Hydrodynamic and water column properties at six stations associated with mussel farming in Pelorus sound, 1984–85     

M. M. Gibbs  M. R. James  S. E. Pickmere  P. H. Woods  B. S. Shakespeare  R. W. Hickman 《新西兰海洋与淡水研究杂志》2013,47(3):239-254

Mussel farming places a benthic organism in a pelagic environment; it is therefore important to understand the driving force that transports the food to the mussels. The hydrodynamic regimes in the sidearms and embayments in Pelorus Sound are dominated by the lunar tide, and a net estuarine circulation in the main channel flowing inwards along the bottom and outwards along the top. Salinity gradients extend throughout the sound from the river inflows, with strongest density stratification in the sidearms and embayments: nearest the head of the sound. There, the water column is separated at the pycnocline into upper and lower layers which tend to move in different directions or at different velocities. Local circulation patterns modify tidal flushing patterns, producing extended residence times in some embayments, whereas other embayments off the side of the main channel tend to be flushed more rapidly by through‐flow water and have shorter residence times than would otherwise be expected. The changing inflow of fresh water modifies the local hydraulic regimes in the inner sounds, especially during flood conditions.  相似文献   

Vertical Distributions of Larvae of the Clam <Emphasis Type="Italic">Ruditapes philippinarum</Emphasis> and the Striped Horse Mussel <Emphasis Type="Italic">Musculista senhousia</Emphasis> in Eastern Ariake Bay,Southern Japan     

Ryo?Ishii  Hideo?SekiguchiEmail author  Yasunari?Jinnai 《Journal of Oceanography》2005,61(5):973-978

We have examined the vertical distributions of planktonic bivalve larvae, particularly the clam Ruditapes philippinarum and the mussel Musculista senhousia which are common and abundant on tidal flats of eastern Ariake Bay, southern Japan. Submersible pumping gear was used to take samples at 2 stations every 2 hours during the spring tide over a whole tidal cycle and/or through daytime and nighttime. Water samples were pumped up from 3 to 5 depths from the surface to sea bottom. Regardless of tidal cycles, D-shaped larvae were concentrated near the surface, while umbo larvae were found at the surface to intermediate depths. On average, these larval densities were significantly higher at the station close to the shore than the offshore station, with no significant difference between daytime and nighttime and between flood and ebb tides at each station. The velocity and direction of water movement at both stations revealed remarkable difference between the surface and bottom waters. The larvae at the surface may quickly disperse and be transported elsewhere, while those in water close to the sea bottom may tend to be retained.  相似文献   

Life history, distribution, and size structure of Pacific capelin in Prince William Sound and the northern Gulf of Alaska   总被引：2，自引：2，他引：2  

Brown  Evelyn D. 《ICES Journal of Marine Science》2002,59(5):983-996

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Estimating turbulent dissipation rates from acoustic backscatter     

Tetjana Ross  Rolf Lueck 《Deep Sea Research Part I: Oceanographic Research Papers》2005,52(12):2353-2365

Recent work has suggested the possibility of using high-frequency (10 kHz to 1 MHz) acoustics to remotely sense turbulent microstructure in the ocean. Once developed, this technique will provide a powerful tool for examining the spatial and temporal distributions of ocean mixing in a way not possible using traditional microstructure methods. In this paper turbulent dissipation rates are estimated through an inversion of 307 kHz acoustic scattering data collected in the lee of a sill in Knight Inlet, British Columbia. These data have been shown previously to be strongly correlated with temperature and shear microstructure measurements. Here we show that inversion methods can be used to get turbulent dissipation rates from acoustic backscatter, provided that independent measurements of temperature and salinity stratification are available. The temperature–salinity characteristics of the environment, however, can place limitations on the inversion technique. The strong negative salinity gradient in Knight Inlet decreases the slope of the functional relationship between dissipation rate and scattering cross-section for high dissipation rates and increases the uncertainty of the inversion. This limitation on the inversion technique is not an issue throughout most of the world's oceans (where dT/dS>0) and, in places where it could be a problem, the limitation can be overcome by using multi-frequency techniques.  相似文献   

Earthquake-induced residual deformation of Ariake clay deposits with leaching   总被引：1，自引：0，他引：1  

H. Nagase  K. Shimizu  A. Hiro-oka  Y. Tanoue  Y. Saitoh 《Soil Dynamics and Earthquake Engineering》2006,26(2-4):209-220

It is widely known that the sensitivity ratio of Ariake marine clay increases, if the clay is leached. Therefore, it is assumed that the mechanical properties of such clay considerably change and the shear strength decreases, if it is subjected to a cyclic load as a disturbance force, like earthquakes. In the present study, dynamic deformation and strength tests, as well as consolidation tests were conducted on Ariake clay that had leached. Static shear tests were also carried out on the clay after it had been subjected to a cyclic load. The stability of man-made earth structures on Ariake clay deposits that had leached during earthquakes was investigated. Undisturbed samples of the clay sedimented in the sea area were used in all the tests. Furthermore, an earthquake-induced residual deformation analysis was also conducted on the basis of the test results described above. Consequently, the following behaviors were observed in the study. (1) When Ariake marine clay was leached, the dynamic strength decreased and the shear modulus after subjecting it to a cyclic load remarkably decreased. (2) The effect of the leaching on the behavior of Ariake clay deposits was considerable during earthquakes.  相似文献   

