• Fisheries and Aquatic Sciences
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• 제10권3호
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• pp.150-158
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• 2007

Data on squid catches, water temperature, and climatic factors collected for the Northwest and subtropical North Pacific were analyzed to examine the influence of oceanic and climatic conditions in spawning grounds on catches of Japanese common squid, Todarodes pacificus, in the East (Japan) Sea. The main spawning ground was divided into four sub-areas: the South Sea of Korea (R1), the southern waters off Jeju, Korea (R2), the southwestern part of Kyushu, Japan (R3), and the northern part of Okinawa, Japan (R4). Interannual and decadal fluctuations in water temperatures correlated well with squid catches in the East/Japan Sea. In particular, water temperatures at a depth of 50 to 100 m in sub-areas R3 and R4 showed higher correlation coefficients (0.54 to 0.59, p<0.01) in relation to squid catches in the East/Japan Sea than for R1 and R2, which had correlation coefficients of 0.40 or less (p>0.05). Air temperature and wind velocity fluctuations in each sub-area are correlated with water temperature fluctuations and were closely connected with variations in the surface mixed layers. Water, air temperatures and wind velocities at the main spawning grounds are linked to the Southern Oscillation Index (SOI) with higher signals in the ca. 2-4-year band. Strong changes in a specific band and phase occurred around 1976/77 and 1986/87, coincident with changes in squid catches.

• 자원환경지질
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• 제29권4호
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• pp.429-437
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• 1996

The purpose of this study is to correct the nodule abundance of FFG (Free Fall Grab) sampler on KODOS (Korea Deep Ocean Study) area in North-East Pacific Ocean. The image analysis of sea-floor photography was carried out for correcting the abundance of nodules, and the image enhancement techniques and edge detection method were used to discriminate between nodules and sediments. The trace of nodules on sediments was detected to reduce the fractionation effect in calculating the coverage of nodules. The three methods, using the coverage of nodules, using the volume density, and using corrected volume density, were utilized for the correction of the nodule abundance. The method using the coverage of nodules was more convenient and available for the correction of nodule abundance than the other two methods. The method using the corrected volume density had the highest confidence level compared with the other methods.

• 한국대기환경학회지
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• 제12권3호
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• pp.297-305
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• 1996

Aerosol measurements were carried out at Kosan, Cheju Island, Korea for the period from July 20 to August 10, 1994. Total suspended particles were collected by high volume samplers and PM 2.5 particles with gaseous volatile species were collected by a filter pack sampler and their ionic composition are analyzed. The average mass concentration of PM 2.5 particles was comparable to that of PM 3 particles collected during March, 1994 at the same site but the average non sea-salt sulfate concentration was higher that that of PM 3 particles, implying the fraction of anthropogenic air apllutants during this period is higher than that during March, 1994. During the measurement period, two distincitive patterns were observed, high concentrations of mass and water soluble ions were observed between July 20 and August 1 while those during after August 2 were low. Back trajectory analysis results show that air masses arriving at Kosan during the earlier period were mainly from Korea and Japan while those during the later period were from the North Pacific Ocean. It is suggested that the particle ion concentrations during the later period are marine background concentrations at Kosan during the summertime.

• 대기
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• 제16권1호
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• pp.1-17
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• 2006

The purpose of this study is to find out the change of statistical characteristics of typhoons affecting the Korean Peninsula. For this purpose, we analyzed the occurrence frequency of typhoon for 50 years (1954-2003) and change of air temperature and sea surface temperature near the Korean Peninsula in the same period. We classified typhoon tracks affecting the Korean Peninsula, and analyzed their trends and the amount of damage by typhoon. While the annual occurrence frequency of typhoon in the western North Pacific gradually decreased, its frequency affecting the Korean Peninsula increased. In addition, the occurrence location migrated northward. This coincides with the increase in air temperature and sea surface temperature around the Korean Peninsula. Typhoon tracks affecting the Korean Peninsula were classified into 7 types. Among them, the occurrence frequency of type 6 and 7 has increased. Although the occurrence frequency is low in type 2, the amount of damage by typhoon and occurrence frequency are increasing recently.

• 대기
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• 제22권4호
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• pp.449-454
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• 2012

This study presents the long-term variability of spring precipitation over the Korean peninsula. It is found that the significant interdecadal change in the spring precipitation has occurred around year 1991. Over the Korean peninsula the precipitation for the post-1991 period increased by about 30 mm per year in CMAP and station-measured data compared to the precipitation prior to year 1991. Due to an increased baroclinicity during the later period, the low-level negative pressure anomaly has developed with its center over northern Japan. Korea is situated at the western end of the negative pressure anomaly, receiving moisture from westerly winds and producing more precipitation. Also, we estimate the change in the near future (years 2020~2040) spring precipitation using six best performing Coupled Model Intercomparison Project 3 (CMIP3) models. These best model ensemble mean shows that spring precipitation is anticipated to increase by about 4% due to the strengthened westerlies accompanied by the northwestern enhancement of the North Pacific subtropical high.

