On the anomalous development of the extremely intense positive Arctic Oscillation of the 2019–2020 winterстатья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 4 июня 2021 г.
Аннотация:AbstractNumerous extreme climate anomalies were recorded in the northern extratropics inJanuary–March (JFM) 2020, significantly impacting human lives and ecosystems in the affectedareas. Those anomalies were caused by an extreme positive Arctic Oscillation (AO) event, with theJFM 2020 AO index of 2.8 being the highest on the record. However, all well-established autumnprecursors pointed towards the following wintertime AO phase being negative. Indeed, a negativeAO phase was developing until late December when a sudden shift to the strong positive AO eventoccurred in the troposphere. The geopotential anomalies associated with positive AO spread intothe lower stratosphere, and were steadily enhancing throughout JFM resulting in an extremepositive AO event. We show that the strong positive AO event was a result of the destructiveinterference of the anomalous planetary waves with climatological ones, which led to waveflattening and enhancement of the polar vortex.