大气浮力频率的时空变化及其影响因子分析
投稿时间:2018-10-22  修订日期:2018-12-21  点此下载全文
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作者单位E-mail
杨可心 南京信息工程大学 1409248485@qq.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:浮力频率是天气动力学中的一个重要概念,但长久以来对其在空间分布和时间演变方面还没有足够的研究。本文通过NCEP/NCAR再分析资料的计算,研究了浮力频率的日内变化、逐日变化、年循环、及年际变化。给出了相关的水平分布和垂直剖面,发现浮力频率的分布与纬度和高度、海洋和陆地、山脉和地形分布等有关。通过对其表达式的变换和推导,浮力频率可以表达为温度及上下层温度差的函数。针对不同时间尺度及空间的采样样本,我们用回归方法建立了浮力频率与这两个量的统计关系,结果表明,温度和上下层温度差对浮力频率影响的相对重要性在不同的样本中是有差异的。
中文关键词:浮力频率  空间分布  时间尺度  动力气象  回归分析
 
The temporal and spatial variation of buoyancy frequency in the atmosphere and the impact factor analysis
Abstract:The buoyancy frequency is one of the important parameters in atmospheric dynamics, but not enough investigations have been conducted on its spatial distribution and temporal evolution. We have done computations based on the data from NCEP/NCAR reanalysis, and give the horizontal distribution and vertical profile of this figure in different time scales. We find that the distribution of the buoyancy frequency not only relates to the latitude and height, but the land-sea distribution, mountains and the terrain as also. The definition of the buoyancy frequency can be rewritten as a function which consists of the mean temperature and the temperature difference between two near levels. We build statistical relationships between the buoyancy frequency and these two factors with the regression analysis. The results show that the relative importance of the temperature and temperature difference in buoyancy frequency changes varies regarding to different time scales and spatial position.
keywords:buoyancy frequency  spatial distribution  time scale  dynamic meteorology  regression analysis
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