大长山岛附近海域流

发布时间：2018-06-16 02:39

本文选题：流场 + N-S方程　；参考：《大连海洋大学》2016年硕士论文

【摘要】：海洋牧场是指在某一海域内,采用一整套规模化的渔业设施和系统化的管理体制,利用自然的海洋生态环境,将人工放流的经济海洋生物聚集起来,进行有计划有目的的海上放养鱼虾贝类的大型人工渔场。其目的在于提高某些经济品种的产量或整个海域的鱼类产量,以确保水产资源稳定和持续的增长;以及利用海洋资源的同时重点保护海洋生态系统,实现可持续生态渔业。本文通过对大长山岛海域海流的观测数据,并采集该地区的7个采样点的营养盐及渔获物数据,进行分析。主要获得以下结论:1.研究不可压缩的粘性流体时,使用N-S方程体定性的描述了流场。使用菲克第二定律将研究区域内的营养盐作为扩散研究物质,定性解答。并描述了该海域中构成浓度梯度的营养盐在非稳态流体中,需要将流体的流速流向和营养盐的浓度大小、浓度梯度方向将被在一起综合考虑分析。2.通过对流场的作图分析,从0.5 m、2.5 m、4.5 m水层流场玫瑰图和Excel雷达图得到东南向流为主流向;从0.5 m水层流向与2.5 m水层流向分析,该海域符合Ekman漂流理论,北半球流向逐渐偏向流向的右侧,俯视方向呈顺时针偏转。3.在不考虑其他外界条件,并假定无边界开阔水域中海水流动方向单一的情况下,营养盐运输的速度矢量是其扩散速度矢量与海流速度矢量的运算结果。并且在实际的海域中,岸边的阻拦效果、海水深浅梯度改变、营养盐浓度时刻的改变致使扩散梯度的变化等,都会使营养盐的运输速度矢量发生变化。4.大长山海域的水体从总氮、总磷两种营养盐的含量变化上看,已受到轻度污染,主要污染物为无机氮、磷酸盐等,但污染情况得到好转;水体富营养化趋势不明显,总体处于贫营养水平,有机污染水平较低。5.营养盐会促使浮游生物繁殖,但是某一个区域的浮游生物的数量多少,除了该区域营养盐的含量多少外,还有海流会迫使浮游生物运动至此增多或离开减少。6.生物多样性评价结果为大长山调查海域的渔获物物种由此前的27种上升到36种,逐渐越来越多的物种栖息说明该海域生息场恢复较好。后续生物多样性指数H’高于以往调查结果,生物多样性指数升高趋势。均匀度指数J’降低,凸显了大长山海域常年渔获物有优势种3种,分别为大泷六线鱼(Hexagrammos otakii)、许氏平泲(Gymnocor ymbus ternetzi)、日本鲟(Charybdis japonica),而其他物种相对比这三个物种,竞争力较小。物种丰度指数D’增加,物种种类上升到36种。结果表明海流将营养盐带入这片海域,使这片海域中的生物得到恢复,持续生息繁衍,物种增加,在该项目研究中得到了一个非常满意的结果。
[Abstract]:Ocean rangeland refers to the use of a set of large-scale fisheries facilities and a systematic management system in a certain sea area, and the use of the natural marine ecological environment to gather artificially released economic marine life. A large artificial fishing ground for purposeful marine stocking of shellfish and shellfish. The aim is to increase the yield of certain economic species or fish in the whole sea area in order to ensure the stable and sustained growth of aquatic resources, and to utilize marine resources while focusing on the protection of marine ecosystem and to achieve sustainable ecological fisheries. In this paper, the data of the ocean current in the Great Changshan Island and the nutrient and catch data of 7 sampling sites in this area are collected and analyzed. The main conclusions are as follows: 1. In the study of incompressible viscous fluid, the flow field is described qualitatively by using N-S equation. Using Fick's second law, the nutrient in the study area is used as diffusion research material, qualitative solution. It is also described that in the unsteady fluid, the flow direction of the fluid and the concentration of the nutrient should be considered in the direction of the concentration gradient. Based on the analysis of the convection field, the main flow direction of the southeasterly current is obtained from the rose chart of the flow field in the water layer of 0.5 m ~ (2.5 m) and the Excel radar chart, and the flow direction is analyzed from the flow direction of the water layer of 0.5 m and 2.5 m, which accords with the Ekman drift theory. The direction of the Northern Hemisphere gradually deviates to the right of the direction, and the direction of the overlooking direction is clockwise deflected. 3. The velocity vector of nutrient transport is the result of calculation of diffusion velocity vector and current velocity vector without considering other external conditions and assuming that the flow direction of seawater in boundless open water is single. And in the actual sea area, the blocking effect of the shore, the change of the depth and shallow gradient of seawater, the change of the diffusion gradient caused by the change of the nutrient concentration time, etc., all these will make the transport velocity vector of the nutrient salt change .4. In the waters of Dachang Mountain, the contents of total nitrogen and total phosphorus have been slightly polluted, the main pollutants are inorganic nitrogen and phosphate, but the pollution has improved, and the eutrophication trend of the water is not obvious. Overall is in poor nutrition level, organic pollution level is low. Nutrients promote plankton reproduction, but what is the amount of plankton in a given area, and in addition to the amount of nutrients in that area, there are currents that force plankton movement to increase or leave the decline. The results of biodiversity assessment showed that the catch species increased from 27 species to 36 species in the survey area of Dachang Mountain, and a growing number of species habitat indicated that the interest field in the area recovered better. The subsequent biodiversity index (H') is higher than the previous survey results, and the biodiversity index is increasing. The decrease of the evenness index (J') shows that there are three dominant species in the sea area of Dachang Mountain, Hexagrammos otakii, Gymnocor ymbus ternetzii and Charybdis japonica.Compared with other species, the three species are less competitive. Species abundance index (D') increased and species increased to 36 species. The results show that the current brings nutrients into the sea area, which can restore, reproduce and increase the species in the sea area. A very satisfactory result has been obtained in this project.
【学位授予单位】：大连海洋大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：Q178;P734

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