• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.4
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• pp.347-353
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• 2017

In this study, numerical experiments were conducted to identify distribution of rising flow and flux in the East Sea of Korea, where the coastal upwelling occurs. Temperature and salinity data from CTD observations and NIFS during summer 2013 were applied to the model. Numerical experiments were carried out with different wind speed (3, 6 m/s and 9 m/s) and direction (southerly and southwesterly), which represent the most frequent in summer conditions. As a result of calculation, upwelling flow rate was found to be highest in Pohang between five coasts(Hupo, Youngduk, Pohang, Ulsan and Busan). Comparing with southerly wind conditions, the rising flow rate is about 1.5 times greater when southwesterly wind was applied. Horizontal diffusion of the upwelling area is expected to have a speed of 17~22 km/day when a 9 m/s southwesterly wind is applied. If this wind continues over one week, a cold pool will be generated by upwelling that may reach to the Ulleung area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.186-194
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• 2020

In this study, spectral analysis was conducted to identify environmental factors af ecting short-term changes in water temperature in the East, West and South coasts of Korea. The data used in the spectrum analysis is the 2016 summer water temperature, air temperature, tide level and wind data provided by Korea Hydrographic & Oceanographic Agency. In power spectrum results, peaks of water temperature and tide level were observed at same periods in West Sea (Incheon, Pyeungteak, Gunsan and Mokpo) and South Sea (Wando, Goheung, Yeosu, Tongyeong and Masan) where mean tidal range was more than 100 cm. On the other hand, periodicity of water temperature did not appear in East Sea and Busan where the mean tidal range was small. Coherence analysis showed that water temperature was highly correlated with tide in West Sea and three stations(Wando, Goheung and Tongyeong) of South Sea. Especially, correlation between water temperature and tide level in Wando and Tongyeong presented 0.96 at semi-diurnal period. Water temperature in Yeosu seems to have influenced by tide and inflow of fresh water. In Masan, water temperature is influenced by south wind, tide and inflow of fresh water. In East Sea, influence of tide on water temperature is small due to current and small tidal range. As a result of comparing the time series graph, stations where the correlation between water temperature and tide is high show that relatively cold water was inputted at flood tide and flow out at ebb tide. short-term variation of water temperature was affected by tide, but long-term variation over a month was affected by air temperature.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.564-573
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• 2014

The objective of this study was to select a representative coastal disaster prevention forest type for each coastal area. In this study, we used cluster analysis with the results obtained from investigation for density of growing stock, tree height, DBH, and forest width and length of major coastal disaster prevention forests distributed in the west, the south, and the east coasts. The results showed that the coastal disaster prevention forests for each coast were classified into two types: a forest type with small DBH and high growing stock density (W1) or with high tree height (W2) in the west coast, a forest type with small tree height (S1) or with large DBH (S2) in the south coast, and a forest type with small growing stock density (E1) or with small tree height and low DBH (E2) in the east coast. The coastal disaster prevention forests located in Gurye beach (Hwangchon-ri, Wonbuk-myeon, Taean-gun, Chungcheongnam-do) and in Gohsapo beach (Unsna-ri, Byeonsan-myeon, Buan-gun, Jeollabuk-do) were selected as the representative forests of W1 and W2, respectively. In addition, the coastal disaster prevention forests located in Namyang beach (Namyang-ri, Seolcheon-myeon, Namhae-gun, Gyeongsangnam-do) and in Donggo beach (Donggo-ri, Sinji-myeon, Wando-gun, Jeollanam-do) were selected as the representative forests of S1 and S2, respectively. Last, the coastal disaster prevention forests located in Bonggil beach (Bonggil-ri, Yangbuk-myeon, Gyeongju-si, Gyeongsangbuk-do) and in Anmeok beach (Gyeonso-dong, Gangneung-si, Gangwon-do) were selected as the representative forests of E1 and E2, respectively. Our finding is expected to be used as baseline data in establishing the most appropriate coastal disaster prevention forest for each coast.

