铁质船体对磁罗经海流计流向影响分析

在铁质船体周围进行海流观测,在没有外部罗经输入的情况下需要由仪器内部磁罗经确定海流方向,必然会受到船体磁场的影响。利用多组实测数据比较了由于船体影响产生的流向偏差,分析了偏差产生的原因以及可能的解决办法。     

潮流物理模型试验生潮控制时的复合模拟数据对接

根据几种不同情形探讨复合模拟中如何通过数值模拟为潮流物模试验提供开边界控制条件。对单边界物理模型,可由数模的调和常数得到物模边界控制所需的时间序列数据,实现单分潮、多分潮及大、中、小潮的模拟;对于历时较长的试验,可由数模得到长时间序列或周期性序列数据作为生潮的控制信号;对多边界模型,沿边界分为若干控制断面,由数模给出各断面的流量变化,对各断面分别进行流量控制;差时的复合模拟可使物理模型和数值模型互相提供边界条件或模型参数修正。     

胶州湾海域潮流动力特征及其与含沙量的关系

根据2009年胶州湾海域的悬沙、流速、流向的实测资料,应用短期资料的潮流准调和分析方法,对连续海流资料进行了分析,并结合悬沙资料,对含沙量与潮流之间动力关系进行了探讨。研究结果表明:该海域潮流属于正规半日潮流性质,半日分潮流的东分量大于北分量,潮流以带有旋转性质的往复流为主,涨潮流流向偏西,落潮流流向偏东。胶州湾内含沙量分布特征与海底沉积物粒径特征基本一致。含沙量在涨落潮的交替和流速的更迭作用下出现明显的周期性变化,含沙量的峰值基本与海域半日潮流特点相对应,几乎每1个流速峰值对应1个含沙量的峰值,含沙量的峰值一般出现在流速峰值之后。胶州湾口处流速和单宽输沙量都为最大,涨潮单宽输沙量大于落潮单宽输沙量,输沙方向为偏西向。     

粤西近岸环流研究进展

粤西近岸环流对粤西乃至北部湾海域的物质输送、水质环境、渔业养殖等都具有重要影响.本研究就粤西沿岸环流(尤其是夏季环流)的基本特征、驱动机制、及其与琼州海峡流关系等方面的研究进展进行了概述,并对存在的问题进行了探讨.前人对粤西沿岸流终年向西以及夏季沿岸流外侧存在气旋式环流等定性特征已达成共识,然而,对环流的主要影响机制以及与琼州海峡流的关系尚有争议,关于环流的定量结果也较为缺乏,还需进行长时间的连续观测以及适合近岸海域的数值模拟.     

Approximate velocity formula over mobile sediment bed induced by velocity-skewed waves and current

A velocity formula is proposed for flow over a mobile sediment bed induced by velocity-skewed waves and current. The formula is obtained by a separation of waves and current velocities and requires seven free variables related to free stream velocity and sediment characteristics. The formula includes two parts:(1) a wave part consisting of the free stream velocity and defect function, which considers phase lead, wave boundary layer thickness, and mobile bed level, and(2) a current part, which ch...     

地球磁场起源之粒子起电问题研究

粒子起电问题是解决地球磁场起源中固体地球内部电流形成问题的关键之一。通过引述电化学领域二相流起电机制,建立了有利于分析地球磁场起源的固体地球内部物质流动的双电层模型结构,即液/液界面双电层模型和液/固界面双电层模型,分析了地球外核物质流动及流动起电问题。在地球运动动力和运动定律作用下,地球外核物质的定向移动是形成地下电流、产生磁场的直接原因。研究了形成地磁场电流的一般算法及影响因素,探讨了“静电”的“动电”本质,讨论了双电层模型的适应性、起电电荷电性变化、局部气旋电流、磁异常等问题。指出固体地球内部物质起电电荷电性的改变是地磁场极性倒转主要原因。     

太阳大气等离子体的电流研究

该文讨论了太阳大气等离子体中电流的成因和对各种爆发活动的作用和影响,对目前的研究现状和存在的问题进行了分析讨论,指出虽然磁场是太阳物理观测和研究的关键要素,但是电流也是理解能量的传输与耗散、不稳定性的驱动和激发、等离子体的加热和粒子加速等太阳物理过程的重要概念.该文还提出了一个定性的改进电路模型,认为电流主要产生于太阳内部的发电机过程,同时电路在日冕部分的环形磁场位型也将产生部分新经典电流,通过磁通量管流入太阳大气,并在日冕区域通过磁场重联等过程释放能量.对该模型尚待解决的问题也进行了简单讨论.     

