SWAN浅水波浪模式在渤海的应用研究——Phillips线性增长比例系数的改进

将国际上通用的SWAN波浪数值模式应用到渤海,以检验其适应性。通过对由风引起的波浪的增长和耗散作用源函数的实验研究,发现SWAN中所采用的Phillips线性增长部分的比例系数和波浪成长有较大的关系,此比例系数随摩擦速度变化(原模式取此系数为一常数)。基于模式试验,引入了一个新的Phillips线性增长项公式,并且利用3个风过程对模式的改进进行了验证。3个风过程的计算结果和实测值比较表明,计算结果在3个过程当中都得到了明显的改进。     

应用SWAN模型分析航道对波浪传播的影响

应用SWAN模型,采用多向不规则波计算了秦皇岛港航道改造工程前后4个具有代表性波向的波浪场,分析了航道对工程区4个不同方向波浪传播的影响并得到了航道沿程的波高分布.改造后的秦皇岛港航道呈折线型,长为24.4 km,相应的计算区域较大,使Boussinesq模型因网格过多而难以进行计算,而缓坡方程模型在处理多向不规则波时计算过于繁琐,SWAN模型在大区域、多向不规则波情况下能够较好地解决计算问题.运用该模型计算的结果表明,秦皇岛港航道改造工程后距航道较近区域的波态发生明显的变化,但工程海区的波浪整体传播规律没有发生大的改变.     

潮汐和流影响下长江口波浪场数值计算

采用SWAN模型和REF/DIF模型进行嵌套计算的方法来获取长江口海域实际波浪场.其中设计一种根据入射波向即时生成计算网格的方法,解决REF/DIF模型对于波浪入射角的限制从而实现两种模型的嵌套.为考虑水流和潮位分布的空间差异对波浪传播变形的作用,利用二维流场模型计算长江口的水位和流场过程,在实际波浪计算中引入了水位和水流作用.计算结果与观测资料的对比表明:1)SWAN模型和REF/DIF模型的嵌套计算方法可以作为提高浅水区域波浪计算精度的一种有效途径;2)水位和水流对长江口波浪计算的影响显著,考虑了水位和水流条件后,尤其是在大潮期间,能比较显著地提高计算精度.     

基于GIS的广西中小河流山洪气象风险监测预警系统

基于中尺度自动站雨量资料、欧洲中心（EC）细网格数值预报雨量资料、广西雷达数据,利用ArcGIS提取河流边界地理信息,通过用MICAPS、SWAN3．0系统二次开发,数值模式产品应用,面雨量对比等方法建立广西中小河流山洪气象风险监测预警系统。系统能自动生成各种气象要素的可视化警报、预报产品．经过在2012年汛期若干天气过程的应用显示了较好的监测预警作用,可以应用到精细化天气预报业务中。     

Implementation and modification of a three-dimensional radiation stress formulation for surf zone and rip-current applications

Regional Ocean Modeling System (ROMS v 3.0), a three-dimensional numerical ocean model, was previously enhanced for shallow water applications by including wave-induced radiation stress forcing provided through coupling to wave propagation models (SWAN, REF/DIF). This enhancement made it suitable for surf zone applications as demonstrated using examples of obliquely incident waves on a planar beach and rip current formation in longshore bar trough morphology (Haas and Warner, 2009). In this contribution, we present an update to the coupled model which implements a wave roller model and also a modified method of the radiation stress term based on Mellor (2008, 2011a,b,in press) that includes a vertical distribution which better simulates non-conservative (i.e., wave breaking) processes and appears to be more appropriate for sigma coordinates in very shallow waters where wave breaking conditions dominate. The improvements of the modified model are shown through simulations of several cases that include: (a) obliquely incident spectral waves on a planar beach; (b) obliquely incident spectral waves on a natural barred beach (DUCK'94 experiment); (c) alongshore variable offshore wave forcing on a planar beach; (d) alongshore varying bathymetry with constant offshore wave forcing; and (e) nearshore barred morphology with rip-channels. Quantitative and qualitative comparisons to previous analytical, numerical, laboratory studies and field measurements show that the modified model replicates surf zone recirculation patterns (onshore drift at the surface and undertow at the bottom) more accurately than previous formulations based on radiation stress (Haas and Warner, 2009). The results of the model and test cases are further explored for identifying the forces operating in rip current development and the potential implication for sediment transport and rip channel development. Also, model analysis showed that rip current strength is higher when waves approach at angles of 5° to 10° in comparison to normally incident waves.     

