from 1991 to 2007, and had a good environment where TCs were able to maintain a higher intensity on the mid-latitude. In particular, a low sensible heat flux occurred due to high snow depth in East Asia in the spring of 1991 to 2007. Accordingly, the lower layer of East Asia showed high-pressure circulation, and the sea surrounding East Asia showed low-pressure circulation. Thus, the typical west-high, east-low pattern of winter atmospheric pressure was shown. The possibility of snowfall in East Asia in spring to be used as a factor for predicting the summer intensity of TC in the mid-latitude regions of East Asia was insinuated. The characteristics of TC in a low-latitude region were the same in Korea. The latest intensity of TCs got higher, and the landing location of TCs gradually changed from the west coast to the south coast.

한국 여름가뭄과 북서태평양 태풍활동의 연관성

최기선(Ki-Seon Choi),김도우(Do-Woo Kim),변희룡(Hi-Ryong Byun) 한국기상학회 2008 대기 Vol.18 No.4

In the tropical western Pacific (especially, west of l35°E, including South China Sea and the Philippines), during boreal summer, it was found that a strong correlation exists between the tropical cyclone activity and the drought conditions in Korea. During the summer drought, firstly, there were strong ascending flows over the tropical western Pacific with more tropical cyclone genesis, and to compensate for this, descending flows develop in the mid-latitudes, thereby causing drought; in other words, a secondary circulation is formed between the tropical western Pacific and mid-latitudes of East Asia. Secondly, the developments of both the subtropical western Pacific high and the Manchurian low are suppressed. As a result, both the land-sea pressure gradient and the southerly flow trom low-latitudes to Korean area are also weakened, which reduces approaches of tropical cyclones to this area despite the high frequency of their geneses.

한국 5월 가뭄과 북태평양진동의 연관성

최기선(Ki-Seon Choi),김도우(Do-Woo Kim),이지선(Ji-Sun Lee),변희룡(Hi-Ryong Byun) 한국기상학회 2009 대기 Vol.19 No.1

A strong negative correlation has been detected between the North Pacific Oscillation Index (NPI) and the Effective Drought Index (EDI) in May over Korea. In May of positive NPI year, anomalous patterns caused a drought in Korea as follows: the anomalous south-low, north?high low-level pressure patterns in the northeast and southeast of Korea have strengthened the anomalous northerlies to Korea. In addition, these anomalous northerlies have prevented western North Pacific (WNP) high from moving northward. As a result, anomalous descending flows have strengthened in the mid?latitude region in East Asia. In the WNP, the anomalous south?high, north?low sea surface temperature (SST) has been widely distributed, which has strengthened anomalous south?low, north?high low?level pressure patterns. These anomalous characteristics of pressure and SST patterns observed in May of positive NPI years have already been detected in previous winter (December?February) and early spring (March, April). In addition, the anomalous negative sea ice concentration in the North Pacific during two seasons has strengthened the anomalous anticyclonic circulation in the same region and in turn made a contribution to formation of anomalous south?low, north?high pressure patterns in May.

한반도 Warm Season의 시종 및 이와 연관된 기후의 장기 변동

최기선(Ki-Seon Choi),변희룡(Hi-Ryong Byun) 한국기상학회 2005 Asia-Pacific Journal of Atmospheric Sciences Vol.41 No.-