The eastward- and westward-traveling 10-day waves with zonal wavenumbers up to 6 from surface to the middle mesosphere during the recent 12 years from 2007 to 2018 are deduced from MERRA-2 data. On the basis of climatology study, the westward-propagating wave with zonal wave number 1 (W1) and eastward-propagating waves with zonal wave numbers 1 (E1) and 2 (E2) are identified as the dominant traveling ones. They are all active at mid- and high-latitudes above the troposphere and display notable month-to-month variations. The W1 and E2 waves are strong in the NH from December to March and in the SH from June to October, respectively, while the E1 wave is active in the SH from August to October and also in the NH from December to February. Further case study on E1 and E2 waves shows that their latitude–altitude structures are dependent on the transmission condition of the background atmosphere. The presence of these two waves in the stratosphere and mesosphere might have originated from the downward-propagating wave excited in the mesosphere by the mean flow instability, the upward-propagating wave from the troposphere, and/or in situ excited wave in the stratosphere. The two eastward waves can exert strong zonal forcing on the mean flow in the stratosphere and mesosphere in specific periods. Compared with E2 wave, the dramatic forcing from the E1 waves is located in the poleward regions.

根据MERRA-2数据推论，在2007年至2018年的最近12年中，从地表到中层中层的纬向波数最多为6的向东和向西移动的10天波。在气候学研究的基础上，确定了纬向波数为1（W1）的向西传播波和纬向波数为1（E1）和2（E2）的向东传播波为主要传播波。它们都在对流层以上的中高纬度地区活跃，并显示出明显的逐月变化。W1和E2波分别在12月至3月的NH和6月至10月的南半球强，而E1波在8月至10月的SH以及在12月至2月的NH中活跃。对E1和E2波的进一步案例研究表明，它们的纬度-高度结构取决于背景大气的传输条件。平流层和中层中这两个波的存在可能是由于平均流不稳定性在中层层中激发的向下传播波，对流层中的向上传播波和/或平流层中的原位激发波引起的。两次东风波可以在特定时期内对平流层和中层中层的平均流量施加强的纬向强迫。与E2波相比，来自E1波的剧烈强迫位于极地区域。平流层和中层中这两个波的存在可能是由于平均流不稳定性在中层层中激发的向下传播波，对流层中的向上传播波和/或平流层中的原位激发波引起的。两次东风波可以在特定时期内对平流层和中层中层的平均流量施加强的纬向强迫。与E2波相比，来自E1波的剧烈强迫位于极地区域。平流层和中层中这两个波的存在可能是由于平均流不稳定性在中层层中激发的向下传播波，对流层中的向上传播波和/或平流层中的原位激发波引起的。两次东风波可以在特定时期内对平流层和中层中层的平均流量施加强的纬向强迫。与E2波相比，来自E1波的剧烈强迫位于极地区域。