• Atmosphere
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• v.20 no.3
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• pp.239-246
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• 2010

In this study, the climatological characteristics of the landfall typhoons on North Korea are surveyed to estimate the frequency, the intensity, the track, and their damage. The data for the period of 1951-2008 are used from both RSMC (Regional Specialized Meteorological Center) Tokyo Typhoon Center and NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research), EM-DAT (Emergency Events Database). There are the ten highest frequencies from 1961 to 1965 and is one frequency for the period of both 1966-1979 and 1976-1980 respectively. Even if a clear trend on the frequency of typhoon is not defined, it is noticeable the intensity has been weak since the frequency of TS (Tropical Storm) decreased. In order to figure out both the characteristic of intensity and the relation between the typhoon track and the expansion of North Pacific High (NPH), Typhoon's tracks are classified into three types as follows: (I) landing on the west coast of North Korea through the mainland of China, (II) landing on the west coast of North Korea, (III) landing on a central/eastern part of the Korean peninsula through South Korea. More often than not, the characteristic of Type (I) is the case of a landfall after it becomes extratropical cyclone. Type(II) and Type(III) show a landfall as TS grade, by comparision. On the relation between the typhoon's track and the expansion of NPH analyzed, Type (I) shows the westward expansion while both Type (II) and Type (III) show the northward expansion and development of NPH. This means the intensity of a typhoon landfall on North Korea is variable depending on the development of NPH. Finally, only two cases are found among total five cases in EM-DAT, reportedly that North Korea was damaged. And therefore, the damage by the wind of Prapiroon (the $12^{th}$ typhoon, 2000) and heavy rainfall with Rusa (the $15^{th}$ typhoon, 2002) landing on North Korea was analyzed. Moreover, it is estimated both Prapiroon and Rusa have done badly damaged to North Korea as the economical losses of as much as six billion and five hundred-thousand US dollar, respectively.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.457-469
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• 2006

This study aims to understand the characteristics of spatial distribution of snowfall and to analyze its development mechanism in Honam province in Korea. The areas of snowfall in Honan area can be divided into the seven sub-area by snowfall pattern. In the west coastal area of heavy snowfall and the southwest coastal area of heavy snowfall, snowfall develops over reason of ocean by Siberian High while in the northern inland area of heavy snowfall and the southern inland area of heavy snowfall, it develops when a strong Siberian High affects to inland. Then, much snowfall is by a forced ascending due to topography in Namwon, Imsil and Gwangju of the northwestward of the Noryung and Sobaek mountain ranges while it is weak in Jeonju and Suncheon of the low plains and the southeastward. In the mountainous area of heavy snowfall and the south coastal area of light snowfall, cyclone is also one of causes of snowfall. In the southwest coastal area, snowfall is meager than the southwest coastal area of heavy snowfall because this area is far from the west coast. It is confirmed that the snowfall difference of the coast, inland and mountainous area appears by temperature difference of sea surface and 850hPa temperature, wind speed of Siberian High.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.298-307
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• 2023

The annual reproductive cycle of two species, Upogebia major (de Haan 1841) and Austinogebia wuhsienweni (Yu 1931), of the female mud shrimp from the west coast of Korea was investigated using histology. The collected samples were divided into adult and juvenile groups to understand the mature period of age class based on the carapace length(CL). Juvenile Upogebia(CL<25mm) were mostly inactive gonad with early (62%-100%) and late (10%-38%) development stages during the year, whereas the adult shrimp showed a seasonal pattern of gonad maturation(CL≥25 mm). The early and late developmental stages of oocytes were observed in adult Upogebia from November to March and mature eggs appeared from April to October. In adult Ausitnogebia (CL≥15 mm), fully grown oocytes were consistently observed during the study period, in which the ripe stage was found between January and June. On the other hand, most juvenile Austinogebia (CL<15 mm) maintained an immature state in the gonad. Both species of the mud shrimp reproduced from ovigerous females in the adult population and their egg-bearing period was distinguished from January to April for U. major and from July to September for A. wuhsienweni.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.409-425
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• 2019

