• Atmosphere
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• v.18 no.3
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• pp.171-182
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• 2008

In this study, we analyzed the spatial and temporal distribution of wind resources over Korea based on hourly observational data recorded over a period of 5 years from 457 stations belonging to Korea Meteorological Administration (KMA). The surface and 850 hPa wind data obtained from the Korea Local Analysis and Prediction System (KLAPS) and the Regional Data Assimilation and Prediction System (RDAPS) over a period of 1 year are used as supplementary data sources. Wind speed is generally high over seashores, mountains, and islands. In 62 (13.5%) stations, mean wind speeds for 5 years are greater than $3ms^{-1}$. The effects of seasonal wind, land-sea breeze, and mountain-valley winds on wind resources over Korea are evaluated as follows: First, wind is weak during summer, particularly over the Sobaek Mountains. However, over the coastal region of the Gyeongnam-province, strong southwesterly winds are observed during summer owing to monsoon currents. Second, the wind speed decreases during night-time, particularly over the west coast, where the direction of the land breeze is opposite to that of the large-scale westerlies. Third, winds are not always strong over seashores and highly elevated areas. The wind speed is weaker over the seashore of the Gyeonggi-province than over the other seashores. High wind speed has been observed only at 5 stations out of the 22 high-altitude stations. Detailed information on the wind resources conditions at the 21 stations (15 inland stations and 6 island stations) with high wind speed in Korea, such as the mean wind speed, frequency of wind speed available (WSA) for electricity generation, shape and scale parameters of Weibull distribution, constancy of wind direction, and wind power density (WPD), have also been provided. Among total stations in Korea, the best possible wind resources for electricity generation are available at Gosan in Jeju Island (mean wind speed: $7.77ms^{-1}$, WSA: 92.6%, WPD: $683.9Wm^{-2}$) and at Mt. Gudeok in Busan (mean wind speed: $5.66ms^{-1}$, WSA: 91.0%, WPD: $215.7Wm^{-2}$).

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.444-454
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• 2015

Measurements of bottom backscattering strengths in a frequency range of 6-14 kHz were made on the shallow water off the southern Gyeonggi Bay in Yellow Sea in May 2013, as part of the KIOST-HYU joint acoustics experiment. Geological surveys for the experimental area were performed using multi-beam echo sounder, sparker system, and grab sampling to investigate the bottom topography, sub-bottom profile and composition of surficial sediment, respectively. In this paper, the backscattering strengths as a function of grazing angle (in range of $28^{\circ}{\sim}69^{\circ}$) were estimated and compared to the predictions obtained by Lambert's law and APL-UW scattering model. Finally, the effects of geoacoustic parameters corresponding to the experimental area on the backscattering strengths are discussed.

• Atmosphere
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• v.16 no.4
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• pp.319-332
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• 2006

This study examines the capability of the WRF (Weather Research and Forecasting) model in reproducing heavy rainfall that developed over the Korean peninsula on 26-27 June 2005. The model is configured with a triple nesting with the highest horizontal resolution at a 3-km grid, centered at Yang-dong, Gyeonggi-province, which recorded the rainfall amount of 376 mm. In addition to the control experiment employing realistic orography over Korea, two consequent sensitivity experiments with 1) no orography, and 2) no land over Korea were designed to investigate orographic effects on the development of heavy rainfall. The model was integrated for 48 hr, starting at 1200 UTC 25 June 2005. The overall features of the large-scale patterns including a cyclone associated with the heavy rainfall are reasonably reproduced by the control run. The spatial distribution of the simulated rainfall over Korea agreed fairly well with the observed. The amount of predicted maximum rainfall at the 3-km grid is 377 mm, which located about 50 km southeast from the observed point, Yang-Dong, indicating that the WRF model is capable of predicting heavy rainfall over Korea at the cloud resolving resolutions. Further, it was found that the complex orography over the Korean peninsula plays a role in enhancing the rainfall intensity by about 10%. The land-sea contrast over the peninsula was fund to be responsible for additional 10% increase of rainfall amount.