渤海海域冰水共存期的波能流密度推算

为给寒区海域的波浪能估算提供科学依据,提出一种合理推算冰水共存海域波浪条件及波能流密度的方法,该方法将海冰模型与水动力学模型耦合模拟得到的冰浓度以线性修正函数的方式纳入波浪模型的海面摩阻风速方程中,并基于MCT (model coupling toolkit)耦合器将海冰模型、水动力学模型与波浪模型进行实时耦合。基于该方法模拟了渤海冬季寒潮大风期间的海冰以及波能流密度的演化。模拟结果表明,在2012年2月5~8日寒潮大风期间,结冰区域占到渤海总面积的1/3,约有76%的渤海海域的平均波能流密度受海冰影响减小,其中辽东湾近岸的波能流密度平均受冰影响最多减小了100%,而渤海湾和莱州湾近岸受冰影响最多分别减小了60%和50%。即使是无冰覆盖的老铁山水道,其波能流密度的最大值也受冰影响减少了14%。耦合模拟可以更为准确地对渤海冬季的波能流密度分布进行评估,为波浪能发电厂选址提供依据。     

Analysis of SARAL/AltiKa Wind and Wave over Indian Ocean and its Real-time Application in Wave Forecasting System at ISRO

The current study aims to analyze the wind and wave parameters over Indian Ocean region obtained from first Ka –band altimeter AltiKa onboard SARAL, a collaborative mission of Indian Space Research Organization (ISRO) and Centre National d'Etudes Spatiales (CNES), France. It also demonstrates a real time application of SARAL data by assimilating the wave height in a wave model operational at the Space Applications Centre, ISRO. State-of–the art coastal wave model Simulating Wave Near shore (SWAN) is used for this purpose. The well-tested optimal interpolation technique is adopted for assimilation. Before proceeding to the assimilation per se, SARAL/AltiKa Wind and Significant Wave Height (SWH) have been validated using in- situ observations and WAVEWATCH III model. Apart from assessment of wind and wave data quality, this also served the purpose of providing error covariance to be used in assimilation. Supremacy of the assimilation run over parallel control run without assimilation has been judged by comparing the results with buoy observations at Indian National Centre for Ocean Information System (INCOIS). The statistics of validation of the assimilation run has been found to be extremely encouraging and interesting.     

1105号台风“米雷”台风浪模拟研究

以CCMP(Cross-Calibrated,Multi-Platform)风场驱动目前国际先进的第三代近岸海浪模式SWAN (Simulating WAves Nearshore),对1105号台风“米雷”造成的台风浪进行数值模拟,基于浮标观测资料,验证了模拟数据的有效性,并对台风浪场的分布特征进行分析.结果表明:(1)以CCMP风场驱动SWAN模式,可以较好地模拟“米雷”所形成的台风浪场;(2)模拟的有效波高(SWH——Significant Wave Height)与浮标观测SWH在波高变化的走势上具有很好的一致性,模拟数据的走势则较为平缓,观测数据跳跃较为明显,模拟的SWH具有较高精度,仅在数值上略低于观测SWH; (3) SWAN模式对“米雷”所形成的台风近中心大浪区、台风眼、台风尾迹等方面进行了较好地刻画.     

广义帕雷托分布在波浪极值推算中的应用

以CCMP风场(1988年1月~2010年12月)为驱动,本文采用第三代海浪数值模式SWAN对中国海海区进行风浪场的数值模拟,并利用浮标资料对驱动风场和计算有效波高进行验证。根据模拟的结果分别采用广义帕雷托分布(GPD)和常用的广义极值分布(GEV)拟合累积频率曲线并进行效果检验,进而分析和比较2种分布的优缺点,并运用广义帕雷托分布(GPD)模型进行重现期波要素的推算,分析GPD模型的应用前景。     

9210工程卫星广域网的信道共享技术

主要介绍了9210工程卫星广域中使用的随机接入技术—ALOHA的几个方案的工作原理