Three-dimensional hydrodynamic-eutrophication model (HEM-3D): application to Kwang-Yang Bay, Korea   总被引：9，自引：0，他引：9  

Park K  Jung HS  Kim HS  Ahn SM 《Marine environmental research》2005,60(2):171-193

The purpose of this paper is twofold: to describe the water quality model of Three-Dimensional Hydrodynamic-Eutrophication Model (HEM-3D) and to present an application of HEM-3D to a coastal system in Korea. HEM-3D, listed as a tool for the development of Total Maximum Daily Load by US Environmental Protection Agency, is a general-purpose modeling package for simulation of the flow field, transport, and eutrophication processes throughout the water column and of diagenetic processes in the benthic sediment. This paper describes the water quality model of HEM-3D with emphasis on its unique features. Excessive loadings of organic wastes have significantly deteriorated water quality conditions of Korean coastal waters. This paper presents an application of HEM-3D to Kwang-Yang Bay, a coastal system in Korea, which is one of the first water quality modeling efforts for Korean coastal waters accompanied by a relatively comprehensive field program. The current status of data availability for water quality modeling in Korea is discussed.  相似文献   

A finite element method for dynamic analysis of long slender marine structures under combined parametric and forcing excitations   总被引：2，自引：0，他引：2  

Han-Il Park  Dong-Ho Jung 《Ocean Engineering》2002,29(11):1313-1325

This paper presents a numerical analysis of lateral responses of a long slender marine structure under combined parametric and forcing excitations. In the development of the 3-D numerical program, a finite element method is implemented in the time domain using the Newmark constant acceleration method. Some example studies are performed for various water depths, environmental conditions and vessel motions. The relative amplitudes of combined excitations to a conventional forcing excitation are examined. The response amplitude of a combined excitation is much greater than that of a forcing excitation in the even number of instability regions of the Mathieu stability chart. The results demonstrate that a combined excitation needs to be considered for the accurate dynamic analysis of long slender marine structures subjected to a surface vessel motion.  相似文献   

A tension measurement method of a towing cable or a buoy cable     

Hae-Hoon Park 《Ocean Engineering》1993,20(2)

An indirect tension measurement method of a towing cable in midwater or a buoy cable is proposed using underwater acoustic positioning systems, etc., to give the in-water cable tension. The most simple and traditional cable tension measurement method is to apply a mechanical tension meter at the one end of the cable, but the method has limits in the aspects of continuous monitoring and manual operation. However, the technique in this study is to apply the Pode's analysis of the equilibrium configuration and tension of a flexible twine, in which the cable tension is given as a function of the geometric positions of both ends of the cable. A set of nonlinear integral equations is formulated and solved numerically by the Newton-Raphson method. Then the inclination angles and the tensions at the lower and the upper ends of the cable could be obtained. The derived method enables us to track a towed object, to measure the tension of a towing cable or a buoy cable and is also applicable to the remotely operated vehicle (ROV) tethered to a mother ship.  相似文献   

Chemical constraints on the petrogenesis of mildly alkaline lavas from Vestmannaeyjar,Iceland: the Eldfell (1973) and Surtsey (1963–1967) eruptions     

Tanya Furman  Fred A. Frey  Kye-Hun Park 《Contributions to Mineralogy and Petrology》1991,109(1):19-37

The Vestmannaeyjar archipelago is composed of alkalic lavas erupted at the southern end of the active, southward propagating, Eastern Volcanic Zone. Recent eruptions include the most primitive (Surtsey) and most evolved (Eldfell) compositions found in this area. We studied time-stratigraphic sample suites from both eruptions to characterize the magmatic environment of Vestmannacyjar. All samples are nearly homogeneous in radiogenic isotopic ratios (⁸⁷Sr/⁸⁶Sr 0.70304 to 0.70327;¹⁴³Nd/¹⁴⁴Nd 0.51301 to 0.50307;²⁰⁶Pb/²⁰⁴Pb 18.96 to 19.18;²⁰⁷Pb/²⁰⁴Pb 15.50 to 15.53;²⁰⁸Pb/²⁰⁴Pb 38.47 to 38.76; KH Park and A Zindler, in preparation). Compositional trends of lavas from the two eruptions are not consistent with fractionation in a near-surface environment, but indicate rather moderate pressure evolution of small magma batches. At Eldfell, mugearite lavas can be modeled by 30% closed-system fractional crystallization of olivine+plagioclase+clinopyroxene+Fe–Ti oxides from parental hawaiite. The phase proportions are consistent with an experimentally determined moderate pressure (8 kbar) cotectic in mildly alkaline systems (Mahood and Baker 1986). Compositional variations of Surtsey lavas can be modeled by crystallization of clinopyroxene+olivine+plagioclase+minor Fe–Ti oxides. The presence of sodic plagioclase megacrysts and clinopyroxene with 8 wt% Al₂O₃ in xenoliths from Surtsey lavas are consistent with a moderate pressure fractionation event. Based on major-element and REE data the most primitive Surtsey lavas formed by small degrees of melting of a lherzolite source. The alkaline nature of Vestmannaeyjar lavas is not the result of assimilation of lower crustal melts (cf. Oskarsson et al. 1985; Steinthorsson et al. 1985).  相似文献   

