A hybrid near-field/far-field thermal discharge model for coastal areas   总被引：1，自引：0，他引：1  

Suh SW 《Marine pollution bulletin》2001,43(7-12):225-233

A hybrid technique has been used to simulate the dispersion of heat from surface discharges in coastal areas. Characteristics of the near field thermal dispersion are described by the CORMIX3 model. A two-dimensional harmonic finite element hydrodynamic model (TEA) and a Eulerian–Lagrangian transport model (ELA) are applied for the far-field computation. A Gaussian puff algorithm in ELA, which represents the near field plume as a series of patches, is used to link the two regimes. The computed results are compared to available field measurements. Very reasonable agreement is observed.  相似文献   

Effect of permeability–porosity functions on simulated morphological evolution of a chemical dissolution front          下载免费PDF全文

Keng‐Hsin Lai  Jui‐Sheng Chen  Chen‐Wuing Liu  Suh‐Yuh Yang 《水文研究》2014,28(1):16-24

  相似文献   

Development of updateable model output statistics (UMOS) system for air temperature over South Korea   总被引：1，自引：0，他引：1  

Jeon-Ho Kang  Myoung-Seok Suh  Ki-Ok Hong  Chansoo Kim 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(2):199-211

In this study, a Updateable Model Output Statistics (UMOS) system has been developed for the forecast of 3-h temperature over South Korea using two significantly different models’ (Regional Data Assimilation and Prediction System (RDAPS) and Korea Meteorological Administration (KMA) Weather Research and Forecasting (WRF) model (KWRF)) outputs based on the Canadian UMOS system (Wilson and Vallee, 2002; 2003). The UMOS system is designed to consider the local climatology and the model’s forecasting skills. The 20 most frequently selected potential predictors for each season, station, and forecast projection time from the 67 potential predictors of the Model Output Statistics (MOS) system, were used as potential predictors of the UMOS system. The UMOS equations are developed by a weighted blending of the new and old model data, with weights chosen to emphasize the new model data while including enough old model data in the development to ensure stable equations and a smooth transition to dependency on the new model. The UMOS equations were updated regularly at a predefined time interval to consider the changes of covariance structure between the new model output and observations as the new model data increase. The validation results showed that seasonal mean bias, Root Mean Square Error (RMSE), and correlation coefficients for the total forecast projection times are ?0.379～0.055°C, 1.951～2.078°C, and 0.741～0.965, respectively. Although, the forecasting skills of UMOS system are very consistent without regard to the season and geographic location, the performance is slightly better in autumn and winter than in spring and summer, and better in coastal regions than in inland region. When we take into account the significant differences of the RDAPS and KWRF, the UMOS system can be used as a supplementary forecasting tool of the MOS system for 3-h temperature over South Korea. However, the UMOS system is very sensitive to the selected number and/or types of predictors. Therefore, more work is needed to enable the use of the UMOS system in operation, including tuning of the number and types of potential predictors and automation of the updating processes of the UMOS equations.  相似文献   

National-scale assessment of landslide susceptibility to rank the vulnerability to failure of rock-cut slopes along expressways in Korea   总被引：2，自引：1，他引：1  

Jangwon Suh  Yosoon Choi  Tae-Dal Roh  Hyi-Jun Lee  Hyeong-Dong Park 《Environmental Earth Sciences》2011,63(3):619-632

The objective of this study is to perform a preliminary national-scale assessment of the landslide susceptibility of rock-cut slopes along expressways in Korea. A geographic information system (GIS) database was compiled based on data from topographical and geological maps, and rock-cut slope data, including the locations of past landslides. Seven factors (i.e., slope height, slope length, slope gradient, upper slope gradient, lithology, distance from nearest fault, and dip direction of slope) were extracted from the GIS database to assess the relationship between each factor and landslide events. Weight of evidence (WOE), analytic hierarchy process (AHP), and fuzzy logic methods, as well as hybrid methods, were used to establish the rating of classes for each factor, weightings for the factors, and to combine multiple factor layers into landslide-susceptibility maps. A comparison of the results obtained using several different methods, based on the area under curve technique, revealed that the WOE method showed the highest accuracy of 74%. The annual cost of traffic congestion resulting from slope failures was evaluated to identify those rock-cut slopes where detailed investigations and landslide warning systems are required.  相似文献   

Three-dimensional inversion of magnetotelluric data including sea effects obtained in Pohang, Korea     

