空间扰动引力的谱分析   总被引：1，自引：0，他引：1  

赵德军  吴晓平 《海洋测绘》2005,25(2):6-8

基于重力场的频谱理论，给出了扰动引力在全球平均意义下的功率谱表达式，揭示了扰动引力的传播特性。通过数值试验，给出了扰动引力随高度变化规律，并分析了不同高度上，扰动引力恢复重力场的最高阶数及相应分辨率。从理论上分析了航空重力测量探测重力场中高频信息的能力，对制定飞行方案有一定参考价值。  相似文献   

东太平洋多金属结核分布的二维趋势面分析   总被引：1，自引：0，他引：1  

章伟艳  张富元  马维林 《海洋学研究》2001,19(1):27-34

对规则网的 469个测站的多金属结核丰度和 93个测站的 Mn、 Cu、 Co、 Ni元素进行趋势面分析 ,经 F检验 ,各变量的变异性显著 ,拟合度较低 ,表明多金属结核丰度及 Mn、Cu、Co、Ni金属元素的控制因素比较复杂。趋势面分析结果与相关分析结果一致 ,Mn、Cu、Ni元素有极相似的趋势特征 ,有两个轴向分布 ,一个为东西向轴 ,高值区在东部 ,另一个为北西向轴 ,高值区在北西部 ;结核丰度与 Co也有极相似的趋势特征 ,高值区在西部。应用逐次趋势面分析的结果将结核丰度的地质特征分解成各种简单控制因素的叠加 ,使对多金属结核的控矿因素、分布规律和物质来源的研究方法多样化  相似文献   

闽江口水动力和污染扩散数值模拟   总被引：3，自引：0，他引：3  

江毓武  张珞平 《台湾海峡》1997,16(2):169-173

本文建立了闽江口二维水动力、污染扩散数值模型，模型采用ＡＤＩ双向隐式求解。在水动力模拟中，对岸界的丁坝有用线性边界进行拟合，并考虑到河口区侧向摩擦作用；在污染扩散模拟中，用动态拟合的方法对浓度水边界进行了较为合理的改进。计算结果表明，本模型是成功的。  相似文献   

Elucidating the dynamics and mixing agents of a shallow fjord through age tracer modelling     

Karin E. Gustafsson  Jrgen Bendtsen 《Estuarine, Coastal and Shelf Science》2007,74(4):641

The mixing agents and their role in the dynamics of a shallow fjord are elucidated through an Eulerian implementation of artificial tracers in a three-dimensional hydrodynamic model. The time scales of vertical mixing in this shallow estuary are short, and the artificial tracers are utilized in order to reveal information not detectable in the temperature or salinity fields. The fjord's response to external forcing is investigated through a series of model experiments in which we quantify vertical mixing, transport time scales of fresh water runoff and estuarine circulation in relation to external forcing.Using age tracers released at surface and bottom, we quantify the time scales of downward mixing of surface water and upward mixing of bottom water. Wind is shown to be the major agent for vertical mixing at nearly all depth levels in the fjord, whereas the tide or external sea level forcing is a minor agent and only occasionally more important just close to the bottom. The time scale of vertical mixing of surface water to the bottom or ventilation time scale of bottom water is estimated to be in the range 0.7 h to 9.0 days, with an average age of 2.7 days for the year 2004.The fjord receives fresh water from two streams entering the innermost part of the fjord, and the distribution and age of this water are studied using both ageing and conservative tracers. The salinity variations outside this fjord are large, and in contrast to the salinity, the artificial tracers provide a straight forward analysis of river water content. The ageing tracer is used to estimate transport time scales of river water (i.e. the time elapsed since the water left the river mouth). In May 2004, the typical age of river water leaving the fjord mouth is 5 days. As the major vertical mixing agent is wind, it controls the estuarine circulation and export of river water. When the wind stress is set to zero, the vertical mixing is reduced and the vertical salinity stratification is increased, and the river water can be effectively exported out of the fjord.We also analyse the river tracer fields and salinity field in relation to along estuary winds in order to detect signs of wind-induced straining of the along estuary density gradient. We find that events of down estuary winds are primarily associated with a reduced along estuary salinity gradient due to increased surface salinity in the innermost part of the fjord, and with an overall decrease in vertical stratification and river water content at the surface. Thus, our results show no apparent signs of wind-induced straining in this shallow fjord but instead they indicate increased levels of vertical mixing or upwelling during down estuary wind events.  相似文献   

