象山港海域分区评价方法研究          下载免费PDF全文

金余娣  叶林安  刘莲  章紫宁  鲁水 《海洋开发与管理》2020,37(7):45-48

文章根据2011-2018年在象山港海域调查的象山港水文、水团、水环境、沉积物环境、生物生态等调查数据，将象山港海域划分为若干个具有不同生态变化特征的区域，研究象山港海域内的空间异质性，以便剖析各区域环境的问题。研究发现：象山港水交换特征、水团分布、水环境、沉积环境和生物生态特征将象山港划分为A、B、C、D、E 5个区评价较为合理。该方法可以有效并合理地对象山港海域做出评价，并为相关海洋科学工作者和管理者提供科学依据。  相似文献   

First Multi‐Isotopic (Pb‐Nd‐Sr‐Zn‐Cu‐Fe) Characterisation of Dust Reference Materials (ATD and BCR‐723): A Multi‐Column Chromatographic Method Optimised to Trace Mineral and Anthropogenic Dust Sources     

Aubry Vanderstraeten  Steeve Bonneville  Stefania Gili  Jeroen de Jong  Wendy Debouge  Philippe Claeys  Nadine Mattielli 《Geostandards and Geoanalytical Research》2020,44(2):307-329

Atmospheric dust is an integral component of the Earth system with major implications for the climate, biosphere and public health. In this context, identifying and quantifying the provenance and the processes generating the various types of dust found in the atmosphere is paramount. Isotopic signatures of Pb, Nd, Sr, Zn, Cu and Fe are commonly used as sensitive geochemical tracers. However, their combined use is limited by the lack of (a) a dedicated chromatographic protocol to separate the six elements of interest for low‐mass samples and (b) specific reference materials for dust. Indeed, our work shows that USGS rock reference materials BHVO‐2, AGV‐2 and G‐2 are not applicable as substitute reference materials for dust. We characterised the isotopic signatures of these six elements in dust reference materials ATD and BCR‐723, representatives of natural and urban environments, respectively. To achieve this, we developed a specific procedure for dust, applicable in the 4–25 mg mass range, to separate the six elements using a multi‐column ion‐exchange chromatographic method and MC‐ICP‐MS measurements.  相似文献   

渤海自由生活海洋线虫两个新纪录种     

赵丽萍  乔春艳  陆洋  孙静 《海洋与湖沼》2020,51(1):212-217

在对渤海滨州贝壳堤岛的自由生活海洋线虫进行分类和多样性研究中,发现2个我国新纪录种并进行了描述。其中,澳洲深咽线虫Bathylaimus australis Cobb,1894主要特征为:头刚毛长约20μm,分为4节,顶端膨大;前口腔大,无齿,后口腔小,具小齿;化感器双环形,位于口腔中部位置;交接刺细长,稍向腹面弯曲,近端膨大呈头状,长32-37μm;引带宽大,肾形,长36-40μm,末端角质化,渐尖。古氏努朵拉线虫Nudora gourbaultae Vincx,1989主要特征为:体表具12列纵向排列的V型装饰;第二体环较宽,头刚毛11-15μm(为头颈的67%-81%);化感器圆形,直径4-6μm(为相应体径的29%-38%),位于第二体环上;具双咽球;交接刺细长,弯曲呈S型,长为肛径的1.3-1.5倍;引带等于或长于交接刺,镰刀型,无肛前辅器。  相似文献   

守初心耕海探洋七十载担使命披风踏浪砥砺行——中国科学院海洋研究所70年发展纪实   总被引：1，自引：0，他引：1  

王凡  孙松 《海洋与湖沼》2020,51(4):664-672

中国科学院海洋研究所是新中国第一个专门从事海洋科学研究的国立科研机构,她的70年光辉历程是我国海洋科技事业从无到有、从弱到强的发展缩影,是新中国海洋科学调查研究自主创新发展历程的真实写照。本文简要介绍中国科学院海洋研究所的主要发展历程,回顾70年来取得的主要科技成就,并围绕新形势下建设海洋大科学研究中心等改革发展举措,讨论和展望研究所的未来发展。  相似文献   