Statistical analysis of main and interaction effects during the removal of BTEX mixtures in batch conditions, using wastewater treatment plant sludge microbes     

E. R. Rene Ph.D.  M. S. Jo  S. H. Kim  H. S. Park Ph.D. 《International Journal of Environmental Science and Technology》2007,4(2):177-182

Biodegradation has proved to be a versatile technique to remediate benzene, toluene, ethyl benzene and xylene mixtures in contaminated soil and groundwater. In this study, a mixed microbial culture obtained from a wastewater treatment plant was used to degrade liquid phase ethyl benzene and xylene, at initial concentrations varying between 15 to 75 mg/l. Experiments were conducted according to the 2^k?1 fractional factorial design to identify the main and interaction effects of parameters and their influence on biodegradation of individual ethyl benzene and xylene compounds in mixtures. The removal efficiencies of these compounds varied between 2 to 90% depending on the concentration of other compounds and also on their interaction effects. A statistical interpretation of the results was done based on the Fishers variance ratio (F) and probability (P) values. Though all the main effects were found significant (P < 0.05) at the 5% confidence level, the interactions between benzene and toluene and benzene and xylene concentrations were also found to be statistically significant and play a major role in affecting the total ethyl benzene and xylene removal.  相似文献   

Use of vertical electrical soundings to delineate seawater intrusion in a coastal area of Byunsan,Korea     

Sung-Ho Song  Jin-Yong Lee  Namsik Park 《Environmental Geology》2007,52(6):1207-1219

To delineate spatial extent of seawater intrusion in a small experimental watershed in the coastal area of Byunsan, Korea, electrical resistivity surveys with some evaluation core drillings and chemical analysis of groundwaters were conducted. The vertical electrical sounding (VES) method was applied, which is useful to identify variations in electrical characteristics of layered aquifers. The drilling logs identified a three-layered subsurface including reclamation soil, weathered layer and relatively fresh sedimentary bedrock. The upper two layers are the main water-bearing units in this area. A total of 30 electrical sounding curves corresponded mostly to the H type and they were further divided into three classes: highly conductive, intermediate, and low conductive, according to the observed resistivity values of the most conductive weathered layer. In addition, groundwater samples from 15 shallow monitoring wells were analyzed and thus grouped into two types based on HCO₃/Cl and Ca/Na molar ratios with TDS levels, which differentiated groundwaters affected by seawater intrusion from those not or less affected. According to relationships between the three classes of the sounding curves and groundwater chemistry, locations of the monitoring wells with low HCO₃/Cl and Ca/Na ionic ratios coincided with the area showing the highly conductive type curve, while those with the high ratios corresponded to the area showing low conductive curve type. Both the low electrical resistivity and the low ionic ratios indicated effects of seawater intrusion. From this study, it was demonstrated that the VES would be useful to delineate seawater intrusion in coastal areas.  相似文献   

Detecting areal changes in tidal flats after sea dike construction using Landsat-TM images   总被引：1，自引：0，他引：1  

Moon Seong Kang  Sang June Im  Tae Il Jang  Seung Woo Park  Sang Min Kim 《Journal of Earth System Science》2007,116(6):561-573

The main objective of this study was to estimate changes in the area of tidal flats that occurred after sea dike construction on the western coast of South Korea using Landsat-TM images. Applying the ISODATA method of unsupervised classification for Landsat-TM images, the tidal flats were identified, and the resulting areas were quantified for each image. The area of tidal flats from a topographic map published in one year differs significantly from that shown in another, which appears to be attributable to the tide levels at the time of aerial photography. During the study period, the area of tidal flats, as estimated from Landsat-TM images, increased by 4.57 km² per year in the study areas. The tidal flats in the inner sea of Chunsu Harbor area increased by 200 m² per zone, while the accumulation for a number of inner sea areas within Asan Harbor area occurred at over 50m² per zone. The results of this research may serve as the basis of an environmentallyfriendly development plan for tidal flats.  相似文献   

The Early Tertiary chemical remagnetization in the Bakjisan Syncline, Korea: Its geotectonic implications     

Yong-Hee Park  Seong-Jae Doh  Dongwoo Suk 《Physics of the Earth and Planetary Interiors》2007,160(3-4):269-284