大地问题的截面椭圆弧长新解     

黄晓颖  边少锋 《海洋测绘》2007,27(1):21-23

分析了以前大地问题中截面椭圆弧长计算方法的缺点，在运用Mathematic的基础上，提出了在这一问题上的计算方便、过程简单的新方法，并用该方法进行了一个实例计算，效果良好。  相似文献   

Crustal Structures of the Northernmost South China Sea: Seismic Reflection and Gravity Modeling   总被引：2，自引：0，他引：2  

Yi-Ching Yeh  Shu-Kun Hsu 《Marine Geophysical Researches》2004,25(1-2):45-61

The South China Sea (SCS) is a marginal sea off shore Southeast Asia. Based on magnetic study, oceanic crust has been suggested in the northernmost SCS. However, the crustal structure of the northernmost SCS was poorly known. To elaborate the crustal structures in the northernmost SCS and off southwest Taiwan, we have analyzed 20 multi-channel seismic profiles of the region. We have also performed gravity modeling to understand the Moho depth variation. The volcanic basement deepens southeastwards while the Moho depth shoals southeastwards. Except for the continental margin, the northernmost SCS can be divided into three tectonic regions: the disturbed and undisturbed oceanic crust (8–12 km thick) in the southwest, a trapped oceanic crust (8 km thick) between the Luzon-Ryukyu Transform Plate Boundary (LRTPB) and Formosa Canyon, and the area to the north of the Formosa Canyon which has the thickest sediments. Instead of faulting, the sediments across the LRTPB have only displayed differential subsidence offset of about 0.5–1 s in the northeast side, indicating that the LRTPB is no longer active. The gravity modeling has shown a relatively thin crust beneath the LRTPB, demonstrating the sheared zone character along the LRTPB. However, probably because of post-spreading volcanism, only the transtension-shearing phenomenon of volcanic basement in the northwest and southeast ends of the LRTPB can be observed. These two basement-fractured sites coincide with low gravity anomalies. Intensive erosion has prevailed over the whole channel of the Formosa Canyon.  相似文献   

分潮波模型多资料数值计算方法研究　Ⅰ.岸边资料运动学外推的第一边值方法     

潘文波  孙文心 《中国海洋大学学报(自然科学版)》1996,(1)

对于含多资料三维分潮波模型建立了一种岸边资料运动学外推的潮波第一边值方法，并对渤海的四大原湖波进行试算。结果证实本方法可行，该方法使潮波方程既满足第一边值问题，充分利用岸边测站资料，又保证岸界法向流速为零条件，符合物理意义。并对复型病态矩阵的收敛问题提出了一种可行性处理。  相似文献   

陆坡非旋转重力羽状流的数值模拟          下载免费PDF全文

王凯  占全安  施心慧 《海洋科学》2007,31(7):55-62

借助MITgcm模式使用二维非静力近似在水平方向采用不等间距网格,模拟了陆坡非旋转重力羽状流的流动。模拟显示陆坡上的重力羽状流的运动比较复杂。通过数值实验,发现改变地形或调整冷源强度都会影响沿陆坡下沉的低温高密度水的羽状流形态,潮汐亦会对重力羽状流有一定的影响。经计算发现在陆坡处,Richardson数小于1/4,宜发生Kelvin-Helmholtz不稳定性,并由卷挟导致环境流体与高密度流体混合,沿着斜坡加速下滑。  相似文献   

SII型海洋重力仪稳定平台颤动故障与排除方法     

邵关 《海洋测绘》2007,27(3):78-80

S型海洋重力仪是目前海洋重力测量中较为常用的一种仪器，其产品性能也逐步得到提高。介绍了进行全自动化控制升级后，最新引进的SⅡ型海洋重力仪使用中出现的稳定平台颤动故障现象及排除办法。  相似文献   

龙口的海风及其影响   总被引：4，自引：0，他引：4  

薛德强  赵绪孔 《海洋湖沼通报》1995,(3):1-9

本文运用龙口气象站近５年自记风资料及实测探空资料，分析了龙口海风的生消规律、海风强度、空间结构及海风生成后对温、湿度的影响。同时为分析海风环流对大气污染物的影响。本文提出了一个简单地计算热内边界层的方法。  相似文献