香港现代海平面变化及其影响     

严维枢 《热带地理》1997,17(2):173-178

潮汐站资料分析表明香港地区海平面每年以１ｍｍ的速度上升。然而，在沿海填海地区，由于受长期地面沉陷的影响，下沉速度超过上升速度，导致海平面明显相对上升。受大规模地面沉陷的影响。填海区在台风暴潮期间极易受海水浸淹。为了有助于未来海岸的开发，建议利用现有技术水平的测量方法，包括卫星测高和激光测距方法等，对填海区进行长期连续的地面沉陷监测。对下沉问题提出预警，以便采取措施，如修筑海提，建抽水站等，以抵御海  相似文献   

Earthquake response of structures with partial uplift on winkler foundation     

Chik-Sing Yim  Anil K. Chopra 《地震工程与结构动力学》1984,12(2):263-281

The effects of transient foundation uplift on the earthquake response of flexible structures are investigated. The structural idealization chosen in this study is relatively simple but it incorporates the most important features of foundation uplift. In its fixed base condition the structure itself is idealized as a single-degree-of-freedom system attached to a rigid foundation mat which is flexibly supported. The flexibility and damping of the supporting soil are represented by a Winkler foundation with spring-damper elements distributed over the entire width of the foundation. Based on the response spectra presented for several sets of system parameters, the effects of foundation-mat uplift on the maximum response of structures are identified. The influence of earthquake intensity, structural slenderness ratio, ratio of foundation mass to structural mass, foundation flexibility and p-δ effects on the response of uplifting structures is also investigated.  相似文献   

Spatio-temporal distribution and characteristics of PAHs in sediments from Masan Bay, Korea   总被引：8，自引：0，他引：8  

Yim UH  Hong SH  Shim WJ  Oh JR  Chang M 《Marine pollution bulletin》2005,50(3):319-326

The distribution of polycyclic aromatic hydrocarbons (PAHs) has been investigated in the surface and core sediments from Masan Bay, Korea. Total PAHs in the surface sediments ranged from 207 to 2670 ng/g dry weight with a mean value of 680 ng/g. Qualitative similarity and quantitative difference between inner and outer bay indicate that the main sources of PAHs are located in the inner bay and outer bay is also affected by the same sources. Vertical distribution of PAHs revealed that three distinctive stages could be differentiated with the help of PCA analysis. The highest concentration (industrialization stage) appeared between late 1950s and 1980, which was 10 years later than other developed countries. A strong pyrolytic source fingerprint has been detected with slight influence of petrogenic sources, and diagenetic PAH, perylene also contributed. Total organic carbon normalized PAHs (sum of 13 PAHs, 8.85-88.0 microg/g OC) were under the threshold effects concentration (TEC, 290 microg/g OC).  相似文献   

Assessment of butyl- and phenyltin pollution in the coastal environment of Korea using mussels and oysters     

Shim WJ  Hong SH  Kim NS  Yim UH  Li D  Oh JR 《Marine pollution bulletin》2005,51(8-12):922-931

Butyl- and phenyltin residues in bivalves were quantified around the coast of Korean peninsula in 1995–1998 and 2001. Butyltin compounds were detected at all the sites surveyed, whereas phenyltins were detected at 41 out of 67 sites in 1995–1998. Tributyltin (TBT) concentrations in bivalves ranged 48–2800 ng Sn/g on dry weight basis. Triphenyltin (TPT) concentrations ranged <3–1820. The mean TPT concentration was 3.5 times less than that of TBT. Spatial distribution of TBT was closely related to boating and dry-docking activities. TPT concentration in bivalves showed significant correlation with TBT. Concentrations of TBT in bivalves, 2001 are not significantly changed compared to those in 1995–1998. However, TPT concentrations in bivalves steeply decreased in 2001. High concentration of TBT and lesser extent TPT and their nation-wide distribution indicate that organotins are one of major organic pollutants in the marine environment of Korea.  相似文献   

Experimental and numerical investigations of tethered spar and sphere buoys in irregular waves   总被引：1，自引：0，他引：1  

E. B. Carpenter  J. W. Leonard  S. C. S. Yim 《Ocean Engineering》1995,22(8)

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A Study of Bispectra in Relation to the Adequacy of Wave Spectral Model     

Yi-Yu Kuo  Chung-Ching Chien John Y. Yim Professor 《中国海洋工程》1997,(2)

In this paper.the characteristics of laboratory wind waves under various wind speeds and wat-er depths are studied.It is found that either the real or the imaginary part of the bispectrum can be relatedto the asymmetry of the wave profile,and the bicoherence is related to the ratio of nonlinear to linear wavecomponent.Occasionally,these two categories of nonlinear index lead to opposite inferences,because eachof them has its own significance and functions.The applicability of linear wave spectral model in oceanwaves becomes questionable only when strong nonlinearity is indicated by both of these two indexes.Thelinear spectral representation of wave fields does not necessarily become inadequate as water depth de-creases,and its appropriateness can be examined through the characteristics of the bispectrum.  相似文献   