• Journal of Korean Society of Forest Science
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• v.95 no.5
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• pp.562-568
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• 2006

This study was conducted to examine the energy content and photosynthetic efficiency of Quercus mongolica stands in Korea. Study sites were located in Mt. Joongwang, Gangwon-do (1,000 m and 800 m above sea level), Mt. Baekwoon, Jeollanam-do (800 m a.s.l.), Mt. Halla, Jeju-do (1,000 m a.s.l.), Mt. Taehwa, Gyeonggi-do (350 m a.s.l.), and Mt. Wolak, Chungcheongbuk-do (300 m a.s.l.). Total energy content and annual energy accumulation in Q. mongolica stands were 2,916-6,435 GJ/ha and 284-441 GJ/ha, respectively. Lower latitude (N.L.) stands of Q. mongolica showed higher energy contents than higher latitude stands, but Quercus stands in Mt. Baekwoon had higher annual energy accumulation than those in Mt. Halla located at a lower latitude. During the growing season, the photosynthetic efficiency of 60 to 70-year-old Q. mongolica stands ranged from 1.19 to 1.34% while that of 35-year-old stands did from 1.87 to 1.95%. There were no significant differences in photosynthetic efficiency among the latitudes because solar radiation was higher in low latitudes.

• Economic and Environmental Geology
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• v.47 no.1
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• pp.39-48
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• 2014

In coastal region, estuaries have complex environments where dissolved and particulate matters are mixed with marine water and substances. Suspended sediment (SS) dynamics in coastal water, in particular, plays a major role in erosion/deposition processes, biomass primary production and the transport of nutrients, micropollutants, heavy metals, etc. Temporal variation in suspended sediment concentration (SSC) can be used to explain erosion/sedimentation patterns within coastal zones. Remotely sensed data can be an efficient tool for mapping SS in coastal waters. In this study, we analyzed the variation in SSC in coastal water using the Geostationary Ocean Color Imager (GOCI) and Landsat Enhanced Thematic Mapper Plus (ETM+) in Gyeonggi-bay. Daily variations in GOCI-derived SSC showed low values during ebb time. Current velocity and water level at 9 and 10 am is 37.6, 28.65 $cm{\cdot}s^{-1}$ and -1.23, -0.61 m respectively. Water level has increased to 1.18 m at flood time. In other words, strong current velocity and increased water level affected high SSC value before flood time but SSC decreased after flood time. Also, we compared seasonal SSC with the river discharge from the Han River and the Imjin River. In summer season, river discharge showed high amount, when SSC had high value near the inland. At this time SSC in open sea had low value. In contrast, river discharge amount from inland showed low value in winter season and, consequently, SSC in the open sea had high value because of northwest monsoon.

• Korean Journal of Ichthyology
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• v.33 no.2
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• pp.117-125
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• 2021

According to the character states of nostrils in the Barbatula species comprising 1,366 specimens collected from the major river system in Korea, distribution pattern of the two Korean Barbatula species was reviewed. The taxonomic character related to nostrils in Barbatula was very stable and two character states (widely separated and closely set) were observed in the present materials. B. toni (Dybowski, 1869) with widely separated nostrils distributes in the streams flowing into the East Sea north of Sokcho, Gangwon-do Province; Eogokcheon Stream, a tributary of Namhangang River; and Anseongcheon Stream, Gyeonggi-do Province, whereas B. nuda (Bleeker, 1864) with closely set occurs in most rivers flowing into the Yellow Sea including Nakdonggang River as well as in the Yangyangnamdaecheon Stream, Gangwon-do Province south to Bangyulcheon Stream, Gyeongbukdo Province, flowing into the East Sea as previously reported with some exception. Especially, both Barbatula species were co-occurred in the Yeongokcheon Stream, Gangwon-do Province and Eogokcheon Stream. The present results will provide a useful guide to study the regional fish fauna or fish community analysis as well as to clarify the taxonomical status of the Korean Barbatula species.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.185-193
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• 2018