Nuree Han  Myung Jin Nam  Hee Joon Kim  Tae Jong Lee  Yoonho Song  Jung Hee Suh   《Journal of Applied Geophysics》2009,68(4):533-545

Magnetotelluric (MT) surveys were conducted in Pohang, Korea, for low-temperature geothermal exploration in 2002 and 2003. Pohang is located in the southeastern part of the Korean Peninsula and close to the East Sea. In the interpretation of MT data from a coastal environment, sea effects must be correctly included because seawater is a strong conductor. We first constructed a five-layered earth model with a realistic coastline and bathymetry to investigate sea effects on MT data measured in Pohang. This model clearly shows that the Pohang data are significantly influenced by sea water at frequencies blow 1 Hz at the whole measurement sites. Next, we utilized a three-dimensional inversion algorithm based on the Gauss–Newton approach to produce a reliable resistivity model. Seawater is excluded from the inversion domain to fix the resistivity, while included in the modeling domain to simulate sea effects on MT responses. Blocks for the sub-seafloor are included in unknown parameters since they are sufficiently close to the survey area to affect MT responses in Pohang. Static shifts are also considered in inversion for more accurate interpretation. The rms data misfit is smoothly reduced from 11.2 to 1.87 after 7 iterations. The resulting resistivity model shows a pattern of low–high–low resistivity with depth. The model is compatible with resistivity logs obtained from four boreholes in the survey area, and can explain major geological features in Pohang.  相似文献   

对黄海-东海研究区深部结构的一些新认识   总被引：23，自引：7，他引：16       下载免费PDF全文

郝天珧  徐亚  胥颐  Suh Mancheol  刘建华  戴明刚  李志伟 《地球物理学报》2006,49(2):458-468

综合地震层析成像与重磁数据的处理结果,选择26°N～36°N,120°E～130°E的范围作为研究区,讨论了黄、东海研究区的深部结构特点及其与周边各地质单元的相互关系,完成了研究区两条剖面的密度结构反演,认为东海陆架地区地壳厚度变化与大陆地区相比并不明显,显著减薄开始于冲绳海槽地区,中地壳消失;琉球岛弧处地壳厚度明显再度增加,特别是上地壳的厚度增加最大,推断其原因应与俯冲作用及俯冲带附近板块与地幔的运动速率之差有关.地球物理场“东西分带”是黄海—东海地区壳内结构从西向东变化的反映,但随着深度的增加,研究区的岩石层结构出现以近EW向为优势的构造格局.因此推断深部近EW向的异常是三叠纪时期南北板块碰撞、挤压所致,浅部的NE向条带异常是后期构造运动在岩石层较浅部位构造效应的反映.黄海—东海地区岩石层结构存在浅部与深部优势构造方向不协调的现象.层析成像结果证实了南黄海东缘断层的存在,还勾绘出绍兴—十万大山碰撞带为以40°左右的倾角向NW方向倾斜的高速带,另一条倾向基本相同的高速带则是南、北扬子块体结合带在深部的反映.  相似文献   

Linear wave reflection by trench with various shapes     

Tae-Hwa Jung  Kyung-Duck Suh  Seung Oh Lee  Yong-Sik Cho 《Ocean Engineering》2008,35(11-12):1226-1234

Two types of analytical solutions for waves propagating over an asymmetric trench are derived. One is a long-wave solution and the other is a mild-slope solution, which is applicable to deeper water. The water depth inside the trench varies in proportion to a power of the distance from the center of the trench (which is the deepest water depth point and the origin of x-coordinate in this study). The mild-slope equation is transformed into a second-order ordinary differential equation with variable coefficients based on the longwave assumption [Hunt's, 1979. Direct solution of wave dispersion equation. Journal of Waterway, Port, Coast. and Ocean Engineering 105, 457–459] as approximate solution for wave dispersion. The analytical solutions are then obtained by using the power series technique. The analytical solutions are compared with the numerical solution of the hyperbolic mild-slope equations. After obtaining the analytical solutions under various conditions, the results are analyzed.  相似文献   

Delineation of Egyptian mud bricks using magnetic gradiometer techniques     

Ahmed El Emam  Tareq Abdallatif  Mancheol Suh  Hatem Odah 《Arabian Journal of Geosciences》2014,7(2):489-503

