超声辐射对牟氏角毛藻的生物效应研究   总被引：6，自引：0，他引：6  

李文权  张元标  陈清花  王清池 《海洋科学》2001,25(10):39-42

设计了一个超声频率，超声功率和辐射时间3因素4水平的正交实验，研究超声辐射对牟氏角毛藻的生物效应。实验结果表明，超声频率对牟氏角毛藻的生物效应显著，而超声功率的辐射时间的影响相对较小，在正交实验所确定的最佳超声辐射条件下，牟氏角毛藻生长速率常数最高可达0．348d^-1，是对照组的1．78倍，并脂肪酸不饱和度最高可达68．4％，比对照组提高5．2％，主要不饱和脂肪酸的百分含量均可得到不同程度的提高。  相似文献   

具有内波特性的渤海南部次重力波     

范植松  高郭平  尹训强  范宇  吴玮 《海洋学报》2003,25(5):136-140

次重力波(infragravity waves)是频率范围介于局地平均Brunt-V¾is¾l¾频率和0.05Hz(涌浪频率)之间的一种海洋波动,其能量在深水大洋中一般甚低,但在浅海中却很强.该波动的研究对于浅海海洋内部混合、近岸海洋工程、海洋生态学、海洋沉积学及军事海洋学均有重要的意义.Munk[1]很早就开始研究这类波动,然而主要由于观测技术的限制,对于该类波动的动力学机制的研究进展迟缓.  相似文献   

辽东湾地区下第三系地震速度—岩性预测模型研究   总被引：9，自引：1，他引：9  

刘震  高先志 《海洋地质与第四纪地质》1993,13(4):25-34

地震速度－岩性预测模型由四个子模型组成：即（１）砂泥岩压实模型；（２）地震层速度转换模型；（３）速度校正模型；（４）砂岩指数转换模型。辽东湾地区的实际资料证明，上述四个子模型不但决定了岩性预测的具体方法，而且严格控制岩性预测的精度。  相似文献   

Wave Defending Effects of V-Type Bottom-Mounted Breakwaters     

缪国平程建生  龙云祥王景全 《中国海洋工程》2005,19(2):195-204

An analytical method is developed for the study of the wave defending effects of the V-type bottom-mounted breakwater. The breakwater is assumed to be rigid, thin, impermeable and vertically located in water of constant depth. The fluid domain is divided into three sub-regions by an imaginary interface. The velocity potential in each region is expanded by eigenfunctions. By satisfying the corresponding boundary conditions and matching conditions in and between sub-regions, a set of hnear algebraic equations can be obtained to determine the unknown coetfficients for the eigenfunction expansions for each sub-region. The accuracy of the present model is verified by a comparison with existing results for the case of an isolated breakwater. Numerical results, in the form of contour maps of the relative wave amplitude around the breakwater, are presented for a range of wave and breakwater parameters. The results show that the V-type bottommounted breakwater is generally effective in defending against waves. In general, the wave height in the protected area is about 20-50 percent of the incident wave height.  相似文献   

Air-Sea Gas Transfer Velocity in Stormy Winter Estimated from Radon Deficiency     

Hitoshi Kawabata  Hisashi Narita  Koh Harada  Shizuo Tsunogai  Masashi Kusakabe 《Journal of Oceanography》2003,59(5):651-661

Thirteen vertical profiles of ²²⁶Ra and ²²²Rn in the near-surface water were obtained in the western North Pacific in winter, and the gas transfer velocities across the air-sea interface were estimated. The transfer velocities found by applying a steady state model varied widely from 2.1 to 30.2 m day⁻¹ with a mean of 9.4 m day⁻¹. The mean value is almost 5 times higher than that in summer in other oceans, and the maximum value is a record high for world oceans. This is partly due to the inadequacy of the steady state model, which overestimates when stronger winds blow in more recent days than the ²²²Rn half-life of about 4 days. In fact, a strong low pressure zone passed through the station about 2 days earlier, which was one of the low pressure zones that with a period of develop once a week or so in the northwestern North Pacific in winter. Instead of steady-state removal, if half of the radon removal occurred sporadically every 7 days, and the last removal took place two days before the observation, the transfer velocity would be 26 m day⁻¹. Our mean transfer velocity, which is less than 20% different from the steady state value including both overestimated and underestimated values, 9.4 ± 4.8 m day⁻¹, seems to represent the mean state of this region in winter. This suggests that the gas exchange fluxes under extremely rough conditions in the open ocean are larger than those estimated by using a transfer velocity equation with a linear or quadratic relationship with wind speed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Experimental activities that intentionally perturb the marine environment: Implications for the marine environmental protection and marine scientific research provisions of the 1982 United Nations Convention on the Law of the Sea     

