Interaction of the Kuroshio water and shelf waterin the Tsushima Current region in summer   总被引：2，自引：0，他引：2  

Guo Binghuo  Heung-Jae Lie  Jae Hak Lee 《海洋学报(英文版)》1998,17(3):277-292

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A Review on the Macromolecular Compositions of Phytoplankton and the Implications for Aquatic Biogeochemistry     

Bhavya  P. S.  Kim  Bo Kyung  Jo  Naeun  Kim  Kwanwoo  Kang  Jae Joong  Lee  Jae Hyung  Lee  Dabin  Lee  Jang Han  Joo  HuiTae  Ahn  So Hyun  Kim  Yewon  Min  Jun-Oh  Kang  Min Gu  Yun  Mi Sun  Kang  Chang Keun  Lee  Sang Heon 《Ocean Science Journal》2019,54(1):1-14

Ocean Science Journal - Biochemical composition of phytoplankton is a key indicator of the physiological and nutritional status of phytoplankton. A balanced biochemical pattern represents a healthy...  相似文献   

A seismic survey to detect natural gas hydrate in the East Sea of Korea     

Jeong?Hwan?LeeEmail author  Young?Soon?Baek  Byong?Jae?Ryu  Michael?Riedel  Roy?D.?Hyndman 《Marine Geophysical Researches》2005,26(1):51-59

Recently, several countries have conducted projects to explore and develop natural gas hydrate, which is one of the new alternative energy resources for the future. In Korea, a five-year national research project was initiated in 2000. As part of this project, a seismic survey was performed in the East Sea of Korea to quantify the potential magnitude and distribution of natural gas hydrates. Multi-channel seismic data and core samples have been acquired and recovered in the survey area. Analysis of seismic data show clear bottom simulating reflectors (BSRs), seismic blank zones (or wipe-out zones) with velocity pull-up structure, and pock-marks. In this study, we present the results of seismic surveys which indicate the existence of natural gas hydrates in Korean offshore areas. These results will be applied to select areas for coring (or drilling) and detailed exploration such as 2D seismic survey with long offset or 3D seismic in the future.  相似文献   

Spatial and temporal aspects of phytoplankton blooms in complex ecosystems off the korean coast from satellite ocean color observations     

Yu -Hwan Ahn  Palanisamy Shanmugam  Kyung- Il Chang  Jeong -Eon Moon  Joo -Hyung Ryu 《Ocean Science Journal》2005,40(2):67-71

Complex physical, chemical and biological interactions off the Korean coast created several striking patterns in the phytoplankton blooms, which became conspicuous during the measurements of ocean color from space. This study concentrated on analyzing the spatial and temporal aspects of phytoplankton chlorophyll variability in these areas using an integrated dataset from a Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Advanced Very High Resolution (AVHRR) sensor, and Conductivity Temperature Depth (CTD) sensor. The results showed that chlorophyll concentrations were elevated in coastal and open ocean regions, with strong summer and fall blooms, which appeared to spread out in most of the enclosed bays and neighboring waters due to certain oceanographic processes. The chlorophyll concentration was observed to range between 3 and 54 mg m^-3 inside Jin-hae Bay and adjacent coastal bays and 0.5 and 8 mg m^-3 in the southeast sea offshore waters, this gradual decrease towards oceanic waters suggested physical transports of phytoplankton blooms from the shallow shelves to slope waters through the influence of the Tsushima Warm Current (TWC) along the Tsushima Strait. Horizontal distribution of potential temperature (θ) and salinity (S) of water off the southeastern coast exhibited cold and low saline surface water (θ<19°C; S<32.4) and warm and high saline subsurface water (θ>12°C; S>34.4) at 75dBar, corroborating TWC intrusion along the Tsushima Strait. An eastward branch of this current was called the East Korean Warm Current (EKWC), tracked with the help of CTD data and satellite-derived sea surface temperature, which often influenced the dynamics of mesoscale anticyclonic eddy fields off the Korean east coast during the summer season. The process of such mesoscale anticyclonic eddy features might have produced interior upwelling that could have shoaled and steepened the nutricline, enhancing phytoplankton population by advection or diffusion of nutrients in the vicinity of Ulleungdo in the East Sea.  相似文献   

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

Dae Choul Kim  Gwang Hoon Lee  Young Kyo Seo  Gil Young Kim  Seok Yun Kim  Jeong Chang Kim  Soo Chul Park  Roy Wilkens 《Marine Georesources & Geotechnology》2004,22(1):21-31

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.  相似文献   

Potential of Argo Drifters for Estimating Biological Production within the Water Column     

SeungHyun Son  Emmanuel Boss  Jae Hoon Noh 《Ocean Science Journal》2006,41(2):121-124

