Coast Of Korea Research Articles

Applicability Study of a Global Numerical Weather Prediction Model MPAS to Storm Surges and Waves in the South Coast of Korea

The south coast of Korea is vulnerable to coastal disasters, such as storm surges, high waves, wave overtopping, and coastal flooding caused by typhoons. It is imperative to predict such disastrous events accurately in advance, which requires accurate meteorological forcing for coastal ocean modeling. In this study, to acquire accurate meteorological data as important forcing variables for the prediction of storm surges and waves, we examined the forecast performance and applicability of a next-generation global weather/climate prediction model, the Model for Prediction Across Scales (MPAS). We compared the modeled surface pressure and wind with observations on the south coast of Korea for three typhoons that damaged Korea in 2020—Bavi, Maysak, and Haishen—and investigated the accuracy of these observations with the MPAS prediction. Those meteorological forcing variables were then used in the tightly coupled tide-surge-wave model, Advanced CIRCulation (ADCIRC) and the Simulating Waves Nearshore (SWAN) for the simulation of a typhoon-induced storm surge and wave. We also performed the hindcast of the wave and storm surges using a parametric tropical cyclone model, the best-track-based Generalized Asymmetric Holland Model (GAHM) embedded in ADCIRC+SWAN, to better understand the forecast performance and applicability of MPAS. We compared the forecast results of the typhoon-induced wave and storm surges with their hindcast in terms of the time-series and statistical indices for both significant wave height and storm surge height and found that wave and storm surge prediction forced by MPAS forecast provides a comparable accuracy with the hindcast. Comparable results of MPAS forcing with that of hindcast using best track information are encouraging because ADCIRC+SWAN forced by MPAS forecast with an at most four-day lead time still provides a reasonable prediction of wave and storm surges.

The complete mitochondrial genome of Trichoderma simmonsii (Hypocreales: Hypocreaceae) from the Southern Coast of Korea

Fungal species in the genus Trichoderma are widely used for industrial enzyme production and as biocontrol agents. In this study, we report the complete mitochondrial genome of a marine-derived Trichoderma simmonsii strain GH-Sj1, which belongs to the Harzianum clade of Trichoderma. GH-Sj1 was isolated from an edible sea alga Saccharina japonica collected from the southern coast of Korea. This newly assembled circular molecule is 28,668 bp in length and consists of 15 protein-coding genes, 26 transfer RNA genes, and two ribosomal RNA genes. Phylogenetic analysis using the maximum likelihood method shows that T. simmonsii GH-Sj1 is closely related to Trichoderma harzianum and Trichoderma lixii. To the best of our knowledge, this is the first characterization of a marine-derived mitogenome within the genus Trichoderma.

해묘를 놓고 있는 선박의 항법상 지위에 관한 고찰 - 해양안전심판원의 재결을 중심으로 -

Many vessels fishing in the waters of Far East Asia, including Korea, use bright fish-luring lights that are activated after laying sea anchor. Winter cutlass fishing vessels operate similarly to the cuttle fishing vessels in the Coast of Korea. The legal status of any vessel fishing while laying a sea anchor is not explicitly stipulated in the Convention on the International Regulations for Preventing Collisions at Sea, 1972 (hereafter referred to as ‘COLREG’) and the Maritime Safety Act. The Japan Maritime Casualty Tribunal classifies such fishing vessels as a power-driven vessel underway in accordance with sailing rules, and also a vessel laying sea anchor. However, the Korea Maritime Safety Tribunal judges it as a vessel at anchor, power-driven vessel underway, temporarily drifting vessel, vessel laying sea anchor, vessel restricted in her ability to manoeuvre or vessels engaged in fishing, and so on. In terms of the legal status of any vessels fishing while laying a sea anchor, the Korea Maritime Safety Tribunal has a common view that a sea anchor must be installed on the catching vessel for fishing purposes, with the vessel being restricted in her maneuverability as required by sailing rules. However, it is believed that they reached a different conclusion regarding the extent to which vessel fishing while laying a sea anchor impacts compliance with the sailing rules stipulated in COLREG and the Maritime Safety Act. In 2011, the Central Maritime Safety Tribunal judged that the No. 3 Sangmu which is fishing laying sea anchor, was a vessel engaged in fishing. However, the Regional Maritime Safety Tribunal determined otherwise, designating the vessel as a power-driven vessel underway(temporarily drifting vessel). This study analyzed marine accidents on vessels laying a sea anchor based on the judgments of Korea Maritime Safety Tribunal. As a result, from the point of view of legal stability and purpose, I suggested that the term “vessel laying sea anchor” should be defined newly and a vessel laying a sea anchor for fishing or waiting for fishing should be included in “vessel engaged in fishing” through the amendment of the Maritime Safety Act.

