• Title/Summary/Keyword: South-East Region

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Primary production by phytoplankton in the territorial seas of the Republic of Korea

  • An Suk, Lim;Hae Jin, Jeong
    • ALGAE
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    • v.37 no.4
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    • pp.265-279
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    • 2022
  • The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km2) was estimated at 11,227 Gg C y-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.

Islamization or Arabization? The Arab Cultural Influence on the South Sulawesi Muslim Community since the Islamization in the 17th Century

  • Halim, Wahyuddin
    • SUVANNABHUMI
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    • v.10 no.1
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    • pp.35-61
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    • 2018
  • This paper explores the influence of Arab culture on the culture of Bugis-Makassar, the two major ethnic groups in South Sulawesi, Indonesia, particularly after their Islamization in the early 17th century. The paper argues that since then, the on-going process of Islamization in the region has also brought a continuous flow of ideas and cultural practices from Mecca to Indonesia by means of the hajj pilgrims, Arab traders, and the establishment of Islamic educational institutions that emphasized the teaching and use of Arabic language in education. These factors, among others, have facilitated a cultural inflow which enabled cultural practices borne of West Asia (Middle East) to be integrated into local customs and beliefs. The paper particularly depicts the most observable forms of Arabic cultural integration, acculturation, and assimilation into the Bugis-Makassar culture such as the use of Arabic in Islamic schools and religious sermons; the Arab-style dressing by religious scholars, teachers, and students; the wearing of the hijab (head cover) by women; and the change of people's names from local into Arabic. By utilizing the historical and anthropological approach, this paper investigates this dynamic process of adaptation and integration of a foreign culture that first came through the Islamization of a local culture, exploring the role of an Islamic missionary and educational institutions in mediating and maintaining such cultural integration processes.

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Computational Procedure for Sea Subface Topography of East Asian Marginal Seas using Geosat Altimeter Data (Geosat 고도계자료를 이용한 동아시아해역의 해면변위 산정법)

  • 최병호;고진석
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.12 no.1
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    • pp.107-118
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    • 1994
  • As satellite altimetry is being progressed to apply with heigher precision to maginal seas, it was necessary to improve correction procedures for tidal signals in altimetry with more accurate tidal model than well-known model of Schwiderski for studying marginal sea dynamics. As a first step, tidal regime of semidiurnal tides$(M_2,\;S_2,\;N_2,\;K_2)$ and diurnal tides$(K_1,\;O_1,\;P_1,\;Q_1)$ were computed with a finer details of formulation of tidal model over the East Asian Marginal Seas covering the Okhotsk Sea and South China Sea and part of Northwest Pacific Ocean with mesh resolutions of 1/6$^{\circ}$. Subsequently the computed sets of harmonic constants from the model were used to remove the tide in selected Sea Surface Heights from Geosat in the modelled region. Preliminary correction procedure suggested in the present study may be extensively used for obtaining Sea Surface Topography over the East Asian Marginal Seas, especially for the region where Schwiderski's harmonic constants are not available.

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A Study on Sensitivity of Heavy Precipitation to Domain Size with a Regional Numerical Weather Prediction Model (지역예측모델 영역 크기에 따른 집중호우 수치모의 민감도 실험)

  • Min, Jae-Sik;Roh, Joon-Woo;Jee, Joon-Bum;Kim, Sangil
    • Atmosphere
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    • v.26 no.1
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    • pp.85-95
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    • 2016
  • In this study, we investigated the variabilities of wind speed of 850 hPa and precipitable water over the East Asia region using the NCEP Final Analysis data from December 2001 to November 2011. A large variance of wind speed was observed in northern and eastern China during the winter period. During summer, the regions of the East China Sea, the South Sea of Japan and the East Sea show large variances in the wind speed caused by an extended North Pacific High and typhoon activities. The large variances in the wind speed in the regions are shown to be correlated with the inter-annual variability of precipitable water over the inland region of windward side of the Korean Peninsula. Based on the investigation, sensitivity tests to the domain size were performed using the WRF model version 3.6 for heavy precipitation events over the Korean Peninsula for 26 and 27 July 2011. Numerical experiments of different domain sizes were set up with 5 km horizontal and 50 levels vertical resolutions for the control and the first experimental run, and 9 km horizontal for the second experimental run. We found that the major rainfalls correspond to shortwave troughs with baroclinic structure over Northeast China and extended North Pacific High. The correlation analysis between the observation and experiments for 1-h precipitation indicated that the second experiment with the largest domain had the best performance with the correlation coefficient of 0.79 due to the synoptic-scale systems such as short-wave troughs and North Pacific High.

