台风对西北太平洋气旋涡的影响

发布时间：2018-05-14 01:00

本文选题：台风 + 海洋气旋涡　；参考：《中国科学技术大学》2015年硕士论文

【摘要】：台风对海洋的影响是“台风-海洋”相互作用的重要分支,海洋(气旋和反气旋)中尺度涡在海洋中普遍存在,且对混合、物质的输运、能量的传播等诸多海洋过程有重要贡献；所以研究台风对中尺度涡的影响有重要意义。本文利用卫星遥感的海表温度、海表高度、海表盐度资料和浮标直接测量的海水温度、盐度廓线,结合建立的台风风场模型,就海洋气旋性中尺度涡对台风的响应开展了-些分析研究。首先选取了2012年三级台风“派比安”,分析了其对海洋的影响。该台风经过研究区域(126。E-133。E,17。N-25.5。N)后,海表温度下降和海表盐度上升,在混合层上述两个要素也是同样的变化。最低点的海表高度从-20cm下降为-53cm,如此显著地变化一方面与台风的影响有关,另一方面与中尺度气旋涡的合并密切相关。在台风中心,海表盐度的下降是海水蒸发、表层海水湍流混合和下层海水涌升与降水稀释作用竞争的结果。另外用一个台风风场模型计算了Ekman抽吸导致的水体上升距离,并由气旋涡中典型上升流速度估算了涡中上升流抬升的距离,这两者的数值和与浮标廓线反映出的水体上升距离相吻合。从而解释了温跃层以下水体中同一深度处温度和盐度的变化是水体上升造成的。然后对2001-2008年15个超强台风经过20个气旋涡区域时对这些涡造成的影响进行了统计分析。目的是找出影响海洋气旋涡变化的关键因子。在这20个涡区域中,仅有两处在台风过后出现新海洋气旋涡,这表明大多数情况下,台风不能诱发产生新的海洋气旋涡。通过对3个台风参数与描述涡变化的6个变量做线性回归分析,发现强迫时间与这6个参数的相关性最好,这是由于该量结合了台风强度、台风尺度和移动速度等多个因素,可以把强迫时间作为反映涡变化的指示因子。另一方面,统计时满足条件的例子较少,表明台风对海洋中尺度气旋涡的影响是否显著可能需进一步研究。最后利用建立的台风风场模型和海表高度、海表流速数据分析了台风输入到海流、海浪、海洋上层、海洋深层及通过海表摩擦耗散的能量。分析台风“派比安”对研究区域做功的情况,表明台风经过时并不是对气旋涡内每一点处海流都做正功,台风对海流做正功还是负功根本上是由其与涡的相对位置决定的。台风对海流做功功率、对海浪做功功率和台风通过海表摩擦耗散的功率,三者量级分别是1O-1W/M2、100W/M2、101W/m2。通过海表摩擦耗散的功率和能量,与对海浪做功功率和功图相似,耗散功率和能量较大的地方也在风速较大位置,最大功率超过50W/m2,耗散的能量也达到1OMJ/M2。另外分析2001-2012年平均输入到深层和表层的能量发现在台风经过频率较高的地方,输入的能量较大,可达40KJ/m2。这些海域台风就是向深层海洋输入能量的关键区域。
[Abstract]:The influence of typhoon on the ocean is an important branch of the "Typhoon-ocean" interaction. The mesoscale vortices of the ocean (cyclones and anticyclones) are ubiquitous in the ocean, and they are mixed and transported. Many ocean processes, such as energy propagation, have important contributions, so it is important to study the effects of typhoons on mesoscale vortices. In this paper, sea surface temperature, sea surface height, sea surface salinity data, sea temperature and salinity profile measured directly by buoy are used to establish typhoon wind field model. The response of ocean cyclonic mesoscale vortices to typhoons is studied in this paper. First of all, the influence on the sea was analyzed by selecting three-class typhoon Pipian in 2012. The sea surface temperature decreased and the sea surface salinity increased after the typhoon went through the study area 126.E-133.Ef17.N-25.5.N. the above two elements also changed the same in the mixed layer. The sea surface height of the lowest point decreases from -20 cm to -53 cm, which is related to the influence of typhoon on the one hand, and to the combination of mesoscale vortex on the other hand. In the center of typhoon, the decrease of sea surface salinity is the result of evaporation, turbulent mixing of surface seawater and the competition between water upwelling and precipitation dilution. In addition, a typhoon wind field model is used to calculate the rising distance of water caused by Ekman suction, and the distance of upwelling in the vortex is estimated from the typical upwelling velocity in the vortex. The two values are consistent with the rising distance of the water reflected by the buoy profile. It is explained that the variation of temperature and salinity at the same depth below thermocline is caused by the rise of water body. Then the effects of 15 superstrong typhoons over 20 vortex regions in 2001-2008 on these vortices are analyzed statistically. The aim of this paper is to find out the key factors that influence the variation of ocean vortex. Only two of the 20 vortex regions have new ocean vortex after typhoon, which indicates that typhoon can not induce new ocean vortex in most cases. Through linear regression analysis of three typhoon parameters and six variables describing vorticity variation, it is found that forced time has the best correlation with these six parameters, which is due to the combination of typhoon intensity, typhoon scale and moving velocity. The forced time can be used as an indicator of vorticity change. On the other hand, there are few examples that satisfy the conditions in statistics, which indicates whether the influence of typhoon on the mesoscale vortex of the ocean may need further study. Finally, using the typhoon wind field model and sea surface height and sea surface velocity data, the energy dissipation from typhoon input to current, ocean wave, upper ocean, deep ocean and friction through sea surface is analyzed. By analyzing the work done by typhoon "Pibian" on the study area, it is shown that the typhoon does not do positive work on the current at every point in the vortex when it passes, and whether the typhoon does positive or negative work on the current is fundamentally determined by its relative position with the vortex. The magnitude of typhoon power to current, wave power and friction dissipation through sea surface are 1O-1W / M2100W / M2101W / m2. The power and energy dissipation of sea surface friction is similar to the work power and work diagram of ocean waves. Where the dissipative power and energy are larger, the wind speed is larger, the maximum power is more than 50 W / m ~ 2, and the dissipated energy is 1 OMJ / M ~ (2). In addition, from 2001 to 2012, the energy input to the deep and surface layers was found to be more than 40 KJ / m ~ (2) when the typhoon passed with a high frequency. These sea typhoons are the key areas where energy is pumped into the deep ocean.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P732;P444

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