Load Resistance Factor for Vertical Caisson Breakwater in Korea

The load resistance factor according to the target reliability level was proposed using 16 vertical breakwaters constructed along the coast of Korea. Limit state functions for sliding and overturning limit states were defined. Reliability analysis was performed to obtain the sensitivity of the limit state function to the design variables. The partial safety factors of the design variable were obtained using the sensitivity, and the load resistance factor was calculated in turn. The representative value of load resistance factors was obtained by optimizing the load resistance factors for 16 vertical breakwaters, and it was verified that the breakwater designed using the representative value had a reliability index greater than the target value.

Simulation of Marine Leisure Accidents Using Random-Walk Particle Tracking on Macro-Tidal Environment

In the west coast of Korea (WCK), macro-tidal environments with wide tidal flats yield distinctive characteristics such as recursive tidal currents and tidal asymmetry. Here, we proposed an efficient search and rescue (SAR) computation method for WCK conditions (where bottom shapes affect nearshore sticking) using a finely resolved wet–dry circulation model. A random-walk particle tracking module (PTM) was applied to an unstructured finite element model to provide the SAR information needed to mitigate the consequences of marine leisure accidents. To capture the unique external forcing characteristics affecting the nearshore SAR case, sensitivity tests, which considered the characteristics of human bodies in particle representation, were performed on an idealized basin under typical external forcing. Furthermore, the effects of surface drag were included to represent real conditions more accurately. Our simulations showed that the accuracy of initial accident times for in situ mannequin floating tests (where several initial locations and times of accidents were used) directly affected the accuracy and effectiveness of SAR missions. However, to understand and predict the missing floating person in real time, additional intensive field experiments are required that account for the local geomorphological characteristics, external real-time temporal tides, and wind forcing incorporating extreme weather conditions.

An analytical model for beach erosion downdrift of groins: case study of Jeongdongjin Beach, Korea

Abstract. Beach erosion at the unprotected downdrift end of a groin is common with waves approaching the structure obliquely. This phenomenon has often occurred on the downdrift side of natural groins on the east coast of South Korea during high waves in winter months. The resulting planform assumes a distinctive crenulate shape with a maximum indentation point landward of the erosion. An analytical model is employed to study the beach erosion at the downdrift end of a natural rock groin at Jeongdongjin Beach in Korea, using mathematical equations derived from the parabolic model for headland-bay beaches in static equilibrium, to predict the downdrift control point and maximum indentation of the eroded shoreline. These equations are solved using the prevailing wave height, wave angle at breaking and wave direction derived from analyzing NOAA's wave data over 40 years and the longshore sediment transport rate calculated from the wave data. The location of the calculated maximum indentation is also verified using shoreline video monitoring data and compared with the result of a one-line numerical model for shoreline change. The limitation of the proposed analytical model is discussed as is the effect of sediment bypassing the groin.