Asperity distribution of the 1964 Great Alaska earthquake and its relation to subsequent seismicity in the region     

S. Santini  M. Dragoni  G. Spada 《Tectonophysics》2003,367(3-4):219-233

The 1964 Alaska earthquake was the second largest seismic events in the 20th century. The aim of this work is the use of surface deformation data to determine asperity and slip distributions on the fault plane of the Alaska earthquake: these distributions are calculated by a Monte Carlo method. To this aim, we decompose the fault plane in a large number of small square asperity units with a side of 25 km; this allows us to obtain plane surfaces with an irregular shape. In the first stage, each asperity unit is allowed to slip a constant amount or not to slip at all, providing the geometry of the dislocation surface that best reproduces the observed displacements. To this purpose, a large number of slip distributions have been tried by the use of the Monte Carlo method. The slip amplitude is the same for all the asperities and is equal to the average fault slip inferred from the seismic moment. In the second stage, we evaluate the slip distribution in the dislocation area determined by the Monte Carlo inversion: in this case, we allow unit cells to undergo different values of slip in order to refine the initial dislocation model. The results confirm the previous finding that the slip distribution of the great Alaska earthquake was essentially made of two dislocation areas with a higher slip, the Prince William Sound and the Kodiak asperities. Analysis of the post-1964 seismicity in the rupture region shows a strong correlation between the larger earthquakes (M_w≥6) and the distribution of locked asperities following the 1964 event, which can be considered as an independent test of the validity of the model. We do not find slip values higher than 25 m for any of the patches, and we determine two separate high-slip zones: one correspondent to the Prince William Sound asperity, and one (18 m slip) to the Kodiak asperity. The slip distribution connected with the 1964 shock appears to be consistent with the following seismicity in the region.  相似文献   

声控指挥图形显示智能系统的研究     

刘光运 《测绘学院学报》1991,(2)

本文在分析声控产生态势图必要性的基础上,提出了利用计算机及其外围设备和语音识别器构成声控指挥图形显示智能系统的设计思想、功能、数据流程和结构。  相似文献   

Model of the Long Island Sound outflow: Comparison with year-long HF radar and Doppler current observations     

Jenq-Chi Mau  Dong-Ping Wang  David S. Ullman  Daniel L. Codiga 《Continental Shelf Research》2008

A three-dimensional primitive-equation model is used to simulate the Long Island Sound (LIS) outflow for a 1-year (2001) period. The model domain includes LIS and New York Bight (NYB). Tidal and wind forcing are included, and seasonal salinity and temperature variations are assimilated. The model results are validated with the HF radar, moored acoustic Doppler current profiler (ADCP), and ferry-based ADCP observations. The agreement between simulated and observed flow patterns generally is very good. The difference in seasonal mean currents between the model and moored ADCP is about 0.01 m/s; the correlation of dominant velocity fluctuations between the model and HF radar is 0.83; and the difference in mean LIS transport between the model and shipboard ADCP is about 5%. However, the model predicts a prominent tidally generated headland eddy not supported by the HF radar observation. The model sensitivity study indicates that the tides, winds, and ambient coastal front all have important impact on the buoyant outflow. The tides and winds cause stronger vertical mixing, which reduces the surface plume strength. The ambient coastal front, on the other hand, tends to enhance the plume.  相似文献   

辽宁省国土资源沙盘模型制作及特点   总被引：2，自引：1，他引：1  

张衍明  庞群 《现代测绘》2003,26(3):43-44

本文以辽宁省国土资源沙盘模型为例,详细介绍了现代沙盘模型的制作方法及特点。  相似文献   

Adjustment of benthic fauna following sediment disposal at a site with multiple stressors in Port Valdez, Alaska     

Blanchard AL  Feder HM 《Marine pollution bulletin》2003,46(12):1590-1599

The shallow subtidal macrobenthos at Port Valdez, Alaska, was examined to assess faunal adjustment following disposal of dredged sediments over a three-year period. Prior to sediment disposal, the infauna consisted of a relatively species-rich assemblage dominated by sessile polychaetes and bivalves. Six months after disposal, virtually all taxa present prior to dredging and disposal were rare or absent with opportunistic taxa dominant. Surveys performed 1.5 years after sediment disposal indicated faunal adjustment was in progress; large, sessile polychaetes and bivalves were still present in low numbers after 2.5 years. At one station, increasing organic enrichment by fish-wastes from adjacent processing plants resulted in a shift to a highly disturbed benthic assemblage. The trends in the faunal assemblage suggest that environmental conditions were still in a state of flux 2.5 years after the dredging event.  相似文献