Validation of Salinity Data from ARGO Floats: Comparison between the Older ARGO Floats and that of Later Deployments

윤용훈,이호만,장유순,Pankajakshan Thadathil 한국지구과학회 2005 한국지구과학회지 Vol.26 No.2

Continued observation of ARGO floats for years (about 4 years) makes the conductivity sensor more vulnerableto fouling by marine life and associated drift in salinity measurements. In this paper, we address this isue by making useof floats deployed in diferent years. Floats deployed in the East Sea and the Indian Ocean are examined to find outspace-time diference). A time diference of less than five days and space diference of less than 10 km are consideredfor the match-up data sets. For analysis of the salinity drift under the stable water mass, observations of the floats fromdepest water masses have been used. From the cros-check of ARGO floats in the East Sea and the Indian Ocean, it isfound that there is a systematic drift in the older float compared to later deployments. All drift results, consistently shownegative bias indicating the typical nature of drift from fouled sensors. However, the drift is much less than 0.01, thespecified accuracy of ARGO program

서해 중부 해상 대기의 연직구조 분척

윤용훈,임주연,김백조,김태희,서장원,조하만,Youn, Yong-Hoon,Lim, Joo-Yun,Kim, Baek-Jo,Kim, Tae-Hee,Seo, Jang-Won,Cho, Ha-Man 한국지구과학회 2000 한국지구과학회지 Vol.21 No.1

To search out the characteristics of the lower and the upper atmospheric vertical structure, we selected the island(Oeyoundori Ochun-myen Poryeng city Chung-Nam) as an observation site, which is thought to represent the characteristics of ocean well, and observed the vertical structure of the atmosphere by Radiosonde. By using the results of the observation, we analyzed the changes of relative humidity(RH), temperature and wind when the cyclone and the anticyclone passed and compared the results in case of each event. To compare the vertical structure of the ocean atmosphere with those of the continent we analyzed the values observed with using Radiosonde at Osan site. Through this study, we found that relative humidity changed as the cyclone and the anticyclone passed. That is, when the cyclone came, RH increased first in the upper atmosphere than in the lower and when the high came, RH in the upper decreased sharply to 10%. And the variations of relative humidity in ocean are bigger than those in continent. In the future, we plan to f d out the relation between the vapor water in ocean and continent seasonally and daily through the observation in ocean and continent at same time.

동아시아 주변해역에서의 TOPEX/POSEIDON 고도 자료와 현장 해수면 자료의 비교

윤용훈,김기현,박용향,오임상,Youn, Yong-Hoon,Kim, Ki-Hyun,Park, Young-Hyang,Oh, Im-Sang 한국해양학회 2000 바다 Vol.5 No.4

In an effort to assess the reliability of satellite altimeter system, we conducted a comparative analysis of sea level data that were collected using the TOPEX/POSEIDON (T/P) altimeter and the 10 tide gauge (TG) stations in the satellite passing track. The analysis was made using data sets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Because of strong tidal activity in the study area, treatment of tidal errors is a very critical step in data processing. Hence in the computation of dynamic heights from the Tn data, we adapted the procedures of Park and Gamberoni (1995) to reduce errors associated with it. When these T/P data were treated, the alias periods of M$_2$, S$_2$, and K$_1$ constitutions were found at 62.1, 58.7, and 173 days. The compatibility of the T/P and TG data sets were examined at various filtering periods. The results indicate that the low-frequency signal of Tn data can be interpreted more safely with longer filtering periods (such as up to the maximum selected values of 200 days). When RMS errors for 200-day low-pass filter period was compared among the whole 10 tidal stations, the values spanned in the range of 2.8 to 6.7 cm. The results of correlation analysis at this filtering period also showed a strong agreement between the Tn and TG data sets over the whole stations investigated (e.g., P values consistently less than 0.0001). According to our analysis, we conclude that the analysis of surface sea level using satellite altimeter data can be made safely and reasonably long filtering periods such as 200 days.

칠발도 Buoy자료를 이용한 해양-대기 열교환량 산출 및 파랑 특성에 관한 연구

윤용훈,홍성길,홍윤,이지연,Youn, Yong-Hoon,Hong, Sung-Gil,Hong, Yoon,Lee, Ji-Yeon 한국해양학회 1998 바다 Vol.3 No.1

Hourly meteorological data from a marine buoy ($34^{\circ}49'00"N$, $125^{\circ}46'00"E$) operated by the Korean Meteorological Agency were obtained from July, 1996 to February, 1997. From the data air-sea heat fluxes and marine meteorological characteristics around the area are estimated. The maximum outflux of sensible heat from the sea surface occurred in January (monthly mean value, 12.6 $Wm^{-2}$ and the maximum influx to the sea occurred in July (monthly mean value, 5.5 $Wm^{-2}$). This means that the sea is heated in summer while it loses its heat in winter, and that there is inequality between the absolute values of the two seasons. The outflux of the maximum latent heat occurred in November (monthly mean value, 86.5 $Wm^{-2}$) and reach a value of 300 $Wm^{-2}$, and the maximum influx occurred in July (monthly mean value, 4.6 $Wm^{-2}$). Big difference is shown in their absolute values when the wind becomes strong. The outgoing latent heat flux reaches its maximum in autumn, and it maintains the high value through the whole winter. According to the wave data analysis, the significant wave heights are larger in winter than in summer. The periods of the significant waves are 4~6 sec. In winter, waves propagated from north and northeast are dominant because of the winter monsoon, while in summer waves from south, southwest, and west are relatively frequent.