The first national scale evaluation of total nitrogen stocks and burial rates of intertidal sediments along the entire coast of South Korea

The regulating ecosystem services, such as water purification, that tidal flats provide by nitrogen (N) burial are being increasingly recognized; yet, quantitative estimates remain limited. Here, we first present nationwide evaluation of total N stocks and burial rates in the Korean tidal flats, based on a 3 year long monitoring assessment combined with remote sensing approach. A total of 20 intertidal flats representing 7 provinces of South Korea were extensively surveyed in 2018–20. The sediment textural type (sand, mixed, and mud) classified from remotely sensed imagery was significantly correlated to that identified from field data (p < 0.01), warranting a nationwide estimate of total N stocks. The estimated total N stocks and burial rates in the tidal flats of Korea were 1.5 Tg N and 8,192 Mg N yr‐1, respectively. Total N stocks significantly varied by region, province, morphology, salinity, and land use type adjacent to the corresponding tidal flats. In general, the N stocks of tidal flats were influenced by the degree of terrestrial N inputs to the ocean. The N stocks were significantly correlated with several physical parameters, such as precipitation (p < 0.05) and tide (p < 0.01). Among the sediment properties, the mud content was found to be the key factor determining the total N stocks across the 20 intertidal flats (p < 0.01). Finally, by applying the environmental value for N removal (USD km‐2 yr‐1) to the tidal flat area (km2), the economic value of the total N removal was estimated as ~233 Million USD yr‐1 in Korea and ~15 Billion USD yr‐1 globally. Overall, the present work confirms the valuable ecosystem service of tidal flat's cost-efficient N removal capacity, highlighting marine ecosystem service.

Uncertainties Associated With Simulating Regional Sea Surface Height and Tides: A Case Study of the East China Seas

Modeling sea surface height (SSH) and tides is important but challenging in shelf seas. The Eastern China Seas (ECSs) is such a shelf sea with large inter-model deviations in prior studies. In order to assess and compare the possible uncertainty sources, numerical scenarios of varying the open boundary forcing, bottom roughness length scale, atmospheric forcing, grid resolution, and regional bathymetry were conducted in a hydrodynamic model of the ECSs. Results indicate that bathymetry data and open boundary forcing with inadequate accuracy generate uncertainties in SSH and tides locally and throughout the basin. An increase in bottom roughness enhances tidal dissipation and shifts amphidromes to the left relative to the incoming Kelvin waves, causing SSH variations in the ECSs. Refining the model resolution from 4 to 2 km mainly affects nearshore SSH and tides due to minor changes in depicted coastlines. Using different reanalysis meteorological data appears more important on the episodic than annual scale. It is highlighted that some uncertainty sources have opposing effects on SSH or tides and counteract their individual biases, making it difficult to achieve a realistic simulation. For example, increasing bottom roughness can not only compensate effects of overestimated tidal amplitude at open boundaries, but also balance out the overestimated M2 phase along the West Coast of Korea in a coarser-resolution model. Based on findings in this study, suggestions are provided for further reducing uncertainties in SSH and tide modeling in the ECSs and other shelf seas.

10 years long-term assessment on characterizing spatiotemporal trend and source apportionment of metal(loid)s in terrestrial soils along the west coast of South Korea

Long-term trends in the spatial distributions and sources of metal(loid)s in soils adjacent to the west coastal areas of South Korea have been systematically investigated for 10 years (2010–2019). Monitoring in 17 sites clearly showed site- and region-specific distributions, being associated with land use type (significant differences, as road > agriculture > wild) (P < 0.05), rather than temporal variation. The great concentrations of all metal(loid)s were found near Lake Shihwa (LS) and Geum River (GG), near the road, indicating that transportation activity was the main source of metal(loid)s contamination in soil. Especially, Cd (0.5 mg kg−1), Hg (0.04 mg kg−1), Pb (65 mg kg−1), and Zn (184 mg kg−1), related to the transportation activity near the road, showed twice greater than other land use types, on average. The concentration of metal(loid)s in each site and with the same land use type did not greatly vary over the years, with no significant annual difference (P > 0.05). The degree of metal(loid)s contamination compared to the background levels was identified in the order of Pb > Zn > Cr > Cu > As>Cd > Ni > Hg, with the contaminated hotspots mostly in LS or GG. The potential ecological risk was evidenced for Cd and Hg, but such a trend was temporally irregular over the years, indicating site-specificity. The sources of metal(loid)s were carefully determined as natural (20%), fuel combustion & agricultural pollution (43%), and vehicular emissions (37%) using the Positive Matrix Factorization model. The relative contribution of each source to contamination over the last decade was found to be similar, supporting that site-dependent lesser variation in metal(loid)s contamination in the coastal areas of South Korea. Overall, the distribution of metal(loid)s in the soil near the west coastal areas over the last decade largely depended on land use activities, and contamination degree was associated with non-point sources, such as transportation and fuel combustion.