Philomène A. Verlaan 《Marine Policy》2007

The global community's ability to assess the environmental effects of marine scientific research (MSR) as required by the 1982 United Nations Convention on the Law of the Sea's (UNCLOS) marine environment provisions (MEP) is limited, as shown by experimental activities that intentionally manipulate the marine environment. Such work enhances knowledge of the ocean, but it may also have significant environmental effects. This growing use of the ocean as a laboratory has global scientific, environmental, legal and policy implications. Examined here is the relationship between the MSR and the MEP provisions of UNCLOS. International, science-driven guidelines are proposed.  相似文献   

Correction method for full-depth current velocity with lowered acoustic Doppler current profiler (LADCP)   总被引：1，自引：0，他引：1  

Kanae Komaki  Masaki Kawabe 《Journal of Oceanography》2007,63(6):995-1007

A new method is presented to process and correct full-depth current velocity data obtained from a lowered acoustic Doppler current profiler (LADCP). The analysis shows that, except near the surface, the echo intensity of a reflected sound pulse is closely correlated with the magnitude of the difference in vertical shear of velocity between downcast and upcast, indicating an error in velocity shear. The present method features the use of echo intensity for the correction of velocity shear. The correction values are determined as to fit LADCP velocity to shipboard ADCP (SADCP) and LADCP bottom-tracked velocities. The method is as follows. Initially, a profile of velocity relative to the sea surface is obtained by integrating vertical shears of velocity after low-quality data are rejected. Second, the relative velocity is fitted to the velocity at 100–800 dbar measured by SADCP to obtain an “absolute” velocity profile. Third, the velocity shear is corrected using the relationship between the errors in velocity shears and echo intensity, in order to adjust the velocity at sea bottom to the bottom-tracked velocity measured by LADCP. Finally, the velocity profile is obtained from the SADCP-fitted velocity at depths less than 800 dbar and the corrected velocity shear at depths greater than 800 dbar. This method is valid for a full-depth LADCP cast throughout which the echo intensity is relatively high (greater than 75 dB in the present analysis). Although the processed velocity may include errors of 1–2 cm s⁻¹, this method produced qualitatively good current structures in the Northeast Pacific Basin that were consistent with the deep current structures inferred from silicate distribution, and the averaged velocities were significantly different from those calculated by the Visbeck (2002) method.  相似文献   

中国海洋交通运输业碳排放效率测度及影响因素分析     

董梦如  韩增林  郭建科 《海洋通报》2020,39(2):169-177

海洋交通运输业碳排放研究对制定行之有效的低碳海洋交通政策具有重要意义。本文首先对2006—2015年中国沿海11个省(区、市)的海洋交通运输业碳排放量进行估算,然后运用超效率SBM模型对碳排放效率进行测度,最后运用Tobit模型探究碳排放效率的影响因素。结果表明:①中国海洋交通运输业碳排放效率整体上处于低效率状态,且各省(区、市)间差异明显,但差异正在逐渐缩小。②2006—2015年沿海各省(区、市)市海洋交通运输业碳排放效率变动呈现出“M”形波动上升趋势。③将各省(区、市)海洋交通运输业碳排放效率水平划分为不同类型,其中上海和天津属于高效率型,河北属于中效率型,其余省(区、市)市属于低效率型。④货运距离和能源结构对海洋交通运输业碳排放效率具有显著的正向作用,而能源强度对其具有显著的负向作用。  相似文献   

结构损伤初步定位的简便方法     

孟海平  杨永春  杨风艳 《中国海洋大学学报(自然科学版)》2006,36(5):785-789

提出将基于动态特性的检测方法与局部物理检测手段相结合的探伤思路。利用动力学方法进行实时监测及损伤区域的粗略定位,再由物理探测方法实现损伤程度和位置的精确判断,从而降低对动态检测方法的精度要求。此外,文中尝试直接由结构的动力响应信号构建能量指标识别结构损伤的方法,不需要进行模态参数识别,算法简单,有望应用于海洋平台、高层建筑等可简化为串联多自由度体系的结构的实时监测和损伤初步定位。  相似文献   

Industry participation in stock assessment: the New Zealand SNA1 snapper (Pagrus auratus) fishery     

Mark N. Maunder  Paul J. Starr   《Marine Policy》2002,26(6)

We describe industry funded contributions to the assessment of the SNA1 snapper (Pagrus auratus) fishery during the 1990s and discuss the advantages and disadvantages of industry funded research. We also provide background on the history of fisheries management in New Zealand, on the current assessment and management processes, and on the SNA1 snapper fishery. In the SNA1 fishery, the contributions of industry and the cooperation with Government scientists has resulted in high quality assessments. In our opinion, the advantages of industry funded research out weigh the disadvantages and suggest that industry funded assessments are highly desirable and should be an integral part of any management system.  相似文献