Distribution Characteristics of Mean Seawater Temperature Related to the Thermocline in the Deep-Water Area of Nansha     

邱章  蔡树群  朱良生 《海洋通报(英文版)》2001,3(2)

On the bisis of determining the there elements of themocline ( depth [upper bound depth ], thickness and intensity ) and the maximum vertical temperature gradient of the surveying station, the paper calculates the mean temperature of the Nansha deep-water surveying station within the upper-bound depth layer of thermocline and the mean temperature below the lowerbound depth of thermocline between the 300m and 800m layers,respectively. Analysis indicates that the horizontal distribution of mean seawater temperature shows a distinct trend of the lowtemperature seawater slowly moving from tbe northeast to the southeast of Nansha,which seems to have been driven by the Northeast Monsoon. The larger the vertical temperature radient is, the greater is its capability of preventing the heat of the upper seawater from diffusing into the deeper layers on the vertical direction.  相似文献   

苏北辐射沙洲海域水文特征与COD潮扩散计算分析     

罗锋  李瑞杰  朱宇新 《海洋湖沼通报》2007,(Z1)

采用平面二维水动力及污染物输运模型.针对研究海域的水动力特性.应用潮流场作为背景场驱动控制污染物浓度的对流扩散方程,利用有限元方法对苏北辐射沙洲海域大、中、小潮水动力特征及如东洋口港附近污染物输运进行了计算分析。计算结果与实测结果比较表明:计算所得潮流场合理.辐射沙洲区部分潮流脊间水道的潮流运动具有明显的定向往复流形式,潮流强,潮差大.且形成了辐射状潮流流炀;排污口排放的污染物的扩散影响范围不大,不利潮型为小湖,大潮和中潮情况下,污染面积有所减小。  相似文献   

烟台套子湾污水处理厂扩建后邻近海域水质预测     

魏娥华  孙英兰  王翠  付会 《海洋湖沼通报》2007,(Z1)

以龙洞咀至养马岛邻近海域二维潮流模型为基础,建立污染物输运模型。预测烟台套子湾污水处理厂二期工程建成后对附近水域水质的影响,并进行环境风险事故影响预测。结果表明。正常运行时.污染物的超二类水域全部位于混合区内部,对附近海域环境影响不大,事故时无机氮和活性磷酸盐的排放会对该海域造成一定的污染,效应对污水处理厂加强管理.采取一定的防范措施.防止风险事故的发生。  相似文献   

渤海溢油数值预报研究   总被引：7，自引：0，他引：7  

刘钦政  张存智  刘煜  李燕  白珊  张建华 《海洋预报》2005,22(Z1):70-76

以溢油漂移扩散模式为核心,采用"油粒子"方法来模拟溢油在海洋环境中的漂移扩散行为,与业务化渤海三维海洋数值预报模式、中尺度海洋风场数值预报模式相衔接,获得海流、海面风场等海洋环境预报产品作为溢油模式的外强迫,建立了渤海溢油数值预报系统.本文简要介绍了该系统的组成、运行机制和模拟试验情况,并讨论了建立我国全海域溢油预报系统的有关问题.  相似文献   

南海东北部表层水体水平涡动扩散的~(228)Ra示踪研究     

黄奕普  姜德盛  徐茂泉  陈敏  邱雨生 《热带海洋学报》1997,(2)

研究了1994年8－9月南海东北部表层海水中228Ra的分布特征。采用Mn－纤维富集海水中的Ra同位素，通过其子体228Ac的β计数法来测量228Ra。表层海水中228Ra的放射性比活度从2．48Bq·m－3变化到4.47Bq·m－3，平均值为3.24Bq·m－3。228Ra的水平分布表现为调查海区东北部比活度较高，这与该航次的226Ra的分布特征相一致。根据各断面的228Ra放射性比活度与离岸距离之间的负相关关系，计算了它们所对应的水平涡动扩散系数，并讨论海域的地貌特征对228Ra比活度分布的影响。这些研究结果对表层水体的混合、交换，尤其是可溶性污染物的迁移、扩散以及海域的自净作用的研究都具有实际意义。  相似文献   

The effect of biological and physical disturbances on the transport of arsenic from contaminated estuarine sediments     

Gerhardt F. Riedel  James G. Sanders  Richard W. Osman 《Estuarine, Coastal and Shelf Science》1987,25(6)

From the distribution of dissolved and solid arsenic species in a contaminated estuarine sediment and measured rates of flux of the various arsenic species we propose an empirical model for the cycling of arsenic between sediments and water column. The chemical form of arsenic in the sediment was largely determined by the redox state of the sediment. Arsenite was the dominant dissolved and solid species in the deeper reduced sediment, and arsenate was dominant in the oxidized surface layer. Arsenite in the interstitial water diffused toward the surface layer, where it was mostly oxidized to arsenate prior to leaving the sediments. Some arsenate adsorbed to the surface sediments and produced a surface layer enriched in arsenic. Small concentrations of methyl and dimethyl arsenic were produced in the sediments, and these also diffused into the overlying water.Nereis succinea, a burrowing polychaete, affected distribution and flux of arsenic from the sediments by its production of irrigated burrows. These burrows increased both the effective surface area of the sediment and the diffusion of arsenic by a factor of five. When the relative effects of the activities of Nereis succinea and physical resuspension are compared, results indicate that although physical resuspension can produce large pulses of materials from contaminated sediments, continuous biological activity is likely to be more important in the mobilization of contaminants from sediments in many estuarine environments.  相似文献   

水动力与生态耦合的赤潮藻类生长模型研究   总被引：1，自引：0，他引：1  

田峰  葛根  杨晨 《海洋技术学报》2007,26(2):34-37

针对近岸海域赤潮藻类生长及分布的特点,将简化了的赤潮藻类模型与水动力学中的对流扩散方程相耦合,建立了一个水动力与生态耦合的赤潮藻类生长的深度模型。模型中用一个积分形式的指数函数模拟了藻类生长过程,用一个一阶线性函数近似模拟了藻类的死亡过程,用藻类浓度的一阶导数项模拟藻类的输运过程,用浓度的二阶导数模拟了藻类的扩散过程,并用高精度的三阶迎风格式对模型进行了数值模拟,结果表明,该模型能正确的反映藻类的生长特点,与实际情况吻合良好。  相似文献   

H₂O diffusion models in rhyolitic melt with new high pressure data     

Huaiwei Ni  Youxue Zhang   《Chemical Geology》2008,250(1-4):68-78

Water diffusion in silicate melts is important for understanding bubble growth in magma, magma degassing and eruption dynamics of volcanos. Previous studies have made significant progress on water diffusion in silicate melts, especially rhyolitic melt. However, the pressure dependence of H₂O diffusion is not constrained satisfactorily. We investigated H₂O diffusion in rhyolitic melt at 0.95–1.9 GPa and 407–1629 °C, and 0.2–5.2 wt.% total water (H₂O_t) content with the diffusion-couple method in a piston-cylinder apparatus. Compared to previous data at 0.1–500 MPa, H₂O diffusivity is smaller at higher pressures, indicating a negative pressure effect. This pressure effect is more pronounced at low temperatures. Assuming H₂O diffusion in rhyolitic melt is controlled by the mobility of molecular H₂O (H₂O_m), the diffusivity of H₂O_m (D_H2Om) at H₂O_t ≤ 7.7 wt.%, 403–1629 °C, and ≤ 1.9 GPa is given by