Identification and characterization of the encrusting materials in a coastal liquefied petroleum gas storage cavern

An examination was carried out of the encrusting materials on the seepage removal pumps in a bottom sump of an undersea liquefied petroleum gas (LPG) cavern. The studied cavern, constructed at 8 km off the western coast of Korea, facing the Yellow Sea, is at 130–150 m below the seabed. Since the first filling of the LPG into the cavern, it has suffered from the unexpected problem of a thick encrustation of unknown materials on the seepage removal pumps of the cavern. The XRD and XRF analyses revealed that the encrustation materials were mainly iron (hydro)oxides and carbonate mineral (aragonite). Based on the geological setting below the cavern site, it was inferred that iron oxides found in the Pleistocene sandy sediment and the Precambrian gneiss might be supplying ferrous iron to the cavern waters under an anaerobic condition, evidenced by low dissolved oxygen and negative redox potential in the cavern water. A significant change in the hydraulic condition near the pump intake and mixing the cavern water with oxic waters supplied through re-circulated seawater and terrestrial groundwater discharge, would precipitate the dissolved iron. Precipitation of the carbonate mineral is thought to have occurred due to over-saturation of calcium and bicarbonate, which may have resulted from the dissolution of cement grouting materials used during the undersea cavern construction and submarine groundwater discharge (SGD). This study reports the iron and carbonate precipitation in the man-made undersea cavern, which is affected by the surrounding hydrogeological condition and the SGD.     

A Numerical Study of Sea-Fog Formation over Cold Sea Surface Using a One-Dimensional Turbulence Model Coupled with the Weather Research and Forecasting Model

The formation mechanism of a cold sea-fog case observed over the Yellow Sea near the western coastal area of the Korean Peninsula is investigated using numerical simulation with a one-dimensional turbulence model coupled with a three-dimensional regional model. The simulation was carried out using both Eulerian and Lagrangian approaches; both approaches produced sea fog in a manner consistent with observation. For the selected cold sea-fog case, the model results suggested the following: as warm and moist air flows over a cold sea surface, the lower part of the air column is modified by the turbulent exchange of heat and moisture and the diurnal variation in radiation. The modified boundary-layer structure represents a typical stable thermally internal boundary layer. Within the stable thermally internal boundary layer, the air temperature is decreased by radiative cooling and turbulent heat exchange but the moisture loss due to the downward vapour flux in the lowest part of the air column is compensated by moisture advection and therefore the dewpoint temperature does not decrease as rapidly as does the air temperature. Eventually water vapour saturation is achieved and the cold sea fog forms in the thermal internal boundary layer.     

Holocene environmental changes on the east coast of Korea

We present a record of Holocene environmental change on the east coast of Korea, inferred using pollen, carbon-isotopic composition (??¹³C), total organic carbon, total sulfur, carbon/nitrogen ratios, particle size analysis and major element geochemistry in a sediment core from Soonpogae Lagoon. A multi-proxy paleoenvironmental approach had not previously been applied in Korea and allowed us to reconstruct climate and vegetation change, sea-level rise, lagoon development, and human impact on the east coast of Korea over the last 8,000?years. Evidence from Soonpogae Lagoon supports the following three conclusions: (1) As a drying trend prevailed on the east coast of Korea after ~5,900?cal?yr BP, chemical weathering weakened and herbaceous plants became more important than during the previous humid phase (Holocene Climate Optimum), (2) Sea-level rise on the east coast slowed dramatically about 6,800?cal?yr BP, resulting in low rates of sedimentation in Soonpogae Lagoon, and (3) Soonpogae Lagoon was almost completely isolated from the sea by sand barriers when human impact intensified ~2,100 BP.     

Effect of magnetic field on a shock-induced thermal instability

The effect of a magnetic field on a thermal instability has been studied in a radiatively cooling region behind an interstellar shock of moderate propagation velocity ( 10 km s^–1). It is shown that the presence of a magnetic field of a few microgauss is very effective in preventing the thermal instability from building-up density concentrations. In the absence of the magnetic field, the shock-induced thermal instability will amplify a pre-shock density inhomogeneity by more than an order of magnitude. However, in the field's presence, the amplified density contrast is shown to be only a factor 2. Implications for the trace of a sweeping broom in the Pleiades nebula are discussed.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Variations of amplitude, wavelength and phase velocity of plane progressing waves over uniformly sloping beaches

The mysterious variation of the amplitude of waves progressing towards the shore over sloping beaches has been clarified explicitly by linear theory. The phase velocity of the waves increases rapidly as the waves travel across the surf zone towards the shore, as does the wavelength. The phase of the waves near shore is nearly stationary if the beach slope is small. Hence the waves are not sinusoidal near shore but surge towards the shore if the slope is small.     