• Journal of the Korean Geographical Society
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• v.49 no.3
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• pp.321-338
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• 2014

This study aims to identify spatial distribution of estuarine wetlands in Korea, and to assess temporal variation of the wetlands in the last few decades. Widely known in environmental and coastal management, watershed-based regions which composed with Han-river(western and eastern parts), Keum-river, Yeoungsan-river, Seomjin-river, Nakdong-river, and Jeju, are analyzed to evaluate temporal change of estuarine wetlands in the 1980s, 1990s, and 2000s, through the land-cover map. Results show that estuarine wetlands dramatically decreased in Han-river(western part), Keum-river, Yeoungsan-river that estuarine circulation have been interrupted with man-made structures such as dyke and drainage. But, estuarine wetlands surrounded by forests and grasslands has been relatively less damaged. Habitat diversity providing healthy estuary ecosystem is lower in interrupted estuaries than circulated estuaries, which are composed of tidal-flat, open water, salt marsh, rocky coasts and sandy shoreline. This study indicates that spatial distribution and temporal variation of estuarine wetlands are different with estuary type and region, so estuary type with seven regions can be applied to provides a framework for estuary management strategies and to establish estuary restoration plans.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.316-316
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• 2017

The objective of this study is to estimate quantitatively soil salinity and soil loss at upland soils in agriculture land region in Saemangeum reclaimed land on the south Korea coasts. Soil loss and soil salinity are the most critical problem at reclaimed tidal saline soil in Korea. The several thematic maps of research area such as land cover map, topographic and soil maps, together with tabular precipitation data used for soil erosion and soil salinity calculation. Meteorological data were measured directly as air temperature, wind speed, solar radiation, and precipitation. The experiment was conducted 2% sloped lysimeter ($5.0m{\times}20.0m$) with 14 treatments and it were separated by low salinity division (LSD) and high salinity division (HSD) install. The cation content in ground water increased during time course, but in the case of land surface water the content was variable, and $K^+$ was lower than that of $Na^+$ and $Mg^{2+}$. At the LSD under rainproof condition, the salinity was directly proportional to soil water content, but at the HSD the tendency was no reversed. In condition of rainproof, the amount of soil salinity was higher at the HSD than at the LSD. Positive correlation was obtained between the soil water content and available phosphorous content at the rainfall division, but there was no significance at the surface soil of the rainproof division. Sodium adsorption ratio and anion contents in soil were repressed in the order of vinyl-mulching > non-mulching > bare field. According to the result of analyzing soil loss, soil loss occurred in a vinyl-mulching, a non-mulching and a bare field in size order, and also approximately 11.2 ton/ha soil loss happened on the reclaimed land area. The average soil loss amount by the unit area takes place in a non-mulching and bare field a lot. Our results indicate that soluble salt control and soil erosion are critical at reclaimed tidal saline soil and the results can provide some useful information for deciding management plans to reduce soil loss and salt damage for stable crop production and diverse utilization or cultivation could be one of the management options to alleviate salt damage at reclaimed tidal saline soil in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.9-16
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• 2004

Parapenaeopsis tenella occurs widely on the south and west coasts of Korea. Sex ratio showed seasonal variations, with a mean value of 48.6% for the females. The species produces one cohort a year, with the ovaries ripening from July to August. Insemination took place from July to August, as more than half of the females sampled in the study over 14 mm CL were inseminated. Gonadosomatic index (GSI) reached the maximum between July and August. The smallest mature female was 11 mm CL. Size at 50% sexual maturity ($CL_{50}$), determined from both mature females and inseminated females, was 12.53 mm and 12.28 mm CL, respectively. The life span of females appeared to be 14-15 months according to size frequency distributions, while that of the male was 13-14 months. Population growth was estimated by the modified von Bertalanffy growth function incorporating seasonal variation in growth. Based on the growth parameters (K = 1.22 $yr^{-1}$ and $L_{\infty}$ = 21.99 mm CL for females, and K = 2.00 $yr^{-1}$ and $L_{\infty}$ = 15.00 mm CL for males) growth curves showed that females grew faster and reached a larger size at age than males.

