Tidal dynamics in the strong tidal current environment of the Uldolmok waterway, southwestern tip off the Korean peninsula

Uldolmok waterway, located between an island off the southwestern tip of Korean peninsula and mainland, is famous for its strong tidal current that has a maximum current of about 6.0m/s. A series of field observations along with numerical modeling have been carried out in order to understand the tidal dynamics in terms of the force balance along the whole waterway and the energy balance in the narrowest part of the waterway. First, analysis of the ADCP current and the tide level variation data reveals that the tidal dynamics along the total waterway (channel) is balanced dominantly between the pressure gradient and linear bottom frictional forces, with the phase lag of sea level difference for the semi-diurnal constituents leading the current phase about by 10°. Secondly, the result of the numerical modeling reveals that the tidal energy flux vector flows toward the narrowest section, indicating that there should be related nonlinear processes. Through the numerical model experiment with multi-components, the convergence of (M₂ + S₂) tidal energy flux of 6.68 × 10⁷ Joule/s in the narrow area of the Uldolmok waterway is explained mainly by the energy consumption of 73% through the nonlinear generation of shallow water components and by the bottom frictional energy dissipation of 27%. This reveals that the remarkably strong nonlinear process dominates in the narrowest section of the Uldolmok waterway, compared with other areas, such as Yellow and East China Seas where the total M2 energy flux through the open boundary is balanced in terms of the bottom dissipation (Kang et al. 2003; Choi 1980).     

Geological consequences of the Saemangeum Dyke, mid-west coast of korea: A review

The Saemangeum Dyke is located in an estuarine setting, regulated in a complicated manner by a macrotidal regime, rivers, and winter monsoon. Accordingly, the constructed dyke resulted in a variety of artificial changes in geological characteristics in the estuary and its vicinity. To investigate those dyke-induced changes, the KORDI (Korea Ocean Research and Development Institute) performed sedimentological and sediment-dynamical observations from 2002 to 2010. On the basis of the KORDI results, the major geological changes and associated dynamical processes are reviewed. Five phenomena, among others, are focused on: depositional-channel creation; gap-related erosion; forced movements of surface sands; tidal-flat growth inside the dyke; and blanketing of mud over the sandy seafloor. These phenomena were unforeseen before the dyke construction, and reflect that the dyke could cause both erosion and deposition on an estuarine scale. The investigations conclude that the sediments in the dyke-influenced region were derived from the two rivers, Mangyeong and Dongjin, of the estuary. This is completely contrary to the offshore origin proposed before the dyke construction. As a result, the review supports the proposal that a thorough geological investigation and rational forecast is necessary prior to dyke construction to avoid economic loss and a fractious environmental debate.     

Improved water quality in response to pollution control measures at Masan Bay, Korea

The total pollution load management system (TPLMS) was first applied in 2007 to the highly developed Masan Bay watershed, Korea. To evaluate the effect of TPLMS on water quality improvement, we analyzed the water qualities in rivers and bay during 2005-2010, targeting chemical oxygen demand (COD), suspended sediment (SS), total nitrogen (TN), and total phosphorus (TP) loads. Land-based pollutant loading all decreased during this period, with a significant reduction in COD and SS loads (p<0.01). The COD reduction in seawater, following the TPLMS implementation, was also significant (p<0.01). Time-lagged responses in COD and Chl-a supported an estimated seawater residence time of ~1 month. Land-based nutrient loads were also significantly reduced for TN (p<0.01) and TP (p<0.05), however, significant reductions were not observed in the bay, indicating potential alternative nutrient inputs from non-point sources into the bay system.     

Rates of fluvial bedrock incision within an actively uplifting orogen: Central Karakoram Mountains, northern Pakistan

Terrestrial cosmogenic nuclide (TCN) ¹⁰Be surface exposure ages for strath terraces along the Braldu River in the Central Karakoram Mountains range from 0.8 to 11 ka. This indicates that strath terrace formation began to occur rapidly upon deglaciation of the Braldu valley at  11 ka. Fluvial incision rates for the Braldu River based on the TCN ages for strath terraces range from 2 to 29 mm/a. The fluvial incision rates for the central gorged section of the Braldu River are an order of magnitude greater than those for the upper and lower reaches. This difference is reflected in the modern stream gradient and valley morphology. The higher incision rates in the gorged central reach of the Braldu River likely reflect differential uplift above the Main Karakoram Thrust that has resulted in the presence of a knickpoint and more rapid fluvial incision. The postglacial fluvial incision rate (2–3 mm/a) for the upper and lower reaches are of the same order of magnitude as the exhumation rates estimated from previously published thermochronological data for the Baltoro granite in the upper catchment region and for the adjacent Himalayan regions.     