Flow cytometric characterization of the hemocytes of sea hares from tidal pools in Jeju Island off the south coast of Korea

The members in the family Aplysidae known as sea hares play a crucial role as a grazer in small tidal pools or shallow subtidal hard bottoms. Like other marine gastropods, hemocyte types and functions of sea hares are limitedly known. This study identified and characterized the hemocytes of common Aplysia species Aplysia kurodai, A. juliana, and A. oculifera in rocky tidal pools in Jeju Island off the south coast of Korea using flow cytometry and light microscopy. The flow cytometry identified three different hemocytes in the hemolymph of the three sea hare species: granulocytes, hyalinocytes, and blast-like cells. The granulocytes exhibited pseudopodia on the cell surface and granules in the cytoplasm. Morphology of the hyalinocyte was similar to that of the granulocytes, while they lack cytoplasmic granules. The blast-like cells were small and round, with very thin cytoplasm. The hyalinocytes were the most abundant in the hemolymph, accounting for 89.8–92.6% of the total hemocytes. Flow cytometry indicated that the granulocytes and blast-like cells were less than 5.6% and 5.4% of the total hemocyte populations. Flow cytometry also revealed that the granulocytes and hyalinocytes are engaged in cellular defensive activities such as intra-cellular lysosomal content, phagocytosis, and ROS production. The mean lysosomal contents of the granulocytes (0.4 × 105–0.2 × 105 A U.) were 2–3 times higher than that of hyalinocytes (0.2 × 105–0.6 × 105 A U.). In addition, the ROS production of the granulocytes (0.98 × 106–1.95 × 106 A U.) was about twice higher than that of the hyalinocytes (0.62 × 106–1.14 × 106 A U.). Of the three species of sea hares, the granulocytes showed comparatively higher phagocytosis capacity (70.4–92.3%) than that of the hyalinocytes (34.8–46.0%). Flow cytometry and microscopy indicated that the hemocyte types and their functions were identical, regardless of the species.

Surface Warming Slowdown With Continued Subsurface Warming in the East Sea (Japan Sea) Over Recent Decades (2000–2014)

The long-term surface warming trend in the East Sea (Japan Sea; ES hereafter) stalled from 2000 to 2014 (−0.05°C yr−1, surface warming slowdown), while the subsurface (100–300°m) warming trend continued (+0.03°C yr−1). To address the processes underlying these contrasting trends in surface and subsurface temperature change, the trends in sea-level anomaly, isopycnal depth, and wind pattern were analyzed using monthly mean ocean reanalysis system 4 (ORAS4) data. During this period, the strengthened northwesterly/northerly wind in the central part of ES is supposed to contribute to a negative (positive) wind stress curl to its west (east), corresponding to an anticyclonic (cyclonic) circulation in the west (east). Furthermore, the induced negative wind stress in the west appears to enhance the northward penetration of East Korean Warm Current (EKWC), the slowdown in its eastward meandering around 38° N from the Korea coast, resulting in warm water accumulation in the west with peak warm anomaly at relatively greater depth compared to peak cold anomaly in the east. Overall, these wind-driven changes in transport from west to east, wind stress curl induced horizontal divergence (convergence) and the associated upwelling (downwelling), causes surface warming to slow and subsurface warming to persist during 2000 to 2014.