西安市停车资源现状与空间分布研究

针对目前各大中城市私有汽车数量不断上升、城市停车资源趋于饱和甚至过载的现状,以西安市三环内停车资源为例,分析了其空间布局、配套设施以及建设投资主体等方面的资源分布发展现状,并制作了相关专题地图,为城市停车资源修建与管理提供参考.结果 表明,西安市停车资源整体呈聚集分布,在经济发展较好的区域聚集特征明显;由政府部门投资兴...     

Impact of monsoon-driven circulation on phytoplankton assemblages near fringing reefs along the east coast of Hainan Island,China

Monsoonal hydrodynamic prevails over the east coast of Hainan Island induced by southwest monsoon (SWM) and northeast monsoon (NEM) which drives coastal Ekman divergence/convergence cycle and the reversal of Guangdong coastal current (GCC) between the sGCC in the SWM season and nGCC in the NEM season. We report the control of such hydrodynamics on biological properties such as phytoplankton assemblages in the east coast of Hainan Island. Physico-chemical and biological observations were carried out in two oceanographic cruises along the east coast of Hainan Island during SWM period (July–August) of 2008 and NEM period (March–April) of 2009. Results indicated that phytoplankton assemblages in coastal regions (fringing reefs and coastal shelf) changed dramatically accompanied with the reverse of monsoonal hydrodynamic processes, with chain-forming diatoms (mainly, Pseudo-nitzschia spp. and Thalassionema nitzschioides) dominating during SWM cruise when coastal Ekman divergence and the sGCC were prevailed, but the pelagic Noctiluca scintillans and Trichodesmium erythraeum dominating during NEM cruise when coastal Ekman convergence and the nGCC were prevailed. Furthermore, phytoplankton assemblages in fringing reefs along coastline were somewhat different from ones of coastal shelf, as fringing reefs are just located at dynamic boundary of offshore (or onshore) Ekman transport processes. Offshore diffusion of pelagic cells (such as T. erythraeum) driven by offshore Ekman transport process led to the lower abundance of T. erythraeum in fringing reefs than ones in coastal shelf during SWM cruise; on the contrary, onshore aggregation of pelagic cells (such as N. scintillans and T. erythraeum) driven by onshore Ekman transport process leads to higher abundances of N. scintillans and T. erythraeum in fringing reefs than ones in coastal shelf during NEM cruise; especially, N. scintillans formed bloom in fringing reefs. Last, we suggested that hydrodynamic processes must be taken into account in scientific management of fringing coral reefs health of the east coast of Hainan Island, especially during northeast monsoon season when blooming specie cells (such as N. scintillans) could be introduced from eutrophic South China mainland coast to the east coast of Hainan Island and piled to high-abundance at fringing reefs by monsoonal hydrodynamics.     

基于PAADCP 的海流流速的误差分析及校正方法

为了更加合理、有效地利用海流测速数据,必须进行误差分解和校正。通过分析相控阵声学多普勒海流剖面仪(PAADCP)测试海流流速的原理,提出了海试数据粗差区别与动态校正的算法,采用小波多尺度分析方法,降低了系统误差和随机误差,建立了海流流速的误差分析与校正方法。利用海试实测的垂向流速数据,分析了一般情况下的海流流速的误差,得到垂向流速的均值±0.02 m/s,误差精确度小于0.23 m/s,验证了方法的有效性及合理性。所得算法和方法对于海流测速数据的实时处理和后处理具有实用价值。