中层大气是大气波动盛行的区域。这些波动不仅是这里大气扰动的主要形态,伴随其传播的耗散成为作用在背景流场上的动力强迫和作用于环境物质上的湍流混合,影响到了中层大气的各个方面,尤其对一些典型环流结构的形成起着控制作用。简要地回顾了这个研究领域发展的历史。与此同时,利用美国卫星温度探测数据(SABER/TIMED温度数据)考察了平流层(20~70km高度范围)传播性行星波活动的整体性质,给出了他们的空间分布和年变化形式。利用温度标准差(T-SDEV)代表行星波活动的强度,当前研究显示无论在热带外地区或以赤道为中心的热带地区,全年传播性行星波活动都是相当显著的。结合同期定常行星波活动强度分析结果,通过比较说明在热带外地区,传播性波动和定常波动表现出相近的季节活动性;从T-SDEV数值看,在定常波活动达到最强的季节(冬末春初),这两类波动活动的强度达到了相当的程度(TSDEV=12-14K)。当前结果还显示,在定常波活动受到显著抑制的夏季条件下,传播性波动成为平流层行星波活动的主导成分。在赤道地区的分析结果表明传播性波动是这里的控制性波动,并且其活动强度在全年都处在相当稳定的状态;T-SDEV分析结果还给出了一个值得关注的现象,从平流层下部开始(20km高度)逐渐随高度增大(大于2K),但是这种随高度增长的趋势在30km高度左右突然终止;从30km开始直到中间层底部,T-SDEV几乎不随高度变化,这隐含地说明这里的波动处于一种饱和的状态。
The middle atmosphere is characterized by the prevalence of atmospheric waves. The waves predominate the major variability in the area. The waves also play the role of controlling the various key aspects of the middle atmosphere through wave damping in the propagation of waves, e. g. , exerting mechanical drag on mean flow and causing turbulent diffusion on constituent, in particular in shaping the structures of the general circulations. A brief retrospect in the development in these researches is provided at first. Meanwhile, the temperatures collected by a satellite mission (SABER/TIMED) are used to investigate the property of travelling planetary waves (PWs) in the stratospheric portion (20 - 70 kin). In terms of the standard deviation of temperature, the variability of the wave family is observed, and the annual variation and latitude-height distribution of the variability are presented. The travelling waves are found to be prominent both in the low latitudes as well as in the extra-tropical area. As to extra-tropical area, by comparing to the concurrent variability of stationary PWs retrieved by using the same dataset, both the travelling and the stationary waves exhibit clear annual cycle attaining maximal variability in the late-winter and early-spring ( LWES), with T-SDEV of 12 - 14 K. Moreover, during the summer time when the stationary PWs are strongly depressed, travelling PWs are instead to be the predominant perturbations of planetary scale. Estimation results in terms of T-SDEV show that during the yearly course, the travelling PWs are steadily the predominant waves. Among all the features of the waves, the vertical variation of T-SDEV suggests that the waves are subject to be saturated. For example, the T-SDEV increases with height from 20 km to 30 kin, but from 30 km to the bottom of the mesosphere, the feature is replaced by a phenomenon that the T-SDEV exhibits independence of height.