Characteristics of Swell-like Waves in the East Coast of Korea Using Atmospheric and Wave Hindcast Data

The long-term trend of swell-like waves invading the east coast of Korea was identified by using observations and hindcast data from 1979 to 2016. We defined a swell-like wave as a wave with a height of 2 m and a peak period of 10 s on the basis of a literature review of human casualties and property damage in the region. In total, 179 swell-like wave cases were detected from 1979 to 2016, with 132 cases caused by extratropical cyclones (ETCs). The track density analysis indicated that the ETCs were mainly generated on the east coast of China, over the East/Japan Sea, and over the Kuroshio-Oyashio extension region and then moved northeast. This reflects the prevailing wind direction, which was the most significant factor in generating the swell-like waves. The number of swell-like waves has been significantly increasing since the 2000s. This increasing trend of swell-like waves is linked with the synoptic eddy activity with a correlation of 0.53. They were associated with the reversed meridional gradient of surface air temperature and the consequent negative vertical wind shear anomaly near 40° N.

Molecular characterization, expression profile, and antiviral activity of redlip mullet (Liza haematocheila) viperin.

Viperin is known to exhibit activity against RNA viral infection. Viral hemorrhagic septicemia virus (VHSV) is a negative-sense single-stranded RNA virus that causes severe loss in aquaculture species. Susceptible species include redlip mullets (Liza haematocheila), which has become an economically important euryhaline mugilid species in offshore aquaculture along the west coast of Korea. Although interferon-stimulated genes are suspected to act against VHSV, specific pathways or mechanisms of these antiviral actions in redlip mullets have not yet been established. In silico studies of the mullet viperin (Lhrsad2) revealed an S-adenosyl methionine binding conserved domain containing the 77CNYKCGFC84 sequence. In the tissue distribution, the highest levels of lhrsad2 expression were observed in the blood. When injected with poly(I:C), an approximately 17-fold upregulation (compared to the control) of viperin was detected in the blood after 24h. Furthermore, non-viral immune stimuli, including Lactococcus garvieae (L. garvieae) and lipopolysaccharide (LPS), that were injected into redlip mullets were not found to induce considerable levels of viperin expression. Subcellular analysis revealed that Lhrsad2 localized to the endoplasmic reticulum (ER). To investigate Lhrsad2's antiviral effects against VHSV, cells overexpressing lhrsad2 were infected with VHSV, and then the viral titer and viral gene expression were analyzed. Both assays revealed the potential of Lhrsad2 to significantly reduce VHSV transcription and replication. In brief, the current study illustrates the remarkable ability of viperin to weaken VHSV in redlip mullet.

Prediction of Shoreline Change for the Calculation of the Integrated Littoral Sediment Budget

The severe coastal erosions are being accelerated along the east coast of South Korea owing to the intermittent erosions and depositions caused by the imbalance between the effective sediment volume supplied from coasts and rivers and the sediment transport rate. Consequently, many studies are being conducted to develop coastal-erosion reduction measures. To accurately determine the cause of coastal erosion, the causes of the erosion and deposition should be accurately diagnosed, and a comprehensive evaluation system for the sediment transport mechanism in the watershed and sea while considering regional characteristics is required. In particular, realizing the evaluation of the effective sediment volume that flows from the river to the sea through observations is a highly challenging task, and various research and developments are required to realize it, as it is still in the basic research stage. The purpose of this study was to systematically analyze the comprehensive sediment budget for coastal areas. First, an analytical system was developed. Then, a shoreline model was constructed by considering the size of the mixed particles. The parameters required for developing the model were determined using the observation data to improve the shoreline model. A sediment runoff model was applied to evaluate the effective sediment volume supplied from the river to the sea, and the applicability of this model was evaluated by comparing it with the sediment supply volume according to the soil and water assessment tool model. The representative wave and the input parameters of the model were set using the observation data of several years. It was found that the prediction performance of the shoreline change model improved when the effective sediment volume was considered, and the particles of the sediment on the shore were assumed to comprise multiple sizes. In particular, the prediction performance improved when the balance of the sediment budget was adjusted by applying a groin having a structurally similar performance to take into consideration the geographic features of the Deokbongsan (island) in front of the river mouth bar. The model demonstrated a good performance in reproducing long-term shoreline changes when the characteristics of the sea waves and the effective sediment volume were considered.