舟山群岛外海域鱼类数量分布与环境因子的关系     

于南京  俞存根  许永久  陈立红  许恒涛  王慧君  张佩怡  刘坤 《海洋学报》2020,42(10):80-91

根据2018年4月（春季）和10月（秋季）在舟山群岛外海域进行的渔业资源调查资料，分析了鱼类的种类组成、数量分布和优势种，并用典范对应分析方法分析了其与水文环境之间的关系。结果表明，舟山群岛外海域鱼类有106种，隶属于12目47科80属，春、秋季鱼类质量密度分别为210.50 kg/km2和829.06 kg/km2，尾数密度分别为8.08×103 ind/km2和165.94×103 ind/km2。春季鱼类资源密度在调查海域的西北部较高，东部较低，而秋季鱼类资源密度在东部海域较高，西北部海域较低。两个季节的鱼类优势种更替明显，春季优势种为黄鮟鱇（Lophius litulon）、日本红娘鱼（Lepidotrigla japonica）、细条天竺鲷（Apogon lineatus），秋季为细条天竺鲷、日本发光鲷（Acropom japonicum）。鱼类种数呈现显著的季节和空间变化，但是都以西部以及西北部靠近近岸岛屿的海域种类数较高，大部分鱼类栖息在50～80 m水深海域。典范对应分析结果表明，表层温度、底层温度、表层盐度是影响调查海域鱼类种类组成和数量分布的主要环境因子。  相似文献   

无人船运动控制方法综述   总被引：1，自引：1，他引：0  

裴志远  戴永寿  李立刚  金久才  邵峰 《海洋科学》2020,44(3):153-162

为实现无人船海上自主作业,无人船运动控制的快速性、准确性以及鲁棒性亟待提高。首先从全驱动控制和欠驱动控制角度,分别概括了国内外无人船航向控制、航速控制、轨迹跟踪控制以及路径跟踪控制的主流控制方法。其次,归纳总结了处理海洋环境不确定扰动的研究进展,包括扰动的建模和消除、抑制扰动的主流方法。最后,总结了无人船运动控制现状与存在的问题,并从工程应用和理论研究两个角度对未来的研究方向进行了展望。  相似文献   

大型射电望远镜主反射面调整方法研究          下载免费PDF全文

孙正雄  王锦清  虞林峰  张志斌  王广利 《天文学报》2024,65(2):15

随着毫米波天文学和空间通信的重要性日益提高, 对天线性能提出了越来越高的要求, 而天线性能往往受到其反射器表面精度的限制. 微波全息技术是一种快速有效的检测反射面天线表面轮廓的测量技术. 通过微波全息测量得到天线口径场, 计算天马65m射电望远镜反射面与理想抛物面的偏差. 天马65m射电望远镜的主反射面板是放射状的, 有14圈. 面板的每个角都固定在面板下方促动器的螺栓上进行上下移动, 且相邻面板交点处的拐角共用一个促动器. 采用平面拟合的方法可以计算各块面板拐角处的调整值, 但是同一个促动器会得到4个不同的调整量. 通过平面拟合, 同时以天线照明函数为权重的平差计算方法得到相邻面板拐角的一个平差值, 即天马65m射电望远镜1104个促动器的最佳调整值. 通过多次调整和新算法的应用, 天马65m射电望远镜反射面的面形精度逐渐提高到了0.24mm.  相似文献   

A Sensitivity Study of Arctic Ice-Ocean Heat Exchange to the Three-Equation Boundary Condition Parametrization in CICE6     

