Investigation of the formation of the Polar-night Jet Oscillation and troposphere-stratosphere dynamical coupling

极夜急流振荡（PJO）是由平流层突然变暖（SSW）和涡旋增强（VB）的准周期性发生所引起的一种现象。发现PJO以以下方式发生：行星波从地表传播到平流层的产生受到地表异常压力和地面经向流的强烈控制。特别是当纬向平均经向风偏北时，flassn - palm （E-P）通量的垂直分量有增强的趋势。一般来说，南纬波发生前的地面气压型与北极涛动（AO）正型非常相似。这种行星波在对流层具有较大的振幅，通过波均流相互作用在平流层产生较大的波强迫，产生距平东风。与此同时，极帽向下的残余流和热带地区向上的流动都是由波的活动产生的，更多的e-强迫与SSW的发生相对应。在极帽的高温区域，声波逐渐衰减，振幅逐渐减小。与此同时，高纬异常偏东区通过热风关系与极帽高温区联系在一起，也通过经向环流的活动向平流层下层和地面进行修正。当距平东风到达地面时，地表气压异常表明AO为负型，地面经向风异常转向南风。在这些条件下，地球波在地面的振幅减小，平流层的波活动比正常情况弱。由于平流层中波浪活度的减小，波浪驱动的剩余环流活度变弱，在极帽处产生VI。与VI相关的极帽距平温度和高纬度纬向风与SSW一样随时间下降，并在距平风到达地面时形成AO的正型。这样，初始条件就得到了再现。这表明了像PJO这样的循环现象是如何通过波均流相互作用和经向环流产生的。少

Polar-night Jet Oscillation (PJO) is a phenomenon that is made by the quasi-periodic occurrence of the stratospheric sudden warming (SSW) and the vortex intensification (VB. PJO is found to occur in the follow way: Generation of planetary waves that propagate from the surface to the stratosphere is strongly controlled by anomalous surface pressure as well as meridional flow in the surface. Especially, if zonal-mean meridional winds are northward, vertical component of the Fliassnn-Palm (E-P) flux have a tendency to be enhanced. Generally, surface pressure pattern before the occurrence of the SSW is very similar to the positive pattern of the Arctic Oscillation (AO). Such planetary waves have larger amplitude in the troposphere and they produce larger wave forcing in the stratosphere through wave-mean flow interaction and produce anomalous easterly wind. At the same time, downward residual flow at the polar cap as well as upward flow at the tropics is produced by the activity of the wav … More e-forcing and this just corresponds to the occurrence of the SSW. Such higher temperature area at the polar-cap gradually dasonnds with reducing amplitude. At the same time, anomalous easterly area at high latitude, which is associated with higher temperature area at the polar-cap through thermal wind relationship, also de mends to the lower stratosphere and also to the surface through the activity of the meridional circulation. When anomalous easterly wind reaches the surface, anomalous surface pressure indicates negative pattern of the AO and anomalous meridional wind at the surface shifted to southward wind. From these conditions, amplitude of the planetary waves at the ground is reduced and wave activity in the stratosphere becomes weaker than normal. By such smaller wave activity in the stratosphere, activity of wave driven residual circulation becomes weaker and produces VI at the polar-cap. Anomalous temperature at the polar-cap and zonal wind at high-latitude associated with VI descends with time as in the SSW and creates positive pattern of the AO when anomalous zonal wind reaches the surface. In such a way, initial condition is reproduced. This shows how the cyclic phenomenon like PJO is created through wave-mean flow interaction and the meridional circulation. Less