• Journal of Korean Society of Forest Science
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• v.89 no.1
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• pp.93-104
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• 2000

The ecological characteristics of 10 natural stands of Dendropanax morbifera(Haenam, Wando 1, Wando 2, Bogildo, Kemundo and Hongdo and Sendol, Suoak, Hannam, and Kidowon populations in Cheju island) were studied. In most of the Dendropanax morbifera natural stands, the following tree species appeared predominantly : Camellia japonica, Castanopsis cuspidate var. sieboldii, Castanopsis cuspidate var. thunbergii, Carpinus laxiflora, Quercus acute and Eurya japonica. Especially, Camellia japonica and Eurya japonica appeared in all the stands. Dendropanax morbifera occupied 17.2% of the upper story, 12.9% of the middle story, and 10.3% of the lower story, respectively. The distribution patterns by Morisita's Index showed that Dendropanax morbifera was distributed randomly in all of the three stories, i.e. the upper, the middle and the lower stories. Dendropanax morbifera was positively associated with Camellia japonica, Eurya japonica, Carpinus laxiflora, Cinnamomum japonicum, Ligustrum japonicum, Callicarpa Japonica, Castanopsis cuspidate var. thunbergii, Castanopsis cuspidata var. sieboldii, Daphniphyllum macropodum, Acer palmatum and Euonymus oxyphyllus. This might suggest that the ecological niche is similar to each other. The cluster analysis using percent dissimilarity(PD) based on species composition divided into two groups. One group consisted of the populations located along the south-western coasts. The other group consisted of the populations of Cheju island. This result was agree with that of ordination analysis. From these results, We could find out that the species composition of the populations of Dendrapanax morbifera in Cheju island was quite different from those of other regions.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.5
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• pp.312-317
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• 2016

The submersion and emersion patterns are key factors that directly influence the habitat environment of the coastal plants and animals. In this study, the coasts are divided into five zones (zones 1, 2, 3, 4, and 5 - not flooded, flooded once, flooded and exposed to air twice, exposed to air once, continuously flooded in the day, respectively) based on the patterns using tidal elevation data at the major eight stations and the domestic and international reference tidal levels, i.e., AHHW, ALLW, HAT and LAT, are also estimated to analyse the characteristics of the five distinct zones. Based on the results, the frequency of the zone 3 are dominant and forms from 87.2% to 88.2% (nearly constant) irrelevant with the tidal ranges at all stations. The taking-up percentages of the zones 2 and 4 show nearly constant, below 4% and over 8%, respectively. In Pohang station classified as the mainly diurnal tide, the percentages are decreased to 1.4% in zone 2 and increased to 10.8% due to the effects of the annual and semi-annual tidal components.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.2
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• pp.120-127
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• 2003

In Korea, Trachysalambria curvirostris occurs widely along the south and west coasts with a range extending from Kanghwado in the northwest down to Sarangdo in the southeast. Sex ratio showed seasonal variations, with a mean value of 48.6% for the females. T. curvirostris produces one cohort a year, with the ovaries ripening from July to August. Insemination appeared to take place from June to August, as more than half of the females sampled in the study of over 19 mm carapace length were inseminated. The mean gonado somatic index (GSI) reached a maximum between July and August. The smallest mature female found was a 18 mm carapace length (CL). Size at 50% sexual maturity (CL$_(50)$), determined from both mature females and inseminated females was 18.89 mm and 19.91 mm CL, respectively. The life span of females appeared to be 14-15 months according to size frequency distributions, while that of the male was 13-14 months. Population growth was estimated by the modified von Bertalanffy growth function incorporating seasonal variation in growth. Based on the growth parameters (K = 1.40 yr$_(-1)$ and L$L\infty$ = 29.54 mm CL for females, and K = 2.00yr$_(-1)$ and L$L\infty$ = 18.95 mm CL for males) growth curves showed that females grew faster and reached a larger size than males.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.4
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• pp.273-283
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• 2020

Numerical simulations of the storm surge and waves induced by the Typhoon Bolaven incident on the west sea of Korea in 2012 are performed using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the various coasts of Korea. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the Korea Hydrographic and Oceanographic Agency and the Korea Meteorological Administration. Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the Joint Typhoon Warning Center, and the calculated results are compared and analyzed. The waves and storm surges calculated using JMA-MSM wether field agree well with the observations because of the better reflection of the topography and the pre-background weather field. On the other hand, the calculated results based on the weather fields produced using the JTWC best track information show some limitations of the general trend of the variations of wave and surge heights. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.