The Northern Hemisphere (NH) polar winter stratosphere of 2019/2020 featured an exceptionally strong and cold stratospheric polar vortex. Wave activity from the troposphere during December–February was unusually low, which allowed the polar vortex to remain relatively undisturbed. Several transient wave pulses nonetheless served to help create a reflective configuration of the stratospheric circulation by disturbing the vortex in the upper stratosphere. Subsequently, multiple downward wave coupling events took place, which aided in dynamically cooling and strengthening the polar vortex. The persistent strength of the stratospheric polar vortex was accompanied by an unprecedentedly positive phase of the Arctic Oscillation in the troposphere during January–March, which was consistent with large portions of observed surface temperature and precipitation anomalies during the season. Similarly, conditions within the strong polar vortex were ripe for allowing substantial ozone loss: The undisturbed vortex was a strong transport barrier, and temperatures were low enough to form polar stratospheric clouds for over 4 months into late March. Total column ozone amounts in the NH polar cap decreased and were the lowest ever observed in the February–April period. The unique confluence of conditions and multiple broken records makes the 2019/2020 winter and early spring a particularly extreme example of two‐way coupling between the troposphere and stratosphere.

中文翻译：

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2020年冬季极强的北极平流层极涡：与破纪录的北极涛动和臭氧损失有关

2019/2020年的北半球极地平流层具有异常强和冷的平流层极涡。在12月至2月期间，对流层的波活动异常低，这使极地涡旋保持相对不受干扰。尽管如此，仍有几个瞬变波脉冲通过扰动高空平流层中的涡旋来帮助形成平流层环流的反射构造。随后，发生了多个向下波耦合事件，这有助于动态冷却和增强极地涡旋。在1月至3月期间，平流层极涡的持续强度伴随着对流层中北极涛动的空前正相，这与整个季节观测到的大部分地表温度和降水异常一致。同样，强极性涡流内的条件已经成熟，足以使臭氧​​大量流失：不受干扰的涡流是很强的运输屏障，并且温度低到足以形成极地平流层云，历时4个月，直到3月底。NH极极柱中的总色谱柱臭氧量下降，并且是2月至4月期间观察到的最低值。独特的条件融合和多次破记录使2019/2020年冬季和初春成为对流层与平流层之间双向耦合的一个极端例子。不受干扰的涡旋是很强的传输屏障，并且自3月底以来的4个月中，温度低到足以形成极地平流层云。NH极极柱中的总色谱柱臭氧量下降，并且是2月至4月期间观察到的最低值。独特的条件融合和多次破记录使2019/2020年冬季和初春成为对流层与平流层之间双向耦合的一个极端例子。不受干扰的涡旋是很强的传输屏障，并且自3月底以来的4个月中，温度低到足以形成极地平流层云。NH极极柱中的总色谱柱臭氧量下降，并且是2月至4月期间观察到的最低值。独特的条件融合和多次破记录使2019/2020年冬季和初春成为对流层与平流层之间双向耦合的一个极端例子。