Lei YU  Jiping LIU  Yongqi GAO  Qi SHU 《大气科学进展》2022,39(9):1398-1416

In this study, we perform a stand-alone sensitivity study using the Los Alamos Sea ice model version 6 (CICE6) to investigate the model sensitivity to two Ice-Ocean (IO) boundary condition approaches. One is the two-equation approach that treats the freezing temperature as a function of the ocean mixed layer (ML) salinity, using two equations to parametrize the IO heat exchanges. Another approach uses the salinity of the IO interface to define the actual freezing temperature, so an equation describing the salt flux at the IO interface is added to the two-equation approach, forming the so-called three-equation approach. We focus on the impact of the three-equation boundary condition on the IO heat exchange and associated basal melt/growth of the sea ice in the Arctic Ocean. Compared with the two-equation simulation, our three-equation simulation shows a reduced oceanic turbulent heat flux, weakened basal melt, increased ice thickness, and reduced sea surface temperature (SST) in the Arctic. These impacts occur mainly at the ice edge regions and manifest themselves in summer. Furthermore, in August, we observed a downward turbulent heat flux from the ice to the ocean ML in two of our three-equation sensitivity runs with a constant heat transfer coefficient (0.006), which caused heat divergence and congelation at the ice bottom. Additionally, the influence of different combinations of heat/salt transfer coefficients and thermal conductivity in the three-equation approach on the model simulated results is assessed. The results presented in this study can provide insight into sea ice model sensitivity to the three-equation IO boundary condition for coupling the CICE6 to climate models.  相似文献   

Trans-Arctic shipping routes expanding faster than the model projections     

《Global Environmental Change》2022

Rapid declines in Arctic sea ice coverage over the past four decades have increased the commercial feasibility of trans-Arctic routes. However, the historical changes in navigability of trans-Arctic routes remain unclear, and projections by global circulation models (GCMs) contain large uncertainties since they cannot simulate long-term Arctic sea ice changes. In this study, we determined the changes in trans-Arctic routes from 1979 to 2019 by combining two harmonized high-quality daily sea ice products. We found that the trans-Arctic routes are becoming navigable much faster than projected by the GCMs. The navigation season for open water (OW) vessels along the Northeast Passage (NEP) has lengthened from occasionally navigable in the 1980 s to 92 ± 15 days in the 2010 s. In contrast, previous GCM projections have suggested that navigability would not be achieved until the mid-21st century. The 90-day safety shipping area for OW vessels expanded by 35% during 1979–2018, reaching 8.28 million km² in 2018, indicating an increasing rate of 0.08 ± 0.01 million km² per year. The shortest trans-Arctic routes were also shifted further north than the model projections. Regular ships have been able to safely travel north along the islands in the NEP and transit through the M’Clure Strait in the Canadian Arctic Archipelago during the 2010 s, while previous studies have projected that this would not be feasible until the mid-21st century. We also found that the improved navigability of trans-Arctic routes enables commercial ships to transport approximately 33–66% (at the same load factor) more goods from East Asia to Europe during the Arctic shipping season than by the traditional Suez Canal route. These findings highlight the need for aggressive actions to develop mandatory rules that promote navigation safety and strengthen environmental protection in the Arctic.  相似文献   

Environmental regulation and innovation: Evidence from China     

《Global Environmental Change》2022

The relevance of analyzing effects of environmental regulation on innovation cannot be overemphasized. In this paper, we first develop a theoretical model to predict how command-and-control environmental regulation affects innovation, and then we derive its channels. Using the difference-in-difference-in-differences strategy and a comprehensive dataset at city-industry-year level of manufacturing sectors in China, we found that the more stringent environmental regulations that are faced by cities, measured by the reduction targets of chemical oxygen demand (COD) and sulfur dioxide (SO₂) during the eleventh Five-Year Plan, are negatively associated with innovation. Thus, the evidence contradicts the Porter Hypothesis. On average, a one standard deviation increase in the reduction targets of COD (SO₂) is associated with a 0.023 (0.016) standard deviation decrease in the innovation index. We controlled carefully for various potential confounders, and the results were supported by robustness and falsification checks. There exists an evident heterogeneity effect across regions and industries with different pollution intensities. The channel analysis shows that stricter environmental regulation also accounts for a sharp decline in labor demand, firm entry, and inbound foreign direct investment. Our findings are also robust to alternative measures for innovation and environmental regulation.  相似文献