Re-emergence of the Glossy Ibis (Plegadis falcinellus) in inland South Korea

  • Lee, Sang-Yeon;Sung, Ha-Cheol;Han, Donguk;Cha, Jin-Yeol
    • Journal of Ecology and Environment
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    • v.44 no.3
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    • pp.155-161
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    • 2020
  • Glossy Ibis (Plegadis falcinellus), which has never been recorded in South Korea, appeared on Jeju Island in 2018 and re-emerged in the inland area of Seocheon-gun (South Chungcheong Province) and in Goyang-si (Gyeonggi Province) in the following year. This study aims to report the progress in observing P. falcinellus in the inland areas of South Korea in 2019 and to predict its origin region and future propensity for habitats in the country through literature review. On 5 May 2019, an individual of P. falcinellus with breeding feathers was observed in a farmland in Wolsan-ri, Seocheon-gun. Twelve days later, another one was identified in a farmland in Janghang-dong, Goyang-si, about 173 km north of Wolsan-ri. The observed birds fed and rested in the area and stayed for only a day. The individual birds spotted in South Korea in 2019 are conjectured to have come from either Southeast Asia or Australia, among areas located in East Asian-Australasian Flyway (EAAF). This is because P. falcinellus, a species with excellent dispersal capacity, forms a population in new areas during extreme environmental changes in their current habitats, especially droughts. For 2 years, P. falcinellus was observed to be migrating in spring; however, in the future, they may exhibit the same propensity for breeding and habitats as that of birds migrating in autumn. As it is a conspicuous species, effective detection of their arrival requires a survey system that classifies the country by habitat type and involves periodic and multiple observations by experts and citizens.

PM2.5 Simulations for the Seoul Metropolitan Area: (V) Estimation of North Korean Emission Contribution (수도권 초미세먼지 농도모사: (V) 북한 배출량 영향 추정)

  • Bae, Minah;Kim, Hyun Cheol;Kim, Byeong-Uk;Kim, Soontae
    • Journal of Korean Society for Atmospheric Environment
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    • v.34 no.2
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    • pp.294-305
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    • 2018
  • Quantitative assessment on the impact from North Korean emissions to surface particulate matter(PM) concentration in the Seoul Metropolitan Area (SMA), South Korea is conducted using a 3-dimensional chemistry transport model. Transboundary transport of air pollutants and their precursors are important to understand regional air quality in East Asian countries. As North Korea locates in the middle of main transport pathways of Chinese pollutants, quantifiable estimation of its impact is essential for policy making in South Korean air quality management. In this study, the Community Multiscale Air Quality Modeling System is utilized to simulate regional air quality and its sensitivity, using the Comprehensive Regional Emissions inventory for Atmospheric Transport Experiment 2015 and the Clean Air Policy Support System 2013 emissions inventories for North and South Korea, respectively. Contributions were estimated by a brute force method, perturbing 50% of North and South Korean emissions. Simulations demonstrate that North Korean emissions contribute $3.89{\mu}g/m^3$ of annual surface PM concentrations in the SMA, which accounts 14.7% of the region's average. Impacts are dominant in nitrate and organic carbon (OC) concentrations, attributing almost 40% of SMA OC concentration during January and February. Clear seasonal variations are also found in North Korean emissions contribution to South Korea (and vice versa) due to seasonal characteristics of synoptic weather, especially by the change of seasonal flow patterns.

