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   

海洋内波的控制方程组     

袁业立  乔方利  戴德君 《海洋科学进展》2003,21(3):243-250

从海水质量守恒律、盐量守恒律、动量守恒律、熵变化律和海水状态律出发，给出了低频变密度海洋运动的原始控制方程和它的各类实用形式。在推导的过程中着重明确控制方程各种近似形式的数学物理意义，这使我们在使用这些方程时更严格、更准确。  相似文献   

宁波-舟山海域污染物扩散的数值模拟   总被引：4，自引：0，他引：4  

蔡惠文  孙英兰  张越美  张燕  余静 《中国海洋大学学报(自然科学版)》2006,36(6):975-980

基于宁波-舟山海域潮流场,建立了该海域三维变边界的污染物扩散模型,对COD、无机氮、活性磷酸盐的浓度进行了数值模拟,并对界面源的影响进行了分析。结果表明:污染物浓度在海域内呈由西北向东南方向递减的趋势;COD浓度在大部分海域满足一类水质标准,无机氮和活性磷酸盐浓度在研究海域超出二类水质标准;研究海域的界面源对该海域污染物浓度”贡献”在85%以上。  相似文献   

Mechanism for enhanced diffusivity in the deep-sea perpetual salt fountain     

Xinrong Zhang  Shigenao Maruyama  Koutaro Tsubaki  Seigo Sakai  Masud Behnia 《Journal of Oceanography》2006,62(2):133-142

The mechanism of enhanced diffusivity occurring in the deep-sea perpetual salt fountain has been investigated experimentally and numerically. Some factors which possibly contribute to the enhanced diffusivity were found to be the pipe oscillation with ocean waves and its baffled wall surface. Field experiments in the ocean (Onagawa Bay of Miyagi, Japan) and numerical simulations were performed to study and confirm the dynamics of the flow and heat transport with enhanced diffusivity occurring in upwelling deep-sea water. The agreement between the field experimental data and the numerical solutions of an oscillating-wall boundary condition imposed on the baffled pipe is encouraging, and it indicates the baffled pipe surface subject to the oscillatory motion leads to the enhanced diffusivity. The buoyancy force and then upwelling velocity can be greatly increased by the enhanced diffusivity. The dominant mechanism is the occurrence of complicated vortices and vortex shedding leading to efficient mixing and enhanced diffusion.  相似文献   

N₂O Production, Nitrification and Denitrification in an Estuarine Sediment   总被引：1，自引：0，他引：1  

T. Usui  I. Koike  N. Ogura 《Estuarine, Coastal and Shelf Science》2001,52(6):769

The mechanisms regulating N₂O production in an estuarine sediment (Tama Estuary, Japan) were studied by comparing the change in N₂O production with those in nitrification and denitrification using an experimental continuous-flow sediment–water system with¹⁵N tracer (¹⁵N-NO−3 addition). From Feburary to May, both nitrification and denitrification in the sediment increased (246 to 716 μmol N m⁻² h⁻¹and 214 to 1260 μmol N m⁻² h⁻¹, respectively), while benthic N₂O evolution decreased slightly (1560 to 1250 nmol N m⁻² h⁻¹). Apparent diffusion coefficients of inorganic nitrogen compounds and O₂at the sediment–water interface, calculated from the respective concentration gradients and benthic fluxes, were close to the molecular diffusion coefficients (0·68–2·0 times) in February. However, they increased to 8·8–52 times in May except for that of NO−2, suggesting that the enhanced NO−3 and O₂supply from the overlying water by benthic irrigation likely stimulated nitrification and denitrification. Since the progress of anoxic condition by the rise of temperature from February to May (9 to 16 °C) presumably accelerated N₂O production through nitrification, the observed decrease in sedimentary N₂O production seems to be attributed to the decrease in N₂O production/occurrence of its consumption by denitrification. In addition to the activities of both nitrification and denitrification, the change in N₂O metabolism during denitrification by the balance between total demand of the electron acceptor and supply of NO−3+NO−2 can be an important factor regulating N₂O production in nearshore sediments.  相似文献   

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   

葫芦岛沿岸海陆风特征及其环境效应     

刘吉敏  黄泓  王学忠 《气象与环境科学》2019,42(1):79-85

利用葫芦岛观测站1980—2009年观测资料,分析了葫芦岛沿岸海陆风风速的季节特征和日变化规律,以及海陆风环流对沿岸环境的影响。结论如下:1)葫芦岛站点在冬季出现海陆风日数最多,其他依次为秋季、夏季和春季。陆风风速从春季到冬季呈现递减趋势;海风在春季最大,其次为秋季的,冬季的最小。总体上,海陆风日中海风要强于陆风。2)对海陆风风速椭圆拟合结果表明,海陆风在10:32由陆风转化为海风,海风在16:32达到最大,在21:42由海风转化为陆风,陆风在04:32达到最大。3)由于海风的存在,沿岸地带在春夏两季日最高气温在12时出现,秋冬季的在13时出现。4)能见度日变化在四季中表现一致,早晨能见度转好的时刻比最低气温出现时刻滞后约2 h,在海风维持较长时间后空气绝对湿度增加导致能见度开始转差。5)冬季静止型海陆风日比例最高,再循环型海陆风日在秋季出现最多,而夏季通风型海陆风日出现最多。  相似文献   

巨厚含水层注浆浆液扩散半径及影响因素研究——以峰峰矿区为例     

刘永彬 《中国煤炭地质》2022,(1)

总结了饱水裂隙岩体中浆液的球形扩散模型和柱状扩散模型。通过对不同注浆模型中各参数,如浆液黏度、岩石孔隙率、注浆孔半径、岩体渗透系数及启动压力等对注浆扩散半径的影响分析,认为注浆孔半径和岩石孔隙率对宾汉姆流型浆液扩散影响不明显,而影响浆液扩散半径的主要因素是浆液黏度、岩体渗透系数及启动压力梯度。最后针对峰峰矿区,通过计算提出了包括注浆压力和注浆结束压力的注浆参数理论值。  相似文献