• 한국환경과학회지
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• 제18권10호
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• pp.1089-1101
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• 2009

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 $30^{\circ}N$ 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.

• 한국해양학회지
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• 제20권1호
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• pp.12-21
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• 1985

하계 동지나해에서 가장 중요한 해양학적 현상들을 재검토하였다. 계절적 수 온약층 상부 표층수는 태양가열과 주로 양자강으로 부터의 담수의 유입 그리고 하 계 계절풍에 의해 지대한 영향을 받고 있다. 수온약층 하부층에는 여러가지 해양역 학적 작용에 대한 질량장의 조정에 의해서 몇가지 분명히 구별되는 수괴들 즉 쿠로 시오 표층수, 서북태평양 중앙수, 황해저층 냉수등이 잠입되고 있다. 잠입된 황해저 층 냉수와 서북태평양 중앙수와의 전선역 혼합이 제주 남방 대륙붕상의 저층에서 일어난다. 이 혼합수는 제주 주변과 한국 남해안 중저층의 해수 특성에 커다란 영 향을 미칠 것으로 보인다.

• 한국수산과학회지
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• 제35권1호
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• pp.46-56
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• 2002

황해남부해역에 근원을 갖고 있는 저온 $\cdot$ 저염의 저밀도수가 춘계인 1998년 3월 중순부터 4월 초순까지 표층에서부터 약 20m층까지 분포하며 연취되는 북서계절풍에 편승하여 제주도 연안천해역으로 Ekman 수송되어 제주도 북부 연안천해역에 영향을 미쳤다. 따라서 이러한 자료의 축적을 통하여 해양환경의 Realtime monitoring을 위한 기초자료의 제공과 어$\codt$해황예보의 정도를 향상시킬 수 있는 중요한 자료를 제공하게 된다.

• Ocean and Polar Research
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• 제29권4호
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• pp.311-316
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• 2007

Ocean noise may be used for monitoring wind speed and rainfall rate on the sea surface, as well as for tracking whales' migration routes. In particular, low-frequency ocean noise has recently been of concern with relation to the behavior of marine mammals. Low-frequency ocean noise has been increasing over the past few decades due to increase of ship traffic and offshore oil industry activities. Mechanical noise such as flow noise and cable strumming noise may be induced if low-frequency ocean noise is measured by cabled traditional hydrophone in high current areas. To successfully measure low-frequency ocean noise in a shallow water environment with strong current, we developed a self-recording hydrophone. This paper describes the main configurations of the self-recording hydrophone and presents some results on measured data.

• 한국해안해양공학회지
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• 제7권4호
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• pp.379-392
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• 1995

대한해협의 유황, 표류 예측모형을 수립하기 위한 초기노력을 수행하였는데 첫 대상해역은 대한해협주변해역으로 하였다. 해류의 요인별 Data Table에 의거한 시공적 유황예측에 의한 표류예측 시뮬레이션을 수행하여 이 해역에서 관측된 위성추적부표의 결과와의 비교로서 모형의 검증을 수행하였는데 비교적 좋은 일치를 보였다.

• 대기
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• 제26권2호
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• pp.277-288
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• 2016

Polar lows are intense mesoscale cyclones that mainly occur over the sea in polar regions. Owing to their small spatial scale of a diameter less than 1000 km, simulating polar lows is a challenging task. At King Sejong station in West Antartica, polar lows are often observed. Despite the recent significant climatic changes observed over West Antarctica, adequate validation of regional simulations of extreme weather events such as polar lows are rare for this region. To address this gap, simulation results from a recent version of the Polar Weather Research and Forecasting model (Polar WRF) covering Antartic Peninsula at a high horizontal resolution of 3 km are validated against near-surface meteorological observations. We selected a case of high wind speed event on 7 January 2013 recorded at Automatic Meteorological Observation Station (AMOS) in King Sejong station, Antarctica. It is revealed by in situ observations, numerical weather prediction, and reanalysis fields that the synoptic and mesoscale environment of the strong wind event was due to the passage of a strong mesoscale polar low of center pressure 950 hPa. Verifying model results from 3 km grid resolution simulation against AMOS observation showed that high skill in simulating wind speed and surface pressure with a bias of $-1.1m\;s^{-1}$ and -1.2 hPa, respectively. Our evaluation suggests that the Polar WRF can be used as a useful dynamic downscaling tool for the simulation of Antartic weather systems and the near-surface meteorological instruments installed in King Sejong station can provide invaluable data for polar low studies over West Antartica.