Modification of Sea Water Temperature by Wind Driven Current in the Mountainous Coastal Sea

  • Choi, Hyo;Kim, Jin-Yun
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2003.11a
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    • pp.177-184
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    • 2003
  • Numerical simulation on marine wind and sea surface elevation was carried out using both three-dimensional hydrostatic and non-hydrostatic models and a simple oceanic model from 0900 LST, August 13 to 0900 LST, August 15, 1995. As daytime easterly meso-scale sea-breeze from the eastern sea penetrates Kangnung city in the center part as basin and goes up along the slope of Mt. Taegullyang in the west, it confronts synoptic-scale westerly wind blowing over the top of the mountain at the mid of the eastern slope and then the resultant wind produces an upper level westerly return flow toward the East Sea. In a narrow band of weak surface wind within 10km of the coastal sea, wind stress is generally small, less than l${\times}$10E-2 Pa and it reaches 2 ${\times}$ 10E-2 Pa to the 35 km. Positive wind stress curl of 15 $\times$ 10E-5Pa $m^{-1}$ still exists in the same band and corresponds to the ascent of 70 em from the sea level. This is due to the generation of northerly wind driven current with a speed of 11 m $S^{-1}$ along the coast under the influence of south-easterly wind and makes an intrusion of warm waters from the southern sea into the northern coast, such as the East Korea Warm Current. On the other hand, even if nighttime downslope windstorm of 14m/s associated with both mountain wind and land-breeze produces the development of internal gravity waves with a hydraulic jump motion of air near the coastal inland surface, the surface wind in the coastal sea is relatively moderate south-westerly wind, resulting in moderate wind stress. Negative wind stress curl in the coast causes the subsidence of the sea surface of 15 em along the coast and south-westerly coastal surface wind drives alongshore south-easterly wind driven current, opposite to the daytime one. Then, it causes the intrusion of cold waters like the North Korea Cold Current in the northern coastal sea into the narrow band of the southern coastal sea. However, the band of positive wind stress curl at the distance of 30km away from the coast toward further offshore area can also cause the uprising of sea waters and the intrusion of warm waters from the southern sea toward the northern sea (northerly wind driven current), resulting in a counter-clockwise wind driven current. These clockwise and counter-clockwise currents much induce the formation of low clouds containing fog and drizzle in the coastal region.

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Population Genetic Structure of the Korean Endemic Species, Iksookimia pacifica (Pisces: Cobitidae) Distributed in Northeast Korea (한국고유종 북방종개(어류강, 미꾸리과)의 집단유전학적 구조)

  • Jang, Sook-Jin;Ko, Myeong-Hun;Kwan, Ye-seul;Won, Yong-Jin
    • Korean Journal of Environment and Ecology
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    • v.31 no.5
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    • pp.461-471
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    • 2017
  • Population genetic studies of 10 groups of Iksookimia pacifica were conducted to investigate the genetic diversity and population genetic structure across its known range in South Korea. Population DNA sequences of one mitochondrial gene (mtCOI) and three nuclear genes (IRBP, EGR2B, RAG1) were examined in samples collected from ten streams that flow into the East Sea. Both mitochondrial and nuclear sequences exhibited significant differentiation among populations except a few cases. The Bayesian analysis of the multi-locus genotypes inferred from the DNA sequences of nuclear genes clustered the individual fish largely into two geographical groups: a northern group (from Baebong stream to Cheonjin stream) and a southern group (Yangyangnamdae stream to Gangneungnamdae stream). Given that the streams flowing into the East Sea are geographically isolated water systems, such separation of genotypes can be interpreted by the geographical separation of common ancestors into north and south that had colonized South Korea. Since the initial geographical separation of the ancestral population by north and south, the ancestral groups seem to have experienced further differentiation into the current genetic clusters through the physical isolation of streams by the East Sea in each region. It is notable that many individuals in the Jasan stream formed a genetic cluster with those of Yangyangnamdae and Gangneungnamdae streams which are distant from each other. In addition, mitochondrial gene showed low genetic differentiation between some neighboring populations and very low level of genetic diversity in several populations. The present population genetic study will provide valuable information for the conservation and management of the Korean endemic fish species, I. paicifica.

