【作者】 王瑞学；

【导师】 岳前进； 季顺迎； Hayley H.Shen；

【作者基本信息】 大连理工大学 ， 固体力学， 2010， 博士

【摘要】 在研究海冰与全球气候系统的相互作用以及解决在极区和亚极区自然资源开发中所面临的海冰问题时,海冰数值模拟的时效性和精确性一直是人们关注的重点和研究的关键内容。本论文着重于海冰动力学数值模拟中的计算方法以及波浪与海冰相互作用两方面的研究。针对渤海以及极区冰缘区内海冰在风、浪、流等作用下表现出来明显的区域性和间断性的动力特征,本文发展了一个混合朗格朗日-欧拉方法以更有效准确地模拟海冰的动力过程。利用该方法对规则区域内的海冰堆积过程和涡旋风场作用下海冰的演化过程进行模拟,结果表明该方法可有效准确地模拟海冰的动力特性；采用该方法对渤海海冰动力学进行72小时数值模拟,计算结果与卫星观测数据和现场定点观测数据相吻合。在当前所有的数值模式中均忽略了波浪的影响,或将波浪的影响隐含地包括到其他参数的参数化过程中。然而,在更精细的中小尺度海冰数值模式中,波浪对海冰的动力和热力过程的影响必须加以进一步评估,这就需要对冰区内的波浪特征进行准确地确定。为了研究不同冰类型冰区对波浪传播特征的影响,本文对波浪在冰区内传播的弥散关系进行了系统的研究。本文首先描述了在HSVA进行的波浪在屑冰-莲叶冰混合冰区传播的实验室实验,并将实验结果与粘性模型对比,结果表明：粘性模型并不足以描述波浪在不同类型冰区内的传播特征。然后,根据冰缘区的形态特征,提出并发展了波浪在冰区内传播的粘弹模型,该粘弹模型不仅可以描述波浪在各种冰类型冰区内的传播特征,还统一了人们之前提出的各种数学模型,为该方面的研究提供了系统的理论框架。由于波浪从开阔水传入粘弹冰区后有可能产生数个不同的主导波模式,本文利用本征函数展开-匹配法对粘弹模型的反射和透射系数进行了求解,得到了不同波模式的波幅,并讨论了不同参数条件下的表观波特征。之后,本文结合波浪在冰区内传播的实验室实验,应用粘弹模型反推了实验所测冰盖的粘度和弹性模量,并探讨了利用实验室实验验证粘弹模型的注意事项。为了评估波浪对海冰生长速率的影响,本文利用两次冷室内冰与波浪相互作用的实验结果,计算了海冰-大气间的热传导率,实验结果表明：波浪作用下的海冰生长速率是无波作用下海冰生长速率的二倍,不同的波浪特征对海冰生长速率的影响不同。更多还原

【Abstract】 Better forcasting sea ice conditions is the most concern for studying the interactions between sea ice and globle climate system, and for solving the sea ice problems encountered in offshore applications such as navigation and expoitation of natural sources. This thesis focuses on the numerical method for sea ice dynamics and wave-ice interactions.In the Bohai Sea or the marginal ice zone, various dynamical characteristics such as breakup, rafting and ridging are ofter observed. In this thesis, a hybrid Lagrangian-Eulerian (HLE) method is developed to simulate the sea ice dynamics accurately and efficiently. With the HLE model, the ice ridging process in a rectangular basin and the sea ice dynamical process in a vortex wind field are simulated. The simulated results show that the HLE model can simulate the sea ice dynamics accurately and efficiently. The HLE model is also applied to model the sea ice dynamics in the Bohai Sea. The simulated ice thickness, ice concentration and ice velocity match the saterllite images and the field observed data well.Wave-ice interactions, which have been ignored or crudely parameterized in all present sea ice models, need to be included into the sea ice model to further improve the accuracy of the sea ice modeling. Wave characteristics play a key role in sea ice dynamical and thermodynamical processes. To investigate the ice effect on wave propagation, the dispersion relation for waves propagating into different types of ice cover is studied systematically. A laboratory experiment was carried out to study the wave propagating through ice covers consisting of a grease and pancake ice mixture. The comparision between experimental results and the two-layer viscous model shows that modeling the tested ice layer as a viscous fluid is not sufficient to describe the observed dispersion relation and amplitude attenuation. Based on the ice morphology in marginal ice zone, a visco-elastic model is proposed to describe the propagation of gravity waves into various types of ice cover. The visco-elastic model bridges the gap among the existing models and provides a unified tool for wave-ice modelers to parameterize the Polar Regions populated with various types of ice cover. The dispersion relation, however, contains several propagating wave modes. The eigenfunction expansion-matching method is used to solve the transimision coefficients of each wave mode. Apparent wave number and attenuation rate are calculated for different conditions. The visco-elastic model is applied to the laboratory experiment to inversely determine the viscosity and elasticity of the tested ice covers. The further validation process using the laboratory experiment is discussed. To estimate the wave enhanced ice production rate, the ice production rates under wave condtions are calculated from two experiments conducted in HSVA. The results show that the total ice production is enhanced under wave conditions, and the ice production rates under wave conditions could be twice as large as the calm water one.更多还原