北太平洋冬季西部发展型天气尺度涡旋对平均流的影响
投稿时间: 2017-06-22  最后修改时间: 2017-09-07  点此下载全文
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作者单位E-mail
刘丽 解放军理工大学气象海洋学院 lilynuist@163.com 
谭言科 解放军理工大学气象海洋学院 polaristan@163.com 
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:在中纬度北太平洋大气强斜压区,存在频繁的天气尺度涡旋活动,这种频繁的天气尺度涡旋波活动通过水分、动量和能量输送维持着大气环流。为了进一步理解天气尺度涡旋发生发展与大尺度环流之间的联系,本文利用1981-2013年的再分析资料,挑选西部发展型天气尺度涡旋114个偏强日和87个偏弱日,给出了西部发展型天气尺度涡旋异常导致的动力和热力强迫的变化,同时从能量转换的角度分析了西部发展型天气尺度涡旋与平均流之间的相互作用,并探讨了其与WP遥相关型的关系。结果表明:西部发展型天气尺度涡旋通过动力强迫和热力强迫影响平均流,其中动力强迫主要造成北太平洋中纬度上空的西风气流加速并向北移动;热力强迫的作用则是减弱中纬度大气斜压性。同时,强西部发展型天气尺度涡旋有利于西北太平洋上空对流层低层斜压有效位能向扰动动能转化增大和扰动动能向平均流的转化增大,以及有利于中纬度地区对流层高层平均流向扰动动能转化增大。此外,西部发展型天气尺度涡旋通过与平均流的作用,对于西太平洋遥相关型负位相的维持也起到了一定的作用。
中文关键词:天气尺度涡旋 WP型遥相关 动力强迫 热力强迫?
 
The Influence of the Western Developing Pattern Synoptic-Scale Eddy on the Mean Flow over the North Pacific in Wintertime
Abstract:The spread activity of synoptic-scale eddy is frequent in the atmospheric baroclinic zone of the mid-latitude North Pacific, which has important on the maintaining of the atmospheric circulation through the moisture, momentum and energy transport. To further understand the relationship between the development of the synoptic-scale eddy and large-scale circulation, this paper selected 114 strong and 87 weak western developing synoptic-scale eddy(WSE) days by using the reanalysis data from 1981 to 2013, then gave the dynamic and thermal forcing caused by the WSE anomaly. It analyzed the interaction of the WSE and the mean flow from the perspective of energy transformation and the relationship between the WSE and the West-Pacific(WP) teleconnection. The results show that the WSE has effect on the mean flow through the dynamic and thermal forcing. The dynamic forcing could mainly accelerate and move northward westerly over the mid-latitude North Pacific, while the thermal forcing weaken the mid-latitude atmospheric baroclinicity. At the same time, the strong WSE is beneficial to transform the baroclinic available potential energy to the kinetic energy and the kinetic energy to the mean flow in the lower troposphere over the northwestern Pacific, as well as the mean flow to the kinetic energy in the upper troposphere over the mid-latitude area. In addition, the WSE plays a role in the maintenance of the negative WP through the mean flow.
keywords:Synoptic-scale eddy, WP type teleconnection, dynamic forcing, thermal forcing
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