Marine terraces, a step-like landform, are important geologic markers that provide tectonic information during the Quaternary Period. Marine terraces are well developed along all coastlines(East, West, and South) of the Korean Peninsula, those along the East coastline are the most distinctive. The marine terraces of the East coastline are classified into 4-6 flights that are several meters or several tens of meters above the present sea level. It is believed that these terraces, except for the lowest one, were formed in the middle Pleistocene. In the base of the OSL age dating results and Blake excursion events of magnetostratigraphy, the $2^{nd}$ and $3^{rd}$ terraces are correlated to the last interglacial stage. Considering the marine terraces linked to a sea-level curve of the Pleistocene, it is thought that regional tectonic movements have uplifted the East coastal area since the middle Pleistocene. Besides, former shorelines of each terrace have varied elevations from Gangreung to Busan bay, which can be divided into four regions, namely, Gangreung-Yonghanri(I), Homikot-Najung(II), Najung-Bangeojin(III), and Waesung-Busan Bay(IV). The former shorelines of each terrace at both Gangreung-Yonghanri(I) and Najung-Bangeojin(III) are higher than those in the other two regions, due to block movements by regional faults such as the Ocheon Fault or its subsidiaries, the Gampo Lineament and Ulsan Fault. Uplift rate of the East coast ranges from 0.2 m/ky to 0.3 m/ky, but each region shows different uplift rate.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.113-125
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• 2011

In this study, recent trends of the annual precipitation, the annual maximum precipitation of different durations and the rain days over several thresholds(i.e. 0, 10, 20, 40, 60 and 80 mm/day) according to the different local features were analyzed using daily precipitation data of 59 weather stations between 1973 and 2009. To analyze the variability according to the regional characteristics, 59 weather stations were classified by elevations, latitudes, longitudes, river basins, inland or shore(east sea, south sea, west sea) area and the level of urbanization. Results demonstrated that overall trend of variables increases except rain day. Results according to the regional characteristics showed that the increase trend becomes stronger with elevation increase. The increase trend of Han river basin is largest and that of Youngsan river basin is smallest. Also the increase trend becomes stronger with latitude increase and that of East coast is larger than that of South coast since it may be caused by the regional difference of elevation. The increase trend of urban area is larger than that of rural area. Overall trend showed that increase trend becomes stronger with elevation and latitude increase.

• Journal of the Korean earth science society
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• v.21 no.2
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• pp.128-136
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• 2000

To understand the variation and transport pattern of suspended matters, salinity, tidal current and suspended matters in semiclosed Muan Bay have been monitored during winter and summer. The suspended matters show considerably seasonal variations with low concentration and homogeneity in the water column during winter season, but with high concentration and layering during summer season. Particularly, during summer season, the freshwater and the suspended matters influxed by the gate operation of the Youngsan River sea-dike are transported northward in accordance with the would flow into the inner-bay by relaxed flood currents after the construction of sea-dike and sea-walls in the Mokpo coastal zone. But, in the south bay-mouth, those matters outflow through the bay-mouth, resulting from tidal ebb dominance and asymmetry in the west bay-mouth. The residual suspended matter flux is much higher in the south bay-mouth(-0.0955kg/m ${\cdot}$ sec) than that of west bay-mouth(0.0078kg1m ${\cdot}$ sec). Accordingly, The Muan Bay is interpreted as erosion-dominated environments, and the erosion somewhat progresses in the intertidal flat of the bay.

• Economic and Environmental Geology
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• v.4 no.1
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• pp.11-18
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• 1971

The geotectonics and geomorphic structure of Korea resulted from the Song-rim Disturbance and the Daebo orogenic movements. Afterward this mountainous peninsula underwent several geological changes on a small scale, and it was also claimed that the steady rising of the elevated peneplain of the eastern coast and the submerging of the southwestern coastal area are largely due to the tilted block movement. These views have been generally accepted good in several ways, but they are limited in range or lacking in theoretical integration. The present writer investigated the geology of the Mt. Chi-ri-san and the Honam coal mining area for a geological map in 1965, respectively. The results of these studies convinced the present writer that the conventional views, which were based upon a theory of lateral pressure should be reconsidered in many respects, and more recent studies made it clear that the morphological development in the southwestern area can be better explained by the orogenic movement and rock control. The measurement of submerging speed of the western coastal area (Pak. Y. A., 1969) and a new account on the geology and tectonics of the Mid-central region of South Korea (Kim O.J., 1970) act as an encouragement to a new explanation. The present writer's researches on the extreme southwestern portion of the peninsula show that the steady submerging of this area cannot be attributed to a simple downthrown block phenomenon caused by block movement. It is no more than the result of the differential movement of uplifting in the eastern and western coastal areas and the rising of sea-level in the post-glacial period. This phenomenon could be easily explained by the comparison of the rate of rise in sea-level and amount of heat flow between Korea and other areas in the world. The existance of the erosional planes in the Sobaik-San ranges also provide an evidence of an upheaval in the western coast area. Though the Sobaik-San ranges largely follow the direction of the Sinian system. They consist of the numerous branches, whose trends run more or less differently from their main trend because of the disharmonic folding, are converged into Mt. Sobaik-San and Chupungryung. The undulation of the land is not wholely caused by orogenic movements, where as the present writer confirmed that the diversity of morphological development is the direct reflection of geological conditions such as rocks and processes which constitute the basic elements of geomorphic structure. An east-west directed mountain range which could be named as Hansan mountain range, was claimed to be oriented by the joint control. The geological conditions such as a special erosion and weathering of agglomerate and breccia tuff usually produce pot-hole like submarine features which cause the whirling phenomenon at the southwestern coast channel.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.129-135
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• 2006