Spatiotemporal Evaluation of Water Quality and Hazardous Substances in Small Coastal Streams According to Watershed Characteristics

In this study, spatial and temporal changes of eight water quality indicators and 30 types of hazardous substances including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, and inorganic matters for the small coastal streams along the West Coast of South Korea were investigated. In coastal streams with clear seasonal changes in water quality, larger watershed areas led to greater contamination by particulate matter (i.e., suspended solids, r = 0.89), and smaller watershed areas led to greater contamination by organic matter (i.e., BOD, r = −0.78). The concentration of VOCs and pesticides was higher in agricultural areas, and those of SVOCs and metals were often higher in urban areas. According to the principal component analysis (PCA), during the wet season, the fluctuation in the water quality of coastal streams was higher in urban areas than in agricultural areas. Furthermore, coastal streams in residential areas exhibited higher levels of SVOCs, and those in industrial areas exhibited higher levels of metallic substances. Based on these results, the spatial and temporal trends of water quality and hazardous substances were obtained according to watershed characteristics, thereby clarifying the pollution characteristics of small-scale coastal streams and the major influencing factors.

Measurements and Spatial Distribution Simulation of Impact Pile Driving Underwater Noise Generated During the Construction of Offshore Wind Power Plant Off the Southwest Coast of Korea

Offshore wind power plants are under construction worldwide, and concerns about the adverse effects of underwater noise generated during their construction on the marine environment are increasing. As part of an environmental impact assessment, underwater noise generated by impact pile driving was measured during the construction of an offshore wind farm off the southwest coast of Korea. The sound exposure levels of impact pile driving noise were estimated as a function of distance and compared with those predicted by a damped cylindrical spreading model and broadband parabolic equation simulation. Source level at 1 m was estimated to be in a range of 183–184 dB re 1μPa2s in the sound exposure level based on the model predictions and it tended to decrease by 21log⁡r as the distance increased. Finally, the spatial distribution of impact pile driving noise was predicted. This result, if combined with noise-induced damage thresholds for marine life, may be used to assess the effects of wind farm construction on marine ecosystems.

ВАГОВІ СИСТЕМИ ДАВНІХ ЦИВІЛІЗАЦІЙ КОРЕЇ ТА ЯПОНІЇ

Ancient civilizations in Central Asia and the Far East have appeared after a long period of developing social relations, material and spiritual culture of the population of this vast region of the Earth. In Central Asia, economic development was based on animal husbandry, and in the Far East, on land cultivation. Continuous growth of production and trade took place simultaneously with state formation that continued over millenniums. First proto – state formations of this region have created unified length, weight and volume measures that were indispensable for a successful economic development. The needs of trade necessitated the advent of monetary units that long have been closely related to weight measures. Gradually, every state saw the adoption of unified monetary – weight systems. It has long been known that the development of production and trade, social processes, state building takes place in those regions where several types of economy coexist. The type of farm is determined by natural conditions. There are several natural areas in the Far East. The first is the forest zone of Siberia and Primorie, where the population was engaged in hunting and forestry. The second – the area of steppes and deserts of Manchuria, Mongolia, the plateaus of Tibet, suitable for livestock. The third is the area of the Yellow River and Yangtze River valleys, where irrigated agriculture developed and the Chinese began cultivating rice for the first time in the world. Fourth – the area of the Yellow Sea coast, the coast of Korea, the Japanese islands, where the population was engaged in sea fishing and trade. In the interaction and complementarity of all these forms of economy arose the civilizations of the Far East. In the Far East, the geographical location of the Korean Peninsula is compared with Italy, the Japanese Islands – with England and Ireland. It is on the shores of navigable rivers, the Yellow Sea coast, the Korean Peninsula, the Japanese islands for thousands of years the most intensive development of production, domestic and foreign trade, and in modern times there was an industrial revolution. This work describes the development and mutual influence of weight systems used by ancient civilizations in Central Asia and the Far East in the course of international trade. Weight norms and their correlation with each other and with monetary denominations in every separate country have been determined.