Distribution and Acoustic Characteristics of Shallow Gas in the Korea Strait Shelf Mud off SE Korea

Shallow gas in the Korea Strait shelf mud (KSSM) off SE Korea, revealed by high-resolution subbottom profiles, is associated with acoustic blanking, acoustic turbidity, seepages with plumes in the water column, and seafloor depressions. The acoustic blanking, characterized by strong, consistent top reflection and wipeout below, is most dominant. The seaward edge of the acoustic blanking zone generally coincides with the 100-m water-depth contour, suggesting that the water depth (the pressure) may control the distribution of shallow gas. The acoustic turbidity, characterized by diffuse top reflection, is a dark smear, partially blanking the data below. The seepages with plumes, characterized by vertical smearing and disturbed seafloor, are seen only along the shallowest, landward edge of the acoustic blanking zone. This may suggest that the decreased gas solubility at shallow water depths, caused by the lowered pressure, increases the volume of free gas in the sediments, facilitating the gas escape. The seafloor depressions, interpreted as pockmarks, are accompanied by cone-shaped acoustic masking, which is probably the reflection from a narrow vent of gas. The gas-related acoustic anomalies appear to occur mostly in the upper, recent mud of the KSSM. Neither permeable beds nor faults, which can act as vertical migration pathways for deep thermogenic gas, are evident in the recent mud. We interpret that the bacterial degradation of organic matter in situ is the main source for the gas in the KSSM. The upwelling off SE Korea may be an important source for the increased organic matter in the area.     

Year-to-year variation of cold waters around the korea strait

Year-to-year variation of bottom cold waters around the Korea Strait was investigated based on bottom temperatures measured by submarine telephone cable between Pusan, Korea and Hamada, Japan from 1982 to 1992. The characteristics of bottom temperatures could be divided into three different groups: the Korean side, the middle, and the Japanese side. Temperature drops in summer appeared in all the three regions implying the intrusion of cold waters into the Korea Strait. Significant decreases in the Korean side were observed in 1983, 1986, 1990, 1991, and 1992 when bottom temperatures were high in the middle. In contrast, bottom temperatures significantly decreased in the middle in 1985, 1988, and 1989 when the temperature drops in the Korean side were relatively small. This tendency for a negative relationship was also shown in the second mode of an EOF analysis. In the years when bottom temperatures significantly decreased in the Korean side, the cold water along the east coast of Korea expanded offshore and its temperature was low. On the contrary, cold water in the southern region of the Ulleung Basin developed in the years when bottom temperatures decreased considerably in the middle.     

Characterization of proteins in the muscle of<Emphasis Type="Italic">limanda yokohamae</Emphasis> from the masan bay,Korea

Increasing industrial development in the Masan Bay area of Korea over the past decades increased the risk for the survival of marine organisms in the bay area by the deterioration of the water quality. Since living organisms have the ability to adapt contamination-associated stimuli by the alteration of gene expression, changes in proteins can be used as an important criterion for assessing the levels of environmental conditions. In this study, therefore, alterations of the expression of proteins in the muscle ofLimanda yokohamae from Dukdong and Dotsum in the bay area were surveyed and characterized as compared with Haegumgang, which served as a control site. The results demonstrated that the twenty spots detected from Dukdong and Dotsum were similar to each other. Fifteen proteins were found to be predicted or undefined proteins, while five proteins were identified as heavy polypeptide 11 of myosin, apolipoprotein A-I, fibroblast growth factor 17b precursor, G protein-coupled receptor kinase 1 b and bonnie and clyde. These data suggest that local fish in the bay area have dysfunction in muscle physiology including contraction, lipid metabolism, proliferation and differentiation and nervous system.     

Thermal history of the Cretaceous Sindong Group, Gyeongsang Basin, Korea based on fission track analysis

ABSTRACT Apatite and zircon fission track (FT) analyses were carried out to reconstruct the thermal history of the Lower Cretaceous Sindong Group, which is the lowermost stratal unit of the Gyeongsang Basin, Korea. Zircon FT central ages show a wide range from 83 ± 5 to 157 ± 18 Ma, and single-grain age spectra have multiple age populations, whereas all apatites have very consistent FT ages of c . 60 Ma, suggesting a totally reset cooling age. Co-existence of both older and younger ages compared with the depositional age and relatively short mean track length indicate that the Sindong zircons were partially annealed. The Sindong Group was heated into the zircon partial annealing zone (ZPAZ) around 80 Ma, and cooled below the apatite closure temperature at c . 60 Ma. Based on the zircon FT results combined with vitrinite reflectance data, the maximum palaeotemperature to which the Sindong Group had been subjected can be inferred to be about 260 °C. Zircon FT data from a granite body that is in contact with the Sindong Group and sandstones close to the granite body indicate that thermal influence caused by Upper Cretaceous intrusive rocks was limited in close vicinity of the intrusion and that the major heat source of the Sindong Group was burial. The thickness of uplifted and eroded section is estimated to be about 7 km.     

Bismuth in the Atlantic and North Pacific: a natural analogue to plutonium and lead?

Bismuth has been analysed on samples from a vertical section from California to VERTEX IV, north of Hawaii, from a profile in the western Sargasso Sea and from an extensive suite of surface stations in the North and South Atlantic. Taken together with data from samples of Bermuda rain and from the Mississippi, Amazon and the Orinoco and its tributaries, a general outline of the processes controlling the Bi distribution in the ocean can be worked out. The dominant source in the open ocean is aeolian with the fluvial inputs being very small. Most of the aeolian input is probably derived from volcanoes; an anthropogenic flux may be important in the northwest Atlantic. Bismuth is scavenged in the mixed layer and regenerated at shallow depth to give a distribution in the northwest Pacific similar to that of^239,240Pu and anthropogenic Pb. Below 2 km the values are extremely low, in the range 20–50 fM, lower than the coexisting levels for²³²Th. The residence time of the element in the water column is sufficiently short that there are large concentration decreases between the Deep Waters of the Atlantic and Pacific. In the latter ocean, the element appears to reflect essentially one-dimensional processes.