The Bakjisan Syncline is located in the northwestern part of the Taebaeksan Basin, Korea. New paleomagnetic data for the Upper Carboniferous–Lower Triassic Pyeongan Supergroup from the Pyeongchang area on the west limb of the Bakjisan Syncline have been obtained, and synthesized and compared with previous data from the Jeongseon area on the east limb of the syncline. A total of 350 specimens were collected from 21 sites to clarify the relationship between the spatial distribution of remagnetized areas and the thrust system in the Taebaeksan Basin. The characteristic remanent magnetization (ChRM) isolated from all samples was a remagnetized component acquired after tilting of the strata and carried by various magnetic minerals (magnetite, hematite and pyrrhotite). From rock magnetic studies, electron microscope observations and XRD analyses, the pervasive remagnetization is interpreted to be associated mainly with a fluid-mediated chemical remanent magnetization (CRM). This is consistent with the results of previous work in adjacent areas. The paleomagnetic pole position (88.3°E, 83.9°N, A₉₅ = 4.9°) from the Pyeongan Supergroup in the Bakjisan Syncline indicates that the timing of the remagnetization event is Early Tertiary times (i.e. Paleocene to Eocene) by comparison with reliable paleopoles from the Korean Peninsula. Early Tertiary CRMs are also reported from previous studies of an adjacent region within the northwestern part of the Taebaeksan Basin. In contrast, a primary remanent magnetization was reported in the southeastern part of the Taebaeksan Basin. This implies that the major thrust system (the Gakdong thrust) which separates the two regions has caused them to experience substantially different geologic histories since deposition of the strata. Since many thrusts with NS trend are observed in the northwestern part of the Taebaeksan Basin compared with the southeastern region, it appears that the remagnetizing fluids pervasively penetrated the northwestern part of the basin by utilizing the already well-developed thrust system.  相似文献   

Multi-designated geoparks face challenges in China’s heritage conservation     

WANG Lianyong National Park L  Southwest University  Chongqing  China 《地理学报(英文版)》2007,(2)

The author selects a thorny issue of doubled designations that bother pol- icy-makers, professional planners and managers in the field of conservation for protected areas. The analyzed case study areas cover 5 National Geoparks of China in Sichuan Prov- ince, 18 UNESCO Global Geoparks in China, and 219 World Heritage sites in China and 8 European nations. Through analysis and synthesis, the author concludes that doubled des- ignation, which also leads to unbalanced park distribution, is particularly prevalent in China other than in Europe. Therefore, on-site management agencies and related governments in China should carefully translate the doubled designations into responsibilities and harmoni- ous partnerships between all stakeholders in order to enhance the management effectiveness and avoid paper park phenomenon.  相似文献   

Reservoir siltation in the semi‐arid highlands of northern Ethiopia: sediment yield–catchment area relationship and a semi‐quantitative approach for predicting sediment yield     

L. Tamene  S. J. Park  R. Dikau  P. L. G. Vlek 《地球表面变化过程与地形》2006,31(11):1364-1383

Due to shortage of rainfall and its increasing variability, moisture stress is identified to be one of the most critical factors affecting agricultural productivity in the drylands of Ethiopia. To circumvent this problem, a strategy of supplemental irrigation through surface water harvesting was adopted by the government and several micro‐dams have been built in the semi‐arid parts of the country. However, the benefits from the water harvesting schemes are not sustainable because of rapid water storage loss due to siltation. There is, therefore, an urgent need for improved catchment‐based erosion control and sediment management strategies. The design and implementation of such strategies require data on the rate and magnitude of sediment deposition. To this end, reservoir surveys were conducted to estimate sediment deposition rate for 11 reservoirs identified to be representative of catchments in the Tigray region of northern Ethiopia. Two approaches were employed during the survey: one was based on measurement of sediment thickness in reservoirs while the other was based on comparing the original and existing topography of the reservoir‐beds. The average annual sediment yield estimated for the study sites was about 19 t ha^?1 y^?1. An equation of the type SSY = 3á36A^0á67 (with SSY = area specific sediment yield in t ha^?1 y^?1 and A = catchment area in km²) was also established for the study region, which is opposite to the ‘universal’ SSY–A relationship. In order to improve the sediment yield predictive capability of A, it was integrated with a factorial index that assesses the catchment's propensity to erosion and potential sediment yield. The effect of accelerated sediment deposition on water storage loss of reservoirs and possible controlling factors of the SSY–A relationship are outlined. The potential semi‐quantitative scoring approach to characterize catchments in terms of erosion sensitivity and the significance of the A‐index approach to predict SSY of similar catchments are also highlighted. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献