Molecular and microscopic identification of Eomarteilia granula infection in Manila clam Ruditapes philippinarum off the south coast of Korea.

A report on the new species Eomarteilia (=Marteilia) granula infecting Manila clam Ruditapes philippinarum from Japan in 2014 suggests the possibility of E. granula infecting other Manila clam populations in the Northwest Pacific region, including Korea. In this study, we report the first infections by E. granula in Manila clams off the south coast of Korea. Histology revealed Marteilia-like plasmodia in the digestive tubule epithelia. Tissue imprints demonstrated that each parasite sporangium enclosed 4 spores and transmission electron microscopy (TEM) revealed ultrastructure of primary cells enclosing secondary cells, which contained spores. Mature spores consisted of 3 sporoplasms: outermost, intermediate, and innermost. The outermost sporoplasm showed a peripheral electron-dense monolayer characteristic of E. granula. The 18S rDNA amplified from the Marteilia-like parasite yielded 1784-bp PCR amplicon sequences which were 99.8% similar to that of E. granula previously reported (as M. granula) from Japan. In the molecular phylogenetic analysis, the novel Marteilia-like organism formed a well-supported clade with E. granula. Accordingly, we concluded that the novel Marteilia-like parasite that we found infecting some Korean Manila clams is Eomarteilia granula. Field surveys revealed that the infection was limited to clams of the south coast of Korea, with the prevalence ranging from 3.3 to 5.0%.

A New Species of Ophiura (Echinodermata, Ophiuroidea) from Miocene Deep-Sea Deposits in the Pohang Basin, Korea

Dense aggregations of articulated ophiuroids, in external mould preservation, were discovered in the middle Miocene Duho Formation (Yeonil Group) of Pohang City, near the southeast coast of Korea. These specimens are here described as a new species, Ophiura pohangensis, which differs from congeners in having long, slender oral papillae, and tiny quadrangular arm comb papillae. The new species constitutes the first well-identified example of the class Ophiuroidea in the fossil record of Korea. Aggregation density of the new species is similar to that of occurrences of both fossil and extant Ophiura sarsii sarsii across Japan.

PPK Kit를 활용한 드론 측량 분석

With the popularization of drones and the ease of use of the Global Navigation Satellite System (GNSS), drone photogrammetry for terrain information has been widely used. Drone photogrammetry enables the realization of high-accuracy three-dimensional topography for the entire area with less effort and time compared to the past direct survey using GNSS or total station. From 3-D topographic data, various topographical analysis is possible. To improve the accuracy of drone photogrammetry, direct GCP surveying in the field is essential, and the numbers and reasonable positioning of GCPs are very important. In the case of beaches or tidal flats on the west coast of Korea, the numbers and location of GCPs are important factors in efficient drone photogrammetry because of the size of the area, difficulties of movement, and the risk from tides. If the RTK (Real-time kinematic) or PPK (Post-processed kinematic) method is used, the increased accuracy of the drone''s location enables high-accuracy photogrammetry with a small number of GCPs. This study presents an efficient drone photogrammetry method in terms of time and economy by comparing and analyzing the results of drone photogrammetry using Non-PPK with low-cost PPK-Kit, based on the tests of various numbers and locations of GCPs in the university field including various slopes and structures like coastal terrain.