Argo drifters provide information of the vertical structure in the water column and have a potential for the improvement of understanding phytoplankton primary production and biogeochemical cycles in combination with ocean color satellite data, which can obtain the horizontal distribution of phytoplankton biomass in the surface layer. Our examples show that using Argo drifters with satellite-measured horizontal distribution of phytoplankton biomass at the sea surface allow an improved understanding of the development of the spring bloom. The other possible uses of Argo drifter are discussed.  相似文献   

Weathering damage evaluation of rock properties in the Bunhwangsa temple stone pagoda,Gyeongju, Republic of Korea     

Chan Hee Lee  Jeong Eun Yi 《Environmental Geology》2007,52(6):1193-1205

The stone pagoda of the Bunhwangsa temple in Republic of Korea was made of piling small brick-shaped stones. The majority of stone bricks are andesitic rocks with variable geneses. Rock properties of the pagoda roof suffer partial significant deterioration, such as multiple peel-offs, exfoliation, onion-peel-like decomposition, cracks forming round lines and falling-off stone pieces. The stylobates and tabernacles at the four corners are composed of granitic rocks, which are heavily contaminated by lichens and mosses. Some of these contamination marks show dark black or yellowish brown colors by inorganic secondary hydrates. The four tabernacles and northern face of the pagoda body have been exposed to relatively high humidity, which causes light gray efflorescence as stalactites between the northern and western sides of the body. The efflorescences are composed of calcite, gypsum and clay minerals. The stone lion statues at the southeast and northeast corners are made of alkali granite, while the others are lithic tuff. Total rock properties of the pagoda consist of 9,708 stone bricks. Among them, 11.0% are fractured, 6.7% are fallen off, and 7.0% show considerable surface efflorescence, which shows that the pagoda has been highly deteriorated by physical, chemical and biological weathering. The authors strongly suggest long-term monitoring and comprehensive conservation researches.  相似文献   

Seismic test of a full‐scale model of a five‐storey stone pagoda     

Jae Kwan Kim  Hyeuk Ryu 《地震工程与结构动力学》2003,32(5):731-750

A moderate size earthquake of magnitude 5 occurred at Whagae‐Myun, Hadong‐Gun, Kyongsangnam‐Do, Korea on 4 July 1936. It caused severe damage to the buildings and other structures in Sang‐Gye‐Sa, a famous and beautiful Buddhist temple. A five‐storey stone pagoda was standing in front of Keumdang, the main building. The top component of the pagoda was tipped over and fell down to the ground during the earthquake. In order to have a quantitative estimate of the intensity of the earthquake, a full‐scale model was constructed through a rigorous verification process. The completed model was mounted on a shaking table and subjected to two kinds of dynamic test: exploratory test and fragility test. The exploratory test was performed with low intensity shaking. In the fragility test, the failure modes of the model were investigated while increasing the shaking intensity. The construction details of the model are described and test procedures are reported. Important relations between failure modes and characteristics of ground motion were obtained from the tests. The intensity of the 1936 earthquake was estimated from the examination of test results. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Probabilistic approach for active control based on structural energy     

Kyung‐Won Min  Jae‐Seung Hwang  Sang‐Hyun Lee  Lan Chung 《地震工程与结构动力学》2003,32(15):2301-2318

This paper presents an active control algorithm using the probability density function of structural energy. It is assumed that structural energy under excitation has a Rayleigh probability distribution. This assumption is based on the fact that the Rayleigh distribution satisfies the condition that the structural energy is always positive and the occurrence probability of minimum energy is zero. The magnitude of the control force is determined by the probability that the structural energy exceeds the specified target critical energy, and the sign of the control force is determined by the Lyapunov controller design method. The proposed control algorithm shows much reduction of peak responses under seismic excitation compared with the LQR controller, and it can consider the control force limit in the controller design. Also, the chattering problem which sometimes occurs in the Lyapunov controller can be avoided. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Abrupt light changes and multiperiodicity in Be stars: EW Lacertae revisited     

K. Pavlovski  Ž. RuŽić  M. Pavlović  J. H. Jeong  I. -S. NHA 《Astrophysics and Space Science》1993,200(2):201-210

The combined 1983 campaign and Seoul data on the variable Be star EW Lac is reanalyzed. CLEANing of the Fourier transform of the present time series clearly shows more than a single period. A multiperiodic fit can account also for a sudden brightness change through frequency beating. Comparison with previous multiperiodic solutions based on data obtained in different seasons shows highly variable amplitudes of the pulsational frequencies. The consequence of this finding to variable shell activity of EW Lac is briefly pointed out.Yonsei University Observatory Contribution No. 98.  相似文献