哈马黑拉涡旋的季节变异研究   总被引：1，自引：0，他引：1  

翟方国  胡敦欣  王庆业 《海洋科学》2013,37(11):85-94

利用1992年1月～2006年11月期间的ECCO2海洋同化数据资料,研究了海洋上层50m平均的哈马黑拉涡旋的季节变异特征。结果表明,哈马黑拉涡旋在5月开始出现,7月达到最强,3月和4月消失,这主要取决于新几内亚沿岸流的季节变化。新几内亚沿岸流4～11月为西北向,从12月到次年的2月为东南向。随着西北向新几内亚沿岸流的增强,哈马黑拉涡旋开始出现并增强。而随着西北向新几内亚沿岸流的减弱和反向,哈马黑拉涡旋减弱并消失。同时棉兰老海流在夏季的增强也有利于哈马黑拉涡旋增强。旨在研究哈马黑拉涡旋的季节变异特征及其影响因子,为进一步探讨其垂向结构、年际变异等时空变化特征和该区域的环流特征提供研究基础。  相似文献   

浙南沿岸海表面温度分布特征(英文)     

韩小燕  潘晓东  马林芳 《海洋通报(英文版)》2013,(1):27-38

文章根据浙南沿岸3个海洋观测站大陈、坎门、南麂站51a(1960～2010年)SST观测资料,进行统计分析,得出SST时空分布特征。结果表明,浙南沿岸的SST总体呈现北低南高的趋势,冬季南北差异最小,夏季南北差异最大;51a年浙南沿岸SST总体呈现上升趋势,上升速率为0.017°C/a;SST变化存在3.5a、5a～6a、2a～7a及11a左右的振荡周期;SST主要由年循环分量决定,谐波拟合效果良好。  相似文献   

MOSES软件在系泊浮体运动计算中的应用研究     

李怀亮  徐慧  谢维维  董璐  高巍 《海洋工程》2013,31(6):16-21

采用MOSES软件计算某起重船迎浪下的水动力性能和运动响应,并对该船进行缩尺比为1:50的模型试验。通过软件计算结果和试验结果的对比,分析计算模型的网格划分、二阶波浪力计算方法和粘性阻尼等关键参数的选取对MOSES计算系泊浮体运动的影响,为MOSES软件在系泊下运动计算方面提出建议。  相似文献   

台风作用下琼州海峡海域波浪特征分析   总被引：1，自引：0，他引：1  

耿宝磊  文先华 《海洋工程》2013,31(6):59-67

通过在拟建琼州海峡跨海大桥西线方案主通航孔位置布置波浪测点,采集到2012年13号台风"启德"和23号台风"山神"期间波浪数据,结合两场台风期间波浪频谱和方向谱的变化,分析了该区域在台风期间的波浪特征,并进一步对风浪和涌浪进行了判别。研究结果表明:1)台风"启德"期间,海域波浪谱峰周期在3.3⁸.0 s之间,最大谱峰值为7.92 m2/s,波浪方向为W8.0 s之间,最大谱峰值为7.92 m2/s,波浪方向为W^N向,且频谱和方向谱的变化过程反映了风浪到涌浪的转变;2)台风"山神"期间,海域波浪谱峰周期在5.0N向,且频谱和方向谱的变化过程反映了风浪到涌浪的转变;2)台风"山神"期间,海域波浪谱峰周期在5.0⁶.5 s之间,最大谱峰值为2.70 m2/s,波浪方向为E6.5 s之间,最大谱峰值为2.70 m2/s,波浪方向为E^ESE向,波浪以风浪为主;3)琼州海峡海域大周期波浪主要受到台风引起的涌浪影响,涌浪周期的范围大约在6.5ESE向,波浪以风浪为主;3)琼州海峡海域大周期波浪主要受到台风引起的涌浪影响,涌浪周期的范围大约在6.5¹0.0 s之间。  相似文献   

波浪作用下的泥沙尖点突变起动模式     

拾兵  刘勇  薛旖云  张靖 《中国海洋大学学报(自然科学版)》2013,(10):102-105

本文基于尖点突变理论,针对泥沙运动的复杂特征,建立了波浪作用下的泥沙起动模式,确定了希尔兹极值、相对粒径和反映波浪与泥沙之间相互作用参数的非线性方程,并对该方程进行了拓扑变换。该模式的计算结果与波浪水槽试验资料的对比分析说明,该模式尽管存在一定的系统误差,但是对于波浪作用下的泥沙起动流速的求解和运动状态判别与试验值基本吻合,进而证明了泥沙起动的突变特性和该模型的适用性。  相似文献   

Effect of incoming sediment on the transport rate of bed load in mountain streams   总被引：2，自引：1，他引：1  

Guo-An YU  Zhao-Yin WANG  Kang ZHANG  Tung-Chiung CHANG  Huaixiang LIU Dr. 《国际泥沙研究》2009,24(3):260-273