• 대기
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• 제24권2호
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• pp.189-196
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• 2014

The definition of onset date of Changma is revisited in this study using a quality controlled Ieodo ocean research station data. The Ieodo station has great importance in terms of its southwest location from Korean Peninsula and, hence, makes it possible to predict Changma period in advance with less impact of continents. The onset date of Changma using the Ieodo station data is defined by the time that meridional wind direction changes and maintains from northerly to southerly, and then the zonal wind changes from easterly to westerly after first June. This definition comes from a recognition that the establishment and movement of the western North Pacific subtropical high (WNPSH) cause Changma through southwesterly flow. The onset data of Changma has been determined by large-scale dynamic-thermodynamic characteristics or various meteorological station data. However, even the definition based on circulation data at the Ieodo station has a potential for the improved prediction skill of the onset date of Changma. The differences between before and after Changma, defined as Ieodo station data, are also found in synoptic chart. The convective instability and conspicuous circulations, corresponding low-level southwesterly flow related to WNPSH and strong upper-level zonal wind, are represented during Changma.

• 한국지구과학회지
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• 제28권5호
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• pp.545-555
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• 2007

Ocean general circulation model developed by GFDL on the basis of MOM4 of FMS are examined and evaluated in order to elucidate the global ocean status. The model employs a tripolar grid system to resolve the Arctic Ocean without polar filtering. The meridional resolution gradually increases from $1/3^{\circ}$ at the equator to $1^{\circ}$ at $30^{\circ}N(S)$. Other horizontal grids have the constant $1^{\circ}$ and vertical grids with 50 levels. The ocean is also coupled to the GFDL sea ice model. It considers tidal effects along with fresh water and chlorophyll concentration. This model is integrated for a 100 year duration with 96 cpu forced by German OMIP and CORE dataset. Levitus, WOA01 climatology, serial CTD observations, WOCE and Argo data are all used for model validation. General features of the world ocean circulation are well simulated except for the western boundary and coastal region where strong advection or fresh water flux are dominant. However, we can find that information concerning chlorophyll and sea ice, newly applied to MOM4 as surface boundary condition, can be used to reduce a model bias near the equatorial and North Pacific ocean.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.300-303
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• 2001

The first 7 years of altimeter data from the TOPEX/POSEIDON (T/P) were analyzed to study the surface circulation and its variability in the East Asian Marginal Seas. Long term averaged T/P sea level time series data where compared with in situ sea level measurements from a float-operated type tide gauge around of south Korea and Japan. T/P data are a large contaminated by 60-day tidal aliasing effect, very near the alias periods of M2 and S2. When this 60-day effect is removed, the data agree well with the tide gauge data with 4.6 cm averaged RMS difference. The T/P derived sea level variability reveals clearly the well-known, strong current-topography such as Kuroshio. The T/P mean sea level of North Pacific (NP) was higher than Yellow Sea (YS) and East Sea (ES). The T/P sea level valibility, with strong eddy and meandaring, was the largest in eastern part of Japan and this variability was mainly due to the influence of bottom topography in Kuroshio Extention area.

• Journal of Plant Biology
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• 제3권2호
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• pp.19-25
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• 1960

1. This study was made on the flora of bryophytes on Mt. Kwanak, which is situated ($37^{\circ}$30' N. Lat. $127^{\circ}$O'E. Long) to the south of Seoul area. 2. The bryophytic flora of this mountain consists of the following elements. 1) Holarctic elem, Musci………16 species (25.0%), Hepaticae………4 species (28.6%). 2) North Pacific elem. M.………1 species (1.56%), H………O. 3) Cosmopolitan elem. M………10 species (15.65%), H………1 species (7.1%). 4) East-Asiatic elem. M………16 species (25%), H.………4 species (28.6%). 5) Tropical elem. M.………3 species (4.68%), H.………3 species (21.4%). 6) Japane-Korean elem. M.………17 species (26.56%), H.………2 species (14.3%). 7) Endemic elem. M.………1 species (1.56%), H.………O. 3. In the list of bryophytes of Mt. Kwanak, 62 species, 1 variety and 1 subspecies belonging to 47 genera for Musci and 12 species 2 subspecies belonging to 10 genera for Hepaticae were enumerated. Of these the following 5 species are new to Korean flora. 1) Macromitrium japonicum D.M. 2) Entodon arenosus Okam. 3) E. okamurae Broth. 4) Gollania ruginosa (Mitt.) Broth. 5) Temnona birmensis (St.) Hatt.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.167-173
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• 2002

For moving cargo between the North Pacific region and Northern European ports, the Northern Sea Route, along Russia's coastline, is 35-60% shorter than the traditionally used routes through the Suez and Panama Canals. In addition to its shorter distance, there exists and extensive ports and shipping infrastructure, and the potential for developing new markets in Russia and other northern countries including Korea and Japan. These incentives attracted considerable attention from the international shipping and shipbuilding industries and have formed a cooperative international research program, called as the International Northern Sea Route Programme (INSROP). This paper is a general compilation of the historical usage, recent trade developments, the physical environment, and the practical considerations that may shape future operational mode of shipping in the NSR based on results from INSROP reports. This study focuses mainly on an operation of commercial icebreaking vessels that may be utilized along the NSR.