• 대기
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• 제22권4호
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• pp.483-488
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• 2012

The monsoon front lies on East Asian region, but it gradually propagates to the north during the boreal summer. The equivalent potential temperature (EPT) reveals the thermodynamical features of air masses and monsoon front. Therefore, this study considered the thermodynamical EPT and dynamical wind fields to clarify the peculiarity of East Asian summer monsoon (EASM) variations in June and July, respectively. Western North Pacific subtropical high (WNPSH) and Okhotsk sea high (OSH) both play the crucial role to interannual variations of EASM frontal activity and amount of rainfall. The OSH is important in June, but the WNPSH is key factor in July. Furthermore, the OSH (June) is affected by North Atlantic tripolar sea surface temperature (SST) pattern and WNPSH (July) is influenced by North Indian Ocean SST warming.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.317-322
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• 2002

Dramatic changes in the patterns of satellite-derived pigment concentrations, sea-level height anomaly, sea surface temperature anomaly, and zonal wind anomaly are observed during the 1997-1998 El Nino. By some measures, the 1997-1998 El Nino was the strongest of the 20$^{th}$ century. A very strong El Nino developed during 1997 and matured late in the year. A dramatic recovery occurred in mid-1998 and led to a La Nina conditions. The largest spatial extent of the phytoplankton bloom was followed recovery from El Nino over the equatorial Pacific. The evolution towards a warm episode (El Nino) continued in the equatorial Pacific from March 2002 and further development toward mature El Nino conditions may be possible in late 2002. The OSMI (Ocean Scanning Multispectral Imager) data can be used for detection of dramatic changes in the patterns of pigment concentration during next El Nino.

• 한국대기환경학회지
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• 제7권3호
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• pp.169-179
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• 1991

Atmospheric $O_3$ in the biosphere is formed under the favourable meteorological condition, when the primary pollutants, such as $NO_2, HC, CO, CH_4$, etc., react with over constituents. Observed annual average concentrations for 1989 and 1990 were 11.8 and 10.4 ppb, respectively. THe number of days measured ozone over 80 ppb in Seoul were 36 in 1989 and 39 in 1990. In general, monthly maximum values occurred in May and August. In comparison with 1 $\sim$ 2 maxima of $O_3$ distribution in large cities in other countries, it was found that there were 3 $\sim$ 4 maxima in Seoul and its suburbs. Topographic effects, resulted by wind channelling in the Han River valley and by the blocking of air pollutants in the mountain, appeared to produce multiple centres of $O_3$ maxima in Seoul. Surface $O_3$ values were low with decreasing solar radiation, when the cloudiness increased and precipitation occurred. According to 12 cases examined, 2 cases shown here, $O_3$ values exceeding 80 ppb were occurred when the Korean peninsular was under the influence of the backside airflows with high intensity of solar radiation. Occasionally, sea breezes were observed to occur in warm seasons, and the chanelling effect of the Han River valley appeared to increase the general wind (speed) to the east side of Seoul. In this meso-scale situation $O_3$ in downwind is highly correlated with precursors. The sea breeze of 2 $\sim$ 4 m $s^{-1}$ will take 3 $\sim$ 5 hours to transport photochemical precursors for 20 $\sim$ 50 km. In turn the areas of maximum $O_3$ occurrence in Seoul are in the range of meso-scale transport of air pollutants.

• 대기
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• 제27권3호
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• pp.317-329
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• 2017

Ocean mixed layer (OML) depth affects diurnal cycle of sea surface temperature (SST) induced by change of solar radiation absorption and heat budget in ocean. The diurnal SST variation can lead to convection over the ocean, which can impact on localized precipitation both over coastal and inland. In this study, we investigate the OML characteristics affecting the diurnal cycle of SST for the Korean Peninsula and surrounding areas. To analyze OML characteristics, HYCOM oceanic mixed layer depth (MLD) and wind field at 10 m from ERA-interim during 2008~2016 are used. In the winter, MLD is deeply formed when the strong wind field is located on perpendicular to continental slope over deep seafloor areas. Besides, cooling SST-induced vertical mixing in OML is reinforced by dry cold air originated from Siberia. The OML in summer is shallowly distributed about 20 m. In order to estimate the impact of OML model in high resolution NWP model, four experimental simulations are performed. At this time, the prognostic scheme of skin SST is applied in NWP to simulate diurnal SST. The simulation results show that CNTL (off-OML) overestimates diurnal cycle of SST, while EXPs (on-OML) indicate similar results to observations. The prediction performance for precipitation of EXPs shows improvement compared with CNTL over coastal as well as inland. This results suggest that the application of the OML model in summer season can contribute to improving the prediction for performance of SST and precipitation over coastal area and inland.