Ten new species of parasitic cyclopoid copepods (Crustacea) belonging to the families Bomolochidae, Philichthyidae, and Taeniacanthidae from marine fishes in Korea

Ten new species of cyclopoid copepods are described as parasites of marine fishes from Korea. Three new species of the family Bomolochidae are described as gill parasites: Orbitacolax pteragogi n. sp. from Pteragogus flagellifer (Valenciennes), Orbitacolax trichiuri n. sp. from Trichurus lepturus Linnaeus, and Orbitacolax unguifer n. sp. from Evynnis japonica Tanaka. Four species of the genus Colobomatus Hesse, 1873 of the family Philichthyidae are described as internal parasites: Colobomatus unimanus n. sp. from Pseudolabrus eoethinus (Richardson), Colobomatus recticaudatus n. sp. from Halichoeres poecilopterus (Temminck and Schlegel), Colobomatus floridus n. sp. from Hapalogenys mucronatus (Eydoux and Souleyet), and Colobomatus orientalis n. sp. from Johnius grypotus (Richardson). Three new species of the family Taeniacanthidae, including a new species belonging to a new genus, are described as gill parasites: Taeniacanthus singularis n. sp. from Halieutaea fumosa Alcock, Triacanthus luteus n. gen. n. sp. from Odontamblyopus lacepedii (Temminck and Schlegel), and Umazuracola geminus n. sp. from Stephonolepis cirrhifer (Temminck and Schlegel).     

Copepods of Hatschekiidae (Copepoda, Siphonostomatoida) new to Korean fauna, with description of a new species

Eight species of the Hatschekiidae are recorded as parasites of marine fishes from southern coast of Korea. One new species, Hatschekia jejuensis, parasitic on Cheilodactylus zonatus Cuvier is included. The remaining seven species are new to Korean fauna: Hatschekia iridescens Wilson, 1913, H. japonica Jones, 1985, H. monacanthi Yamaguti, 1939, H. tenuis (Heller, 1865) H. pseudolabri Yamaguti, 1953, H. cylindrica Shiino, 1957, and Pseudocongericola chefoonensis Yü, 1933. Hatschekia jejuensis n. sp. has a combination of characteristics in the female where the trunk is 2.35 times as long as the cephalothorax and displays a pair of posterolateral bulges on both sides, the antennules is 5-segmented, the mandible bears six teeth, and the armature formulae of the legs are I-0; III (exopod) and 0-0; II (endopod) for leg 1 and I-0; I (exopod) and 0-0; II (endopod) for leg 2.     

Derivation and assessment of a bivariate IDF relationship using paired rainfall intensity–duration data

A procedure is presented for developing a rainfall intensity–duration–frequency (IDF) relationship that is consistent with bivariate normal distribution modeling. The Box–Cox transformation was used to derive the relation and two methods of determining the parameters of this transformation were evaluated. To assess the uncertainty of the parameters, a confidence interval was constructed and verified with the non-parametric bootstrap method. Additionally, the effect of sample size on the bivariate normality assumption was examined. Case studies, based on data from significant gauge stations in Korea, were performed. The result shows that the use of the bivariate normal model as an IDF relationship is particularly recommended when the available data size is small.     

Retrieval of suspended sediment concentrations in large turbid rivers using Landsat ETM+: an example from the Yangtze River,China

Suspended sediment concentration (SSC) is a critical parameter in the study of river sediment transport and water quality variation, but traditional measurement methods are costly and time‐consuming. This paper is focused on presenting a methodology that may be useful in estimating SSC which is of key importance in process geomorphology and hydrology. In previous studies, remote sensing has been applied to estimate the SSC of sea waters as well as low turbid inland waters like lakes, reservoirs and short river reaches visible within a single Landsat satellite image coverage. Rivers, especially highly turbid large rivers, have largely been ignored. The dataset used in this paper includes measured SSC and multi‐temporal Landsat ETM+ images covering most part of the Yangtze River. Using an effective easy‐to‐use atmospheric correction method that does not require in situ atmospheric conditions, retrieved water reflectance of Band 4 was found to be a good SSC indicator within the large SSC range 22–2610 mg l^–1. The newly developed regression relation between SSC and water reflectance of Band 4 appears to be able to provide a relatively accurate SSC estimate directly from Landsat ETM+ images for the Yangtze River from the upper, the middle to the lower reaches. With the relation it is possible to estimate or map out SSC dynamics of large rivers which lack SSC data due to constraints of conventional measurements. Copyright © 2009 John Wiley & Sons, Ltd.     

Comparative analysis of four stem taper models for Quercus glauca in Mount Halla,Jeju Island,South Korea

This study was conducted to fit the diameter-height data of Quercusglaucain Jeju Island, South Korea to the four commonly used stem taper equations andto evaluate the performance of the four stem taper models using four statistical criteria： Fit index （FI）, root mean square error （RMSE）, bias （）,and absolute mean difference （AMD）. Results showed that the Kozak02stem taper equation provided the best FI（0.9847）, RMSE（1.5745）,（-0.0030 cm） and AMD （1.0990 cm） whileMax and Burkhart model had the poorest performance among the four stem taper models based on the four evaluation statistics （FI ： 0.9793,RMSE ： 1.8272, ： 0.3040 cm and AMD ： 1.3060 cm）. These stem taper equations can serve as a useful tool for forest managers in estimating the diameter outside bark at any given height, merchantable stem volumes and total stem volumesof the standing trees of Quercusglaucain theGotjawal forests located in Mount Halla, Jeju Island, South Korea.