The Maritime Geography of Korea Strait: Suggested Nomenclature and Cartographic Boundaries Derived from a Review of Historical and Contemporary Maps (국제학술지, 지도, 문서에 나타난 대한해협 해양지명과 경계에 대한 인식 변화)

  • DO-SEONG BYUN;BYOUNG-JU CHOI
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.28 no.2
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    • pp.63-93
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    • 2023
  • This study aims to examine the history of naming the strait between the Yellow and East China Seas and the East Sea to suggest a consistent nomenclature and to demarcate the geographic region of the strait. Although the strait is internationally known as 'Korea Strait', it is commonly referred to as the 'South Sea' in Korean common usage. This review ultimately recommends the use of 'Korea Strait' as an appropriate geographical name for this area. To support this recommendation, the historical boundaries typically assigned to the Korea Strait were investigated. We also analyzed the evolution of geographical labels assigned to Korea Strait and to the Western and Eastern Channels (labels given to the two maritime areas surrounding Tsushima). Resources for this analysis included historic maps and charts, International Hydrographic Organization Special Publications (S-23), and maps published in the Ocean Science Journal (OSJ) and Journal of Oceanography (JO), which are two international journals representing Korean and Japanese sources, respectively, from 2005 to 2021. In these two international journals, the most frequently used names assigned to the strait of interest were Korea Strait (appearing 42.9% of OSJ maps, and 7.5% of JO maps), and Tsushima Strait (appearing 60.4% of JO maps, and 0% of OSJ maps). Other names were South Sea and Korea Strait/Tsushima Strait. On maps in the two reviewed journals, the boundaries of Korea Strait were defined explicitly or implicitly in five different ways: a broad region between the Yellow and East China Seas and Ulleung Basin (Type 1), the region between Ulleung Basin and Tsushima (Type 2), the western channel of the strait (Type 3-1), the eastern channel of the strait (Type 3-2), and both the western and eastern channels of the strait (Type 4). Overall, Type 1 was the most frequently used boundary, taking up 71.4% of OSJ and 60.4% of JO maps. Lastly, we suggest in this paper that the current flowing through Korea Strait from the East China Sea to the East Sea should be labeled the 'Korea Strait Warm Current' to indicate its full path through the strait. Currently, this current is internationally referred to as the 'Tsushima Warm Current', which does not link well to the commonly used geographic name of the strait.

A Study on Argopecten irradians Aquaculture in the North East Sea Regions (해만가리비 (Argopecten irradians) 의 동해 북부에서의 양식 연구)

  • Kim, Young Dae;Lee, Chu;Kim, Gi Seung;Park, Mi Seon;Park, Young Chel;kim, Young Suk;Yoo, Hyun Il
    • The Korean Journal of Malacology
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    • v.32 no.4
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    • pp.279-287
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    • 2016
  • NIFS conducted a feasibility study on the bay scallop Argopecten irradians aquaculture in the test site of Dongsanri, Yangyang-gun, Gangwon-do in June 2015. The transplantation for the test was also carried out in June. The average shell length was $5.79{\pm}0.6mm$ at the time, $15.83{\pm}0.8mm$ in July, $39.40{\pm}0.7mm$ in September, $55.72{\pm}5.8mm$ in November and $59.67{\pm}1.7mm$ in December. At the time of transplantation, the average shell height was $6.06{\pm}0.7mm$, and it grew to $16.40{\pm}0.9mm$ in July, $53.16{\pm}5.2mm$ in November and $55.80{\pm}2.9mm$ in December. Total weight was $0.78{\pm}0.5g$ in July but increased to $24.25{\pm}4.2g$ in November and $26.06{\pm}4.3g$ in December. The daily growth rate of shell length(DGR) was 0.33 mm / day in June, 0.43 mm / day in September and 0.13 mm / day in November. DGR of weight was 0.20 g / day in June, 0.27 g / day in September, 0.06 g / day in November. The relative growth of shell length and shell height was y = 0.9132x and $R^2=0.9923$. As a result, it was proved that bay scallop aquaculture is possible in Gangwon province, the northern part of the East Sea. This will definitely increase the income of fishermen by enabling them to culture more aquaculture species than the single large Patinopecten yessoensis in the region.