【作者】 张进峰；

【导师】 黄立文；

【作者基本信息】 武汉理工大学 ， 交通信息工程及控制， 2009， 博士

【摘要】 台风是热带洋面能量大量聚积和释放所诱发的强烈天气现象,是地球上破坏力最大的几种气象灾害之一,我国每年都会不同程度地遭受台风引起的强风、暴雨、风暴潮及其巨浪的袭击。台风是在热带洋面上形成和发展,台风和海洋是通过热力和动力过程的相互作用而耦合在一起的,在研究台风过程的海-气相互作用时,必须全面考虑大气诱导的海洋变化对大气的效应和海洋诱导的大气扰动对海洋的效应,即海-气间双向的响应和反馈的影响,在此基础上的海-气耦合模式的发展促进了台风-海洋相互作用的研究。海浪作为存在于大气-海洋界面的一种小尺度天气现象能够直接地影响海-气相互作用,它是参与大气边界层和上层海洋之间动量、热量和物质交换的一个重要物理过程。因此,通过发展大气-海浪-海洋全耦合模式成为研究海-气相互作用和海洋环境变化的重要手段,是目前国际上较为前沿的研究方向。本文回顾了近年来国内外有关大气-海浪-海洋耦合模式的研究现状,海浪对海-气相互作用影响的研究主要围绕海面粗糙度展开,海面粗糙度是表征海面空气动力学粗糙程度的物理量。最早关于海面粗糙度计算的经典参数化方案是由Chamock (1955)提出,他提出粗糙度依赖于风速的变化,并由量纲分析导出粗糙度与风速的关系；随后实施的大量观测试验表明,海面粗粗度与风浪状态有关,但由于观测实验本身及实验所在海域风浪的分布特征都不相同,没有一个明确、普遍适用于各个海域的关系式。国内外研究中开展了建立大气-海浪耦合模式来研究基于海浪状态的海面粗糙度对海-气相互作用过程的影响机制,但大气-海浪-海洋是一个完整的系统,仅考虑大气-海浪之间的耦合作用显然不能准确地反映出海-气相互作用的全过程。本文在课题组原有的中尺度海-气耦合模式LASG-MCM的基础上建立了新的区域大气-海浪-海洋耦合模式(亦简称区域海-气-浪耦合模式),对海-气界面的动力作用和热力作用过程进行参数化,并引入海面粗糙度最新理论研究和观测试验成果,改进大气模式中计算海面粗糙度的Charnock经典参数化方案,更为真实地考虑上层海洋对大气的反馈机制,进一步优化耦合模式对海-气界面物理过程的描述。本文选择南海0214号强热带风暴"Vongfong"和黄东海0414号台风"Rananim"两个典型的台风过程,利用建立的区域大气-海浪-海洋耦合模式进行海面粗糙度参数化方案敏感性试验,通过对敏感性试验与控制试验的模拟结果进行对比分析,研究考虑海浪状态的海面粗糙度参数化方案对台风过程中海-气-浪相互作用过程的影响。研究结果表明,考虑了海面粗糙度的反馈后,对热带气旋的移动路径的模拟有一定改进,但总体改进较小；海-气动量通量受到的影响显著,敏感性试验模拟的海面风场均较控制试验明显减弱,摩擦速度明显增加,且影响的区域主要位于台风的右半圆,具有明显的右偏性；海洋环流背景场特征受到显著影响,流速较控制试验有所减小,且具有明显的右偏性；耦合模式较好地模拟了台风过程中海浪场的分布,敏感性试验各方案模拟的有效波高明显减小,减小的区域与海面风场基本一致。台风内部海面风应力的减小使得海水垂向混合减弱,引起SST上升,SST上升直接导致近地层气温上升,近地层气温上升的区域与SST的升温区域基本一致；各海面粗糙度方案引起潜热通量的变化与SST的变化分布具有较好的一致性,在整个台风影响的区域内,潜热通量均有显著增加；在此过程中,感热通量变化不显著,主要由于SST上升的幅度和范围都较小,感热通量变化很小；在台风中心区域内垂直运动有所加强,主要是SST上升引起台风中心的上升运动增强；台风中心的上升气流把低层的高温、高湿空气向高空输送,引起台风上层的升温较为显著,使得在台风中心的上空的暖核中心附近相对湿度也有所增加；无论是对流性降水还是非对流性降水强度均有增加,且对流性降水降水量增加较大,敏感性试验模拟的降水量与实况更为一致,很好地解决了原海-气耦合模式对降水模拟偏弱的问题,降水落区与实况也更为接近。在上述分析的基础上,本文提出了海面粗糙度对海-气-浪相互作用的影响机制。本文最后结合某沿海港口进港船舶航行仿真试验实例,将海浪数值模拟结果与船舶操纵模拟器结合,并对数值场与定常风浪条件下的航行仿真试验结果进行对比分析,定量地评估了仿真试验中数值海浪场引起的航迹带偏移量。试验结果表明,波浪作用力使得船舶在进港航行过程中的航迹带发生偏移。更多还原

