基于随机游动模型的北部湾水体动力特征解析

发布时间：2017-12-31 01:37

本文关键词：基于随机游动模型的北部湾水体动力特征解析　出处：《厦门大学》2014年硕士论文　论文类型：学位论文

【摘要】：为研究北部湾的水体动力特征,本文采用随机游动粒子追踪方法,建立了具有拉格朗日特性的随机游动模型。该模型在考虑水体扩散效果的同时,可以有效地避免对流扩散模型中可能的数值振荡及其导致的水交换计算偏差,还可以方便快速地实现驻留时间等水交换时间尺度的计算。该模型关于二维瞬时点源扩散的模拟结果与其解析值的比较表明它能够较好地模拟对流扩散问题。结合水动力模型,首先利用随机游动模型研究北部湾的水交换能力,计算北部湾水交换矩阵和水体驻留时间。结果显示,湾内水交换规律呈现出与环流结构相似的季节性变化特征；季风作用下的水体驻留时间较短,各分区之间水交换比较活跃；冬季东北风作用下的广西沿岸水驻留时间最长,红河河口水驻留时间最短；夏季西南风作用下广西沿岸水驻留时间最短,其水体可延伸至中部海域。其次,利用随机游动模型研究北部湾的水体迁移特征。研究结果表明,琼州海峡与南部湾口为北部湾湾内水体与外海水交换的重要通道。在冬季环流和潮流影响下,源地在琼州海峡西口的水体可影响北部湾东北水域,该区域水体具备粤西沿岸水的特征;而源地为海南岛西侧海域的水体被限制在海南临高邻近海域；夏季源地为琼州海峡西口的水体主要贴近雷州半岛和广西沿岸逆时针方向移动,流幅窄;源地为海南岛西侧海域的水体向北拓展距离仅在40～50km左右就转向西和西南方向。北部湾中部以西海域水体受入海径流的沿程影响,在局部范围是相当显著的。越南沿岸入海径流的影响范围主要集中于距海岸20-701km左右的范围内,冬季影响范围明显扩大,离岸可达30km左右,广西沿岸入海径流量相对较小,影响范围多局限在距海岸20km以内的近岸区域。最后,利用随机游动模型研究台风对中尺度海湾水体迁移的影响。结果显示台风路径东侧海域水体偏离原轨迹运动显著,受台风影响较大,西侧海域水体运动变化不大。从单纯潮、潮与月平均风、潮与台风三种不同条件下的粒子偏移初始位置距离差的对比中可以看出,海燕台风过境后对过渡性水域水体的动力过程影响最大,对越南南岸的水体影响最小。研究还表明,铁山港通过沙田以南湾口处与北部湾海水进行交换,湾内水体交换主要受潮汐控制,上层水体较下层水体水交换率大,湾口和湾中水交换较快；落潮期水体交换速度明显快于涨潮期；单点中性示踪粒子运动轨迹显示,儒艮保护区正处在铁山港与北部湾海水交换的活跃区内；山口红树林保护区受到沙田半岛本埠、石头埠和白沙河水体的影响。
[Abstract]:For the water power characteristics of Beibu Gulf, the random walk particle tracking method, established the model of random walk with Lagrange. The characteristics of the model in consideration of water diffusion effect at the same time, can effectively avoid the possible numerical oscillation of convection diffusion and the resulting water exchange model calculation error, also can realize a resident the calculation time of water exchange time scales. The simulation results of the model on the two-dimensional instantaneous point source diffusion and its analytical value shows that it can simulate the convection diffusion problem.
Combined with the hydrodynamic model, first using the random walk model of the North Bay water exchange capacity, calculation of Beibu Gulf water exchange matrix and water residence time. The results showed that the bay water exchange law shows seasonal variation characteristics similar to the monsoon circulation structure; under the action of the water residence time is short, the partition between the water exchange between active; winter northeast wind under the action of Guangxi coastal water residence time is the longest, the Red River estuary water residence time is very short; summer southwest wind Guangxi coastal water residence time is the shortest, the water can be extended to the central sea area.
Secondly, using the random walk migration characteristics of Northern Bay water model. The results show that the Gulf Strait and South Qiongzhou port is an important channel of Beibu gulf bay water and seawater exchange. In the winter circulation and under the current source in Xikou Qiongzhou Strait waters can affect the waters of the Northeast in the northern Gulf, characteristics the regional water has Yuexi coastal water; and the water source is on the west side of Hainan Island sea area is limited in Hainan Lingao adjacent waters; summer from west of the Qiongzhou Strait water close to the Leizhou Peninsula and the Guangxi coast clockwise movement of the narrow flow; for the water source in North Western Hainan Island waters expand distance only in 40 50km turned to the West and southwest. The northern Gulf waters west of the middle part of the water along the river runoff influence, in the local area is significant. The Vietnam coastal runoff. The ring range is mainly concentrated in the range of 20-701km away from the coast. The influence range of winter is obviously expanded, and the offshore area can reach 30km. The coastal traffic volume along Guangxi coast is relatively small, and its influence is mostly confined to the Nearshore Area within 20km of the coast.
Finally, using the random walk model of typhoon migration on Mesoscale Bay. The results showed that the typhoon path east sea water movement significantly deviated from the original track, influenced by the typhoon, the sea water movement. Little change from simple tide, tide and monthly mean wind, tide and typhoon compared three kinds of particle migration in different conditions of initial position the distance difference can be seen in the transitional waters of typhoon Haiyan water dynamic process of water impact, impact on Vietnam south of the minimum.
The research also shows that, through the South Bay mouth to Tieshan'gang Sha Tin and water exchange in the Gulf of Beibu Gulf, water exchange is mainly controlled by tide, the water to lower water exchange rate, water outlet and bay Bay exchange faster; ebb tide water exchange rate was faster than the high tide period; single point neutral particle trajectory tracing display. Dugong protection zone is in the northern Gulf seawater exchange and Tieshan'gang active zones; Shankou mangrove reserve by the peninsula Sha Tin port, port and the water stone effect.

【学位授予单位】：厦门大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.2

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