Field experiments were conducted on bed load transport in the Diaoga River, a mountain stream in southwest China, to study the variation of bed load transport with varying sediment supply. The rate of bed load transport is greatly affected by incoming sediment （load and size）. Under the same flow conditions, bed load transport rates may differ by three orders of magnitude depending on whether measurements were taken before or after the first flood of the year. The relation of the ＂bed load transport rate versus flow intensity＂ appears to have similar characteristics as a clockwise looped-rating curve. Experiments also were conducted during the non-flood season to study bed load transport processes with different incoming load from an upstream section. Bed load with different sizes can be grouped into two types： traveling bed load and structural bed load. Traveling bed load is composed of sediment finer than a critical size, De, and its transport rate depends mainly on the incoming sediment rate. The incoming sediment rate can alter the rate of bed load transport by three orders of magnitude. Structural bed load is composed of coarser sediment and its transport rate closely relies on the flow intensity.  相似文献   

Bedload transport of small rivers in Malaysia     

Zahra ZANGENEH SIRDARI  Aminuddin AB GHANI  Zorkeflee Abu HASSAN 《国际泥沙研究》2014,29(4):481-490

Numerous time-consuming equations, based on the relationship between the reliability and representativeness of the data utilized in defining variables and constants, require complex parameters to estimate bedload transport. In this study the easily accessible data including flow discharge, water depth, water surface slope, and surface grain diameter （ds0） from small rivers in Malaysia were used to estimate bedload transport. Genetic programming （GP） and artificial neural network （ANN） models are applied as complementary tools to estimate bed load transport based on a balance between simplicity and accuracy in small rivers. The developed models demonstrate higher performance with an overall accuracy of 97% and 93% for ANN and GP, respectively compared with other traditional methods and empirical equations.  相似文献   

Shallow sediment transport flow computation using time-varying sediment adaptation length   总被引：1，自引：0，他引：1  

Jaan Hui PU  Khalid HUSSAIN  Song-dong SHAO  Yue-fei HUANG 《国际泥沙研究》2014,29(2):171-183

Based on the common approach,the adaptation length in sediment transport is normally estimated astemporally independent.However,this approach might not be theoretically justified as the process of reaching the sediment transport equilibrium stage is affected by the flow conditions in time,especially for fast moving flows,such as scour-hole developing flows.In this study,the two-dimensional（2D） shallow water formulation together with a sediment continuity-concentration（SCC） model were applied to flow with mobile sediment boundary.A timevarying approach was proposed to determine the sediment transport adaptation length to simulate the sediment erosion-deposition rate.The proposed computational model was based on the Finite Volume（FV） method.The Monotone Upwind Scheme of Conservative Laws（MUSCL）-Hancock scheme was used with the Harten Lax van Leer-contact（HLLC） approximate Riemann solver to discretize the FV model.In the flow applications of this paper,a highly discontinuous dam-break,fast sediment transport flow was used to calibrate the proposed timevarying sediment adaptation length model.Then the calibrated model was further applied to two separate experimental sediment transport flow applications documented in the literature,i.e.a highly concentrated sediment transport flow in a wide alluvial channel and a sediment aggradation flow.Good agreement with the experimental data were obtained with the proposed model simulations.The tests prove that the proposed model,which was calibrated by the discontinuous dam-break bed scouring flow,also performed well to represent rapid bed change and steady sediment mobility conditions.  相似文献   

Near-bed sediment transport in a heavily modified coastal plain estuary     

Gao-feng LIU  Jia-xue WU  Yuan-ye WANG 《国际泥沙研究》2014,29(2):232-245

Numerous estuaries of the world have been strongly modified by human activities.These interferences can make great adjustments of not only sediment transport processes,but also the collective behavior of the estuary.This paper provides a typical case of a heavily modified coastal plain estuary of Sheyang on the China coast,where a sluice barrage was built in 1956 to stop the intrusions of storm surges and saline water.Four sets of instrumented tripods were simultaneously deployed along a cross-shore transect to continuously observe near-bed flow currents and sediment transport.The in-situ surveys lasted over a spring and neap tide cycle when a strong wind event occurred in the neap tide.Comparisons of flows and sediment transport between tide-dominated and wind-dominated conditions demonstrated the important role of episodic wind events in flows and sediment transport.The wind-induced currents,bottom stresses,and sediment transport rates were significantly greater when wind was present than corresponding quantities induced by the tides.The long-shore sediment transport induced by winds exceeds the cross-shore component,especially near the river mouth bar.These results indicate the noticeable importance of wave-dominated coastal processes in shaping topographic features.A regime shift of estuarine evolution under highly intense human forcing occurs from fluvial to marine processes.This finding suggests that the management strategy of the estuarine system should focus on the restoration of estuarine processes,rather than the present focus on inhibition of marine dynamics.  相似文献   

地形对包兰铁路沙坡头段防护体系的影响   总被引：1，自引：0，他引：1  

周娜  张春来  邹学勇  吴晓旭  张峰 《地理科学》2014,34(7):889-896

选择沙坡头铁路防护体系典型断面,利用野外风场观测与风洞模拟,讨论地形在道路防沙体系中的作用。结果表明,防护体系前沿栅栏沙丘下风向10倍沙丘高度的水平范围内,地表摩阻风速通常小于临界值;风速递减系数随防护距离的增大而增大,地形倾斜和起伏对贴地层风力减弱的贡献占防护体系风速削弱程度的43%。自流沙区至铁路路基,潜在输沙率迅速波动降低,其中地形变化使得防护体系内潜在输沙率降低50%以上。这表明,地形是沙坡头铁路防护体系发挥卓越功能的重要因素,栅栏沙丘已成为防护体系的重要构成部分。  相似文献