【Abstract】 Typhoon is one of the most violent storms in the world, which accumulates and releases a great deal energy in the tropical ocean surface. It does great damage to our country by its strong wind, heavy rain, high tide and huge wave. Typhoon only forms and develops in the tropical ocean surface, and it couples with the ocean by dynamic interaction processes and thermal interaction processes. When researching the air-sea interaction in the typhoon process, the effect of ocean change induced by the atmosphere on the atmosphere motion and the effect of atmospheric disturbance induced by the ocean on the upper ocean must be fully considered. This is the response and feedback at air-sea interface. Ocean wave is smallscale weather phenomenon, which may contribute to the air-sea interaction. Accordingly, the development of the atmosphere-wave-ocean coupled model is the important measure to explore the air-sea interaction and ocean state change, and it is the international cutting-edge research directions.This paper first reviewed the research of coupled atmosphere-wave-ocean model in recent years. The sea surface roughness is chosen as the influencing factor when the effect of ocean waves on air-sea interaction is considered. The earliest parameterization of sea surface roughness is put forward by Charnock (1955), and the main idea of the parameterization is that the sea surface roughness depends on the wind speed. The results of subsequent observational experiments show that the sea surface roughness depends on the ocean surface waves, and there are no definite and applicable expressions which can be used in any sea area. The coupled atmosphere-wave model is used to explore the effect of sea surface roughness on air-sea interaction, but the air-wave-sea interaction is an integrated system, therefore, the coupled atmosphere-wave model can not reflect the full process during the air-sea interaction.In this paper, the regional coupled atmosphere-wave-ocean model is developed at the base of the original mesoscale coupled air-sea model (LASG-MCM). The dynamic interaction processes and thermal interaction processes at air-sea interface are parameterized in the coupled model, and the sea surface roughness parameterization is introduced into the model, which is based on the latest theoretical and observational research achievement. The classical Charnock parameterization is substituted by several new sea surface roughness parameterizations, which are more exact means to express the feedback from the upper layer ocean to atmosphere.Two representative typhoon processes are chosen and simulated using the regional coupled atmosphere-wave-ocean model, which are the 0214 Vongfong in the South Sea and 0414 Rananim in the Yellow and East Sea. The results show the path is indistinctively influenced by the sea surface roughness, the ocean surface wind speed decreases and the friction speed increases, especially to the right of the path. The ocean current speed and significant wave height are also reduced and the variational area is nearly the same to the wind field. The decrease of ocean surface wind stress weakens the ocean vertical mixing, and then sea surface temperature (SST) rises. The rise of SST results in the increase of ocean surface air temperature and latent heat fluxes, the change of sensible heat fluxes is not evident. The increase of SST also enhances the vertical motion, the updraft transports the high temperature and highly wet air from the lower layer to the upper layer in the typhoon center, and it also induces the increase of air temperature and relative humidity in the upper layer. This process strengthens the warm core and the precipitation, the precipitation simulated by the coupled model is more consistent with observation data.Finally, marine simulation is conducted using the example of entering the fairway in one seaport, the simulated wave field is applied in the ship navigation simulator. The excursion of the track is due to the simulated wave field data as compared with steady wave.更多还原