This study was performed to characterize the seasonal variation of water quality and sediment environment from May, 2004 to February, 2006 in 21 stations of Gwangyang bay. Gawngyang bay is located in the middle of south coast of Korea and semi-dosed with Yeosu peninsula, Gwangyang-city and Namhea-do. Water quality at the west coast of Myo-do were highly deteriorated than other stations. At summer season(July 2005), the concentration of the most analytical items were highly detected than other seasons and the lowest concentration was at the winter season(January 2005, February 2006). Especially, DIP and TP were highly detected around the coast of Yeosu industrial complex. N/P ratio were higher than 16 of Redfield ratio in the spring(May 2005) and winter(February 2006) at the surface layer. While at other seasons and most stations were lower than 16 of Redfield ratio. In the survey of sediment environment, ignition loss(IL), chemical oxygen demand(COD) and acid volatile sulfide(AVS) were in the range of $2.51\sim22.10%,\;2.65\sim48.41mg/g-dry\;and\;0.01\sim8.95mg/g-dry$, respectively. COD in surface sediment was highest at summer season AVS was highest at autumn. In sediment, the corelationship coefficients between COD and IL, COD and AVS were 0.65 and 0.44, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.205-211
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• 2016

Based on the Expendable Bathythermograph (XBT) observation and serial oceanographic observation of National Institute of Fisheries Science (NIFS) during July 2013 to July 2015, we examined the temperature variation in the Ulleung Warm Eddy (UWE) in the East Sea. The UWE was always shown during the observation periods even though it was not the whole shape. The coefficient of variation (CV) was largest in the depth of 250 m at the side of the east coast of Korean Peninsula with $3{\sim}4^{\circ}C$ in temperature. CV of the horizontal distribution at 250 m depth was also largest in the region biased along the east coast of Korea. The warm eddy moved not only to the east-west direction but also to the north-south direction in the viewpoint of horizontal distributions of temperature. This region between the Korean Peninsula and Ulleung island also is the passage of the East Korean Warm Current. This means that interaction between the East Korean Warm Current and periphery of warm eddy makes large in the variation of movement along the east coast of Korean Peninsula. The largest variation of temperature at 250 m depth seemed to be significantly correlated with the East Sea Intermediate Water (ESIW) underlying Ulleung Warm Eddy. It is suggested that the interaction between the ESIW and UWE is active in the mid-depth along the periphery of UWE.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.535-547
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• 2021

Aggregate is an essential construction material, and the demand is increasing every year. Aggregate has different properties in each region, and it is difficult to supply it over long distances due to its quantity and weight. For the stabilization of aggregate supply and demand, regional aggregate resource surveys have been conducted since 1993 in Korea. In this study, an aggregate resource survey was conducted in Goyang City to understand the characteristics of aggregate distribution as part of the annual regional aggregate resource survey in 2020. Goyang City has a high mountainous area to the east, and the southwestern part shows a topography where a wide flatland develops. It has 18 small streams originated from the eastern mountainuos area and 1 large stream Han River. The drilling data shows that thickness of the Quaternary deposits tend to deepen toward the south. The aggregate reserves are relatively abundant, the depth of the aggregates are relatively deep. Changes in the depth of the Quaternary deposits and the amount of aggregate in Goyang are seems to be closely related to the activities of the Han River rather than the sedimentation characteristics from the upstream to the downstream of the small streams. This characteristics show a similar tendency to the distribution of aggregates in adjacent regions to the west coast in Korea. Therefore, the regions that close to west coast have a high probability of aggregate reserves around relatively large-scale streams flowing into the west coast.