海洋锋区海表风速最小值与气压调整机制

发布时间：2017-12-28 02:28

  本文关键词：海洋锋区海表风速最小值与气压调整机制　出处：《南京信息工程大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 海洋锋 气压调整机制 海表矢量风速 最小值 背景气压场

【摘要】：利用AVHRR、QuickSCAT等高分辨率卫星观测资料和CFSR再分析资料,分析了墨西哥湾流区、东海黑潮锋区、巴西—马尔维纳斯合流区和厄加勒斯回流区等全球主要海洋锋区的大气响应特征,发现在上述海洋锋区普遍存在海表矢量风速最小值现象,并对这一现象的产生条件、形成机制和影响因子进行了探讨。研究指出：夏季(6-8)墨西哥湾流区、6月东海黑潮锋区、全年巴西—马尔维纳斯合流区及厄加勒斯回流区海洋锋附近有明显的矢量风速最小值现象。产生这一现象的条件为：海洋暖(冷)水区对应于大气高(低)压区。其形成机制可用气压调整机制得到解释：上述条件下,海洋锋暖(冷)侧上空之间产生的局地气压梯度与大尺度背景气压梯度方向接近相反,导致锋区附近叠加后的气压梯度最小,海表风速也因此最小。同时,摩擦作用使海表风偏向低压一侧,于是沿锋区走向(跨锋区走向)的风速分量差在暖水区一侧产生气旋性切变涡度(风速辐合),进而造成上升运动和强降水,而该分量差在冷水区一侧则产生相反的大气响应特征。上述大气响应特征在日尺度下依然存在。锋区海表风速最小值现象在年际时间尺度上受海洋锋强度和背景气压场强度的影响。在海洋锋偏强年和背景气压场偏弱年,气压调整机制的结果使得锋区海表风速最小值现象更为明显,海洋锋偏弱年和背景气压场偏强年的情况则相反。锋区海表风速最小值现象虽然具有全球普适性,但其显著性程度也呈现出区域和季节差异。整体而言,该现象在东海黑潮锋区最为显著,在巴西一马尔维纳斯合流区最弱；月尺度上,以6月巴西—马尔维纳斯合流区最为明显,10月墨西哥湾流区最弱。
[Abstract]:Using the AVHRR reanalysis data and QuickSCAT high resolution satellite data and CFSR, analyzes the response of the Mexico Gulf region, the Kuroshio frontal zone, Brazil - Malvinas confluence zone and Agulhas recirculation zone and other major global ocean front region atmospheric characteristics, found in the sea front area common sea surface wind vector and the minimum phenomenon. For this phenomenon, the formation conditions are discussed and the mechanism of impact factor. The research points out: (6-8) the Mexico Gulf region in summer June, the Kuroshio in the East China Sea front zone, the Brazil - Mar Venus confluence phenomenon obviously near the minimum wind velocity vector and Agulhas recirculation zone ocean front. The condition of this phenomenon is that the Ocean warm (cold) water area corresponds to the high (low) pressure area of the atmosphere. The formation mechanism of the pressure adjusting mechanism has been available to explain: the above conditions, the ocean front warm (cold) generated over the side between the local pressure gradient and pressure gradient in the direction of large scale background nearly opposite, led to the near front zone of the superimposed pressure gradient minimum, sea surface wind speed due to the minimum. At the same time, the friction between the sea surface wind toward the low-pressure side, then along the frontal zone towards (to cross frontal) velocity components to generate cyclonic vorticity in the warm water side (wind speed convergence), causing the ascending motion and precipitation, and the component difference in cold water side has the opposite atmospheric response feature. The above atmospheric response features still exist on the diurnal scale. The minimum wind velocity in front sea surface is influenced by the strength of the ocean front and the background pressure field on the interannual time scale. In the weak year of the ocean front and the background pressure field, the result of the air pressure adjustment mechanism makes the phenomenon of the minimum value of the sea surface wind speed in the front area more obvious. Although the minimum value of wind velocity in front sea surface has global universality, its significant degree also shows regional and seasonal differences. Overall, this phenomenon in the East China Sea Kuroshio region is the most significant, in the Brazil Malvinas confluence zone weakest; the month scale, in June the Brazil Malvinas confluence zone is most obvious, in October the Mexico Gulf region.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P732
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本文编号：1344225