한반도 동새상에서의 Topex/Poseidon 고도자료와 현장 조위계 관측 자료의 비교연구

윤용훈,김나영,김기현,황종선,김정우 한국지구과학회 2002 한국지구과학회지 Vol.23 No.4

Long-term Variabilities of Air Temperature in the Korean Peninsula

윤용훈,오임상,박용향,안중배 한국기상학회 2004 Asia-Pacific Journal of Atmospheric Sciences Vol.40 No.3

The Incheon temperature data, which is relatively long observational record, has been used for climate variation analysis. According to our results, the climate changes observed over Korean Peninsula for the last century are similar to the global observation in many respects. First of all, the warming trend (+1.5C/100yrs) and overall evolving pattern throughout the century are quite similar to the those for globally averaged temperature. Although the amounts of temperature about three and two times larger than those of global increases, if we consider the facts that the most of global warming and the effect of urbanization have mainly occurred over mid- and high-latitudes, the amounts seem to be reasonably estimated. The results also indicate that the climate in Korea for the last century can be understood under the same framework of global warming trend. Our research has also revealed that the climate in Korea seems to endure a rapid regime shift since the early 1980s. Even though the temperature is not related with ENSO within statistically significant level, our spectral analysis shows that the interannual variability band of 1-7 years contains most of total energy (82%) and the variability with period of 2.3 years is the most dominant feature. The decadal variability containing 18% of energy has a dominant periodicity at 11.1 years. 비교적 긴 관측 기록을 가진 인천 기온자료가 기후 변화 분석에 사용 되었다. 이 연구 결과에 의하면, 지난 세기 동안 한반도에서 관측된 기후 변화는 지구 규모의 관측결과와 유사하다. 무엇보다도 온난화 경향 (+1.5C/100yrs)과 전반적인 변화 경향이 지구 평균 기온의 경향과 아주 유사하다는 것이다. 한반도에서의 온난화 경향은 지구온난화 경향 보다 2-3배 정도 크게 나타나는데 이는 온난화와 도시효과가 대부분 중, 고위도에서 일어난다는 점을 고려하면 이상한 결과가 아니다. 즉 한반도에서 지난세기 기후는 지구온난화 경향과 같은 맥락에서 이해할 수 있다. 한반도 기후는 1980년대 초기부터 급격한 변동을 보인다. 스펙트럼 분석에 의하면, 1-7년 연주기 변동성이 전체에너지의 82%를 차지하며 그중에서 2.3년 주기의 변동성이 가장 우세하다. 나머지는 11.1년의 주기성을 갖는 10년 주기 변동성에 의해 설명된다.

이상 해수면 변동 예측을 위한 영상 표출 시스템 구축

윤용훈,서장원,한주영 한국기상학회 1999 한국기상학회 학술대회 논문집 Vol.1999 No.-

태풍의 이동경로에 따른 해일 발생 양상

윤용훈,김충기,김우규 한국해양환경·에너지학회 1998 한국해양환경·에너지학회 학술대회논문집 Vol.1998 No.-

한반도 주변 연안의 조석 예보

윤용훈,서장원,김충기,이현정 한국기상학회 1999 한국기상학회 학술대회 논문집 Vol.1999 No.-

황해 저층냉수의 특성과 남하에 대한 재조명

윤용훈,박용향,봉종헌 한국지구과학회 1991 한국지구과학회지 Vol.12 No.1

Based on a precise analysis of the long-term(1971-1984) hydrographic and wintertime air temperature data gathered in the middle and southern yellow Sea, and together with other supplimentary data from Gteratures, water characteristics of the Yellow Sea Bottom Cold Water(YSBCW) and its southward extension are reexamined ; the influence of the wintertime air temperature on the YSBCW temperature and on its spatial distribution also discussed. It was found that the hitherto defined water characteristics (T, S) of the YSBCW restrict especially the upper limit of salinity to too lower values compared to the real situation, so they are not adequate to describe the spatial distribution of the water and its southward extension phenomenon. From the present study, the southward extention of the YSBCW through the cold water through west off Chejudo from spring to summer is found highly possible ; it is strongest is April and it can be detected until August. In consequence of such a southward advection of the bottom cold water, the water temperature at 50m depth in the cold water through west off Chejudo shows its lowest values in April, with a mean temperature increase by 0.4℃ only from April to August(compared to 4℃ increase near the axis of the Yellow Sea embayment). The frequently observed cold water mass from the west to the southwest(near 32°N, 126°E)off the island during spring and summer is connected with and influenced profoundly by the bottom cold water from the southern Yellow Sea, showing almost same water. characteristics as those of the latter ; it preserves quite well its wintertime water characteristics until summer. Therefore it seems to be quite reasonable to include this cold water mass(found west to southwest off Chejudo) in the definition of the YSBCW. Here, we have suggested a new definition of the YSBCW : T$lt;12℃, 32.2$lt;S$lt;33.5‰ With this new definition, the spatial distribution of the YSBCW from the offshore of the Shandong peninsula to the southwestern area off Chejudo as well as its southward extension from spring to summer can be adequately described. The wintertime air temperature is one of the most important meteorological factors, controlling the summertime water temperature of the YSBCW and its spatial distribution. In other words, the bottom cold water formed during a severe cold winter exhibits in summer lower temperatures and also wider spatial distribution toward the coasts and to the south than that formed during a mild winter.