From 2017 to 2018, the disease has been monitored at four culturing eel farms in Incheon and Gyeonggi region in Korea. As a result, diseases with gill congestion frequently occurred. This disease occurred regardless of size of eel, but the frequency and cumulative mortality were high in eels within 3 months after stocking. The infected fish showed pathological histopathological features such as intense congestion and dilation in the central venous sinus (CVS) of gill filaments and hemorrhages in liver and kidney. Hexagonal viral particles measuring about 70 nm in diameter was observed in nuclei and cytoplasm of gill vascular endothelial cells. Molecular biologic diagnosis by both PCR and genetic analysis has been revealed that the causative agent of this disease is Japanese eel endothelial cells-infecting virus (JEECV), the cause of viral endothelial cell necrosis of eel (VECNE), which is mainly reported in Japan. This study is the first report on the characteristics of JEECV and VECNE infection in domestic eel farms.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.158-163
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• 2023

This study aimed to determine mercury (Hg), methylmercury (MeHg), and selenium (Se) levels in deep-sea fishes distributed in Gyeonggi-do, South Korea. Concentrations of Hg, MeHg, and Se were measured by using a mercury analyzer and Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The average content (mg/kg) in the seafood samples was as follows: Hg, 0.7647 (0.0182-5.3620), MeHg, 0.0764 (0.0096-0.8750), and Se, 0.4728 (0.1075-3.5100). All the levels of MeHg were below the recommended standards of the Ministry of Food and Drug Safety i.e., <1.0 mg/kg. Recent studies have shown that Se prevents Hg toxicity. The average daily intake in humans was 3.3 ㎍/kg, which was lower than the recommended amount (50-200 ㎍/person/day). The weekly intake of Hg and MeHg was calculated to be 6.07% and 1.90%, respectively, of the provisional tolerable weekly intake (PTWI). This study showed that the weekly intake of Hg and MeHg from abyssal fish was less than the PTWI recommended by the Joint FAO/WHO expert committee on food additives. Therefore, the levels reported in this study are presumed to be adequately safe.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.500-509
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• 2021

This study investigated the characteristics of a macrobenthos community and sediment environment and assessed the health of tidal flats along the west coast of Korea. A survey was conducted from Ganghwa-do to Mokpo, Jeollanam-do in April (spring) and August (summer) 2017, and April (spring) 2018. The sediment grain sizes in the Chungcheongnam-do region were coarser, and the sediment in the Gyeonggi-do·Incheon, Jeollanam-do, and Jeollabuk-do regions were finer. A total of 140 macrobenthic species were collected from this study and using a cluster similarity analysis of the macrobenthos community, they were divided into four groups. Group2 was associated with Manila clam farm stations, and Ruditapes phillipinarum, Nephtys polybranchia and Lumbrineris nipponica were dominant. Group4 included some sites with finer sediment composed relatively, and Eteone longa and Nemertea unid. appeared at a high frequency. From the health assessment of the western tidal flat, the ISEP and BHI indices had a "High status," and the AMBI index had a "Good status." In conclusion, the tidal flats along the west coast of Korea have good ecological health. However, pollution indicator species such as Theora lata and Capitella capitata have appeared in some areas. Therefore, periodic administration and interventions are necessary to prevent deterioration of the tidal flat environment.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.755-769
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• 2020

In 2019, about 134 million ㎥ of aggregate was produced in an estimated 880 quarries and pits in 17 metropolitan governments. Leading producing metropolitan cities were Gyeonggi-do, Gyeongsangnam-do, Chungcheongbuk-do, Gangwon-do, Gyeongsangbuk- do, Chungcheongnam-do, in order decreasing volume, which together accounted for about 71% of total product. Of the total domestic aggregates produced in 2019, about 31 % was sand and about 69% was gravel. It estimated that of the 134 million ㎥ of aggregates in Korea in 2019, about 50.3% was produced by screening crushed aggregate by 41.4% by forest aggregate, 3.3% by land aggregate, 1.7% by sea aggregate and 1.7% by washing each other, and 0.7% by river aggregate. This indicates that screening crushed aggregate and forest aggregate are the main producers of domestic aggregates. The most crushed and forest aggregate was extracted at the Gyeonggi-do and Gyeongsangnam-do, respectively. Land aggregate was mainly extracted at Gyeongsangbuk-do and Gangwon-do. Therefore, in the future supply and demand of aggregate resources, it is judged that there should be a primary policy direction for screening crushed and forest aggregate.