A Comparative Study of the Statistical Distributions of Wave Heights     

JohnZ.Yin 《中国海洋工程》1997,(3)

Distribution of wave heights and surface elevations of wind-driven waves are studied.Recordsof surface elevations obtained from both field observations and laboratory measurements are analyzed.Wave heights can be approximated by normal,two-parameter Weibull,and/or Rayleigh distribution.However,while the first two models may have almost equal probabilities to fit measured data quite satis-factorily,the Rayleigh distribution does not appear to be a good model for the majority of the cases stu-died.Surface elevations from field data are well described by the Gaussian model,but as with increasingwind speeds,water surface in a wind-wave flume deviates from normality,and the Edgeworth's form ofthe type A Gram-Charlier series is then applied.  相似文献   

Wave height forecasting by the transfer function model     

Ping Chun Ho  John Z. Yim 《Ocean Engineering》2006,33(8-9):1230-1248

Three completing methods were introduced in this paper. The data were completed from 1983 to 1988 at the KL and PTC stations. The completed data were called original data. The completing methods were the transfer function with fixed-parameters then built the Transfer Function (TF) model between the two stations. The TF model was used to estimate the wave data of the future. The difference of the estimated data and the original data were conferred in this paper. Two types of forecasting differences were discussed here: (1) the input data year increases from 1 to 6 years, and the difference of the estimated data and the original data were then compared. (2) Use one-year data as the input series to forecast the data of the next five years, and then compare the differences of the estimated data and the original data. After comparing the differences we can know the results. The mean value and the standard deviation of the differences decrease and go more stable as the quantity of the input data year increases. The mean value and the standard deviation of the differences increase and go more unstable as the quantity of the forecasted data year increases. This model can be used to forecast the wave data.  相似文献   

Implication of salt marsh foraminiferal assemblages in Suncheon Bay,South Korea     

Da Un Jeong  Yeon Gyu Lee  Sora Kang  Shin Kim  Jung Sick Lee 《Ocean Science Journal》2016,51(1):137-150

Analyses of the compositions of benthic foraminifera and sediment, observations of tidal level and salinity, and a geographic survey of the tidal salt marsh in Suncheon Bay were conducted to examine the vertical distribution of foraminifera and evaluate their potential use for sea level studies. The salt marsh is composed mainly of fine-grained silty clay sediment and its salinity is below approximately 11 psu. The tidal current flows in the southwest-tonortheast direction with an average velocity of 26.57 cm/s. A total of 33 species of foraminifera (17 agglutinated and 16 calcareoushyaline) belonging to 24 genera was identified. The species diversity (1.1 on average) was relatively low. Dominant species were Ammonia beccarii, Miliammina fusca, Haplophragmoides wilberti, and Jadammina macrescens. Calcareous foraminifera (29.5%) were dominantly represented by the Ammonia beccarii assemblage, which characterized the region between mean tide level and mean low high water (MLHW). Agglutinated species (70.5%) were represented mostly by Miliammina fusca, Miliammina fusca-Haplophragmoides wilberti, and Haplophragmoides wilberti assemblages, which characterized the MLHW–mean high water (MHW), MHW–mean highest high water (MHHW), and MHHW–Approx. highest high water tide levels, respectively. In particular, the Haplophragmoides wilberti assemblage is believed to represent the highest elevation zone of foraminifera in the salt marshes of Suncheon Bay and is considered to be a reliable indicator of sea level as a result of its narrow vertical range.  相似文献   

Assessment of tributyltin contamination in a shipyard area using a mussel transplantation approach     

Kim NS  Shim WJ  Yim UH  Ha SY  Park PS 《Marine pollution bulletin》2008,57(6-12):883-888

Mussels (Mytilus galloprovincialis) were transplanted to seven stations around a large shipyard for 126 days to evaluate tributyltin (TBT) contamination. Although the application of TBT-based paints to ships is totally banned in Korea, butyltin compounds were found to accumulate in mussels following transplantation. Concentrations of TBT and total butyltins in transplanted mussels near the shipyard were in the range of 40-350 ng Sn/g and 74-530 ng Sn/g on a dry weight basis, respectively. Obviously, low TBT concentrations (6.0-53 ng Sn/gdw) were determined in mussels at four stations outside the shipyard. A negative gradient of TBT concentrations and TBT portion to total butyltin concentrations were found in both the surface water and transplanted mussels according to distance from the shipyard. In addition, TBT concentrations in surface water and transplanted mussels showed significant correlation (r(2) = 0.71; p < 0.001). These results indicate that the shipyard still releases fresh TBT into surrounding waters even after TBT regulation in Korea, and mussel transplantation is useful in evaluating TBT contamination in shipyard area.  相似文献