疏浚物倾倒区海水水质级别的模糊综合评价     

刘现明  徐恒振 《海岸工程》1995,14(2):33-37

应用模糊综合评价方法对大连臭水套海域疏浚物预选倾倒区的水质状况进行了评价，得到了有益的结论。  相似文献   

长江口水域双带蛤科一新种     

徐凤山 《海洋与湖沼》1996,27(2):200-202

于１９８５－１９８６年在长江口的底栖生物取样中，采到大量双壳类软体动物标本。鉴定表明，其中一新种，被定名为中华团结蛤Ａｂｒａ ｓｉｍｉｃａ ｓｐ．ｎｏｖ。，属樱蛤超科中的双带科（Ｓｅｍｅｌｉｄａｅ）。模式标本保存于中国科学院海洋研究所。  相似文献   

Remote estimation of surficial seafloor properties through the application Angular Range Analysis to multibeam sonar data   总被引：2，自引：2，他引：2  

Luciano Fonseca  Larry Mayer 《Marine Geophysical Researches》2007,28(2):119-126

The variation of the backscatter strength with the angle of incidence is an intrinsic property of the seafloor, which can be used in methods for acoustic seafloor characterization. Although multibeam sonars acquire backscatter over a wide range of incidence angles, the angular information is normally neglected during standard backscatter processing and mosaicking. An approach called Angular Range Analysis has been developed to preserve the backscatter angular information, and use it for remote estimation of seafloor properties. Angular Range Analysis starts with the beam-by-beam time-series of acoustic backscatter provided by the multibeam sonar and then corrects the backscatter for seafloor slope, beam pattern, time varying and angle varying gains, and area of insonification. Subsequently a series of parameters are calculated from the stacking of consecutive time series over a spatial scale that approximates half of the swath width. Based on these calculated parameters and the inversion of an acoustic backscatter model, we estimate the acoustic impedance and the roughness of the insonified area on the seafloor. In the process of this inversion, the behavior of the model parameters is constrained by established inter-property relationships. The approach has been tested using a 300 kHz Simrad EM3000 multibeam sonar in Little Bay, NH. Impedance estimates are compared to in situ measurements of sound speed. The comparison shows a very good correlation, indicating the potential of this approach for robust seafloor characterization.  相似文献   

4D seismic time-lapse monitoring of an active cold vent,northern Cascadia margin   总被引：1，自引：1，他引：1  

Michael Riedel 《Marine Geophysical Researches》2007,28(4):355-371

Two single-channel seismic (SCS) data sets collected in 2000 and 2005 were used for a four-dimensional (4D) time-lapse analysis of an active cold vent (Bullseye Vent). The data set acquired in 2000 serves as a reference in the applied processing sequence. The 4D processing sequence utilizes time- and phase-matching, gain adjustments and shaping filters to transform the 2005 data set so that it is most comparable to the conditions under which the 2000 data were acquired. The cold vent is characterized by seismic blanking, which is a result of the presence of gas hydrate in the subsurface either within coarser-grained turbidite sands or in fractures, as well as free gas trapped in these fracture systems. The area of blanking was defined using the seismic attributes instantaneous amplitude and similarity. Several areas were identified where blanking was reduced in 2005 relative to 2000. But most of the centre of Bullseye Vent and the area around it were seen to be characterized by intensified blanking in 2005. Tracing these areas of intensified blanking through the three-dimensional (3D) seismic volume defined several apparent new flow pathways that were not seen in the 2000 data, which are interpreted as newly generated fractures/faults for upward fluid migration. Intensified blanking is interpreted as a result of new formation of gas hydrate in the subsurface along new fracture pathways. Areas with reduced blanking may be zones where formerly plugged fractures that had trapped some free gas may have been opened and free gas was liberated.  相似文献   

Phytoplankton biomass and size fractions in surface waters of the Australian sector of the southern ocean     

Wendy Ehnert  C. Peter McRoy 《Journal of Oceanography》2007,63(2):179-187

We collected surface water along the 142nd E meridian from Tasmania to Antarctica in December 1999. We measured temperature, salinity and total chlorophyll a; additionally, we collected suspended particle size fractions and used fluorometric analysis to determine the quantity of chlorophyll a in each of four cell size classes: picoplankton (<3 μm), two nanoplankton fractions (3–10 μm and 10–20 μm) and microplankton (> 20 μm). Changes in temperature and salinity show that we crossed 6 water masses separated by 5 fronts. We found low abundance (<0.2 mg m⁻³) of chlorophyll in all size classes, with the exception of higher values near the continent (0.2 to 0.4 mg m⁻³). Lowest chlorophyll values (<0.1 mg m⁻³) were found in the Polar Frontal Zone (51° to 54°S). Microplankton made up the largest portion of total chlorophyll throughout most of the region. We conclude that biomass of all phytoplankton fractions, especially pico-and nanoplankton, was constrained by limiting factors, most probably iron, throughout the region and that ecosystem dynamics within a zone are not circumpolar but are regionalized within sectors.  相似文献   