A near-surface magnetic gradiometer survey of a site at Hawara, Fayoum city is used to delineate archaeological features made by mud bricks at shallow depths in the northeast of the pyramid of Amenemhat III. Magnetic survey data were processed to a precise forward processing sequence, including clipping, de-sloping, removing stripes and edge discontinuities, de-spiking, filtering, interpolating, and finally detecting statistically significant results. The processed magnetic data indicate high amplitude anomalies in the northeastern part of the pyramid Amenemhat III, suggesting the presence of shallow cemeteries of mud brick walls. Low pass filtering of the vertical gradient data helped reveal the relatively deep mud brick features in the generally shallow section. These features were isolated using a statistical detection technique, and verified by the correlation with the surrounding mud brick discoveries. This required the analysis of the magnetic behavior of exposed mud bricks and man-made objects for comparison with the magnetic signature of buried material. These were then matched with the vertical magnetic gradients of the exposed mud brick features from here and three other Egyptian localities. They are mostly the extension of the 12th Dynasty cemeteries, which exist in the western and southwestern parts of the study area.  相似文献   

Systematic documentation of landslide events in Limbe area (Mt Cameroon Volcano,SW Cameroon): geometry,controlling, and triggering factors     

V. B. Che  M. Kervyn  G. G. J. Ernst  P. Trefois  S. Ayonghe  P. Jacobs  E. Van Ranst  C. E. Suh 《Natural Hazards》2011,59(1):47-74

Limbe town and surrounding areas, on the SE foot slopes of the active Mt Cameroon Volcano, have experienced numerous small-scale shallow landslides within the last 20 years. These resulted in the loss of ~30 lives and significant damage to farmland and properties. Landslides and their scars are identified in the field, and their geometry systematically measured to construct a landslide inventory map for the study area. Specific landslides are investigated in detail to identify site-specific controlling and triggering factors. This is to constrain key input parameters and their variability for subsequent susceptibility and risk modeling, for immediate local and regional applications in land-use planning. It will also enable a rapid exploration of remediation strategies that are currently lacking in the SW and NW regions of Cameroon. Typical slides within the study area are small-scale, shallow, translational earth, and debris slides though some rotational earth slides were also documented. The depletion zones have mean widths of 22 m ± 16.7 m and lengths of 25 ± 23 standard deviation. Estimated aerial extents of landslide scars and volume of generated debris range from 10¹ to 10⁴ m² and 2 to 5 × 10⁴ m³, respectively. A key finding is that most slope instabilities within the study area are associated with and appear to be exacerbated by man-made factors such as excavation, anarchical construction, and deforestation of steep slopes. High intensity rainfall notably during localized storms is the principal triggering factor identified so far. The findings from this case study have relevance to understanding some key aspects of locally devastating slope instabilities that commonly occur on intensely weathered steep terrains across subtropical Africa and in the subtropics worldwide and affecting an ever denser and most vulnerable population.  相似文献   

Seasonal and diurnal variations of stability indices and environmental parameters using NCEP FNL data over East Asia     

Hyo-Sik Eom  Suh Myoung-Seok 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(2):181-192

Seasonal and diurnal variations of commonly used stability indices (SIs) and environmental parameters (EPs) over East Asia were examined by using eight years (2000～2007) 6-hr National Centers for Environmental Prediction (NCEP) final (FNL) global reanalysis data. The quality of the FNL data was also evaluated by using the routine rawinsonde data over South Korea. Most of the SIs and EPs shows significant seasonal variation (SV) and diurnal variation (DV), but their magnitudes are dependent on the geographic locations and seasons. In general, the SV and DV of SIs and EPs are greater over the inland area than that over the waters around the Korean peninsula, and the magnitude of DV is significantly larger during summer than during other seasons. The mid-to-upper atmosphere of the East Sea also exhibits relatively stable conditions during the summer due to the extended Okhotsk sea air mass. As a result, the SIs and EPs of the summer show a “C” shape with a minimum instability over the East Sea. The spatial distribution of the SIs and EPs also shows that the eastern and south-eastern region of China is the most favorable for deep convection during the summer. The DV of SIs and EPs are more significant in the inland area than on the coast with maximum (minimum) at 0600 UTC (1800 UTC). Although the spatial distribution of DV pattern is well suited to that of rawinsonde data, the time of the maximum and minimum instability over South Korea does not correspond to that of the rawinsonde data, which occurred at 1200 UTC and 0000 UTC (Eom et al., 2008). Compared to the rawinsonde data, the FNL data have a large RMSE in the temperature, wind, and mixing ratio especially at the lower troposphere. Therefore, the FNL data should be used with caution, especially for the perfect boundary condition experiments with various numerical simulation models.  相似文献