Effects of an Artificial Breakwater on the Distributions of Planktonic Microbial Communities     

Young-Ok Kim  Eun Jin Yang  Jung-Hoon Kang  Kyoungsoon Shin  Man Chang  Cheol Soo Myung 《Ocean Science Journal》2007,42(1):9-17

The summer distributions of planktonic microbial communities (heterotrophic and phtosynthetic bacteria, phtosynthetic and heterotrophic nanoflagellates, ciliate plankton, and microphytoplankton) were compared between inner and outer areas of Lake Sihwa, divided by an artificial breakwater, located on the western coast of Korea, in September 2003. The semienclosed, inner area was characterized by hyposaline surface water (<17 psu), and by low concentrations of dissolved oxygen (avg. 0.4 mg L¹) and high concentrations of inorganic nutrients (nitrogenous nutrients >36 μM, phosphate <4 μM) in the bottom layer. Higher densities of heterotrophic bacteria and nanoflagellates also occurred in the inner area than did in the outer area, while microphytoplankton (mainly diatoms) occurred abundantly in the outer area. A tiny tintinnid ciliate, Tintinnopsis nana, bloomed into more than 10⁶ cells L¹ at the surface layer of the inner area, while its abundance was much lower (10³-10⁴ cells L¹) in the outer area of the breakwater. Ciliate abundance was highly correlated with heterotrophic bacteria (r = 0.886, p < 0.001) and heterotrophic flagellates (r = 0.962, p < 0.001), indicating that rich food availability may have led to theT. nana bloom. These results suggest that the breakwater causes the eutrophic environment in artificial lakes with limited flushing of enriched water and develops into abundant bacteria, nanoflagellates, and ciliates.  相似文献   

台湾海峡台风暴潮非线性数值计算   总被引：2，自引：1，他引：2  

吴培木  许永水  李燕初  陈玉霞  陈季良 《海洋学报》1981,3(1):28-43

台湾海峡平均水深不大于50米,台风侵袭频繁.由于台湾岛的“墙壁效应”和台湾海峡的“狭管效应”的影响,台湾海峡的台风暴潮显得较为独特.以前,我们及其他兄弟单位对福建沿海台风暴潮的研究,大多数仅局限于单站的气-水动力相互作用的研究,很少涉及整个海峡.虽说我们也曾作过福建沿岸台风暴潮现场调查,但进行次数有限,了解的也仅是海峡西岸局部地区的情况,它仅能反映台湾海峡台风暴潮的一个侧面,而无法了解整个海峡地区的风暴潮全貌.  相似文献   

打好“桥”牌,顺利实现舟山市由海岛经济向半岛经济的转型          下载免费PDF全文

黄旭 《海洋开发与管理》2005,22(5):80-87

2008年,浙江省舟山市这个千岛城市将成为半岛城市,其海岛经济也将向半岛型经济转变.实现这个经济转型,首先全市上下应提高思想认识,其次三大产业的发展上要有新调整,在主攻海洋经济时,应将长三角和全国作为发展的腹地,凸现半岛在经济发展中的优势,还应处理诸如发展经济与保护资源环境等方面的关系.  相似文献   

悬浮沙激光散斑图像处理的研究     

杜军兰  陈靖齐  于连生  刘海坤  徐雷 《海洋技术学报》2001,20(1):107-111

本文以统计模式识别为基础，阐述了图像处理在悬浮沙粒粒径流量中的实际应用，提出了用图像层析来确定放大系数的方法，提出了测量的准确度。  相似文献   

东太平洋下中新统氧同位素地层与古海洋学意义     

陈宗团  许东禹 《海洋地质与第四纪地质》1993,13(1):85-94

研究取自于东太平洋CC48柱状样的钙质超微化石和底栖有孔虫的氧同位素成分变化的结果表明,该区下中新统至少可分出九个氧同位素地层(期),反映该区在早中新世期间至少经历了4次气温上升和5次下降的古气候变化。南极大陆冰川应是形成于早中新世而不是前人认为的中中新世。在早中新世,南极冰体体积有较大的变化。受古气候变化的影响,在早中新世期间东太平洋水柱热结构或温度梯度有比较大的变化,海平面出现多次上升与下降。  相似文献