The downward influence of sudden stratospheric warmings: Association with tropospheric precursors

Ian White, Chaim I. Garfinkel, Edwin Gerber, Martin Jucker, Valentina Aquila, Luke D. Oman

Research output: Contribution to journalArticle

Abstract

Tropospheric features preceding sudden stratospheric warming events (SSWs) are identified using a large compendium of events obtained from a chemistry-climate model. In agreement with recent observational studies, it is found that approximately one-third of SSWs are preceded by extreme episodes of wave activity in the lower troposphere. The relationship becomes stronger in the lower stratosphere, where 60% of SSWs are preceded by extreme wave activity at 100 hPa. Additional analysis characterizes events that do or do not appear to subsequently impact the troposphere, referred to as downward and non-downward propagating SSWs, respectively. On average, tropospheric wave activity is larger preceding downward-propagating SSWs compared to non-downward propagating events, and associated in particular with a doubly strengthened Siberian high. Of the SSWs that were preceded by extreme lower-tropospheric wave activity, 2/3 propagated down to the troposphere, and hence the presence of extreme lower-tropospheric wave activity can only be used probabilistically to predict a slight increase or decrease at the onset, of the likelihood of tropospheric impacts to follow. However, a large number of downward and non-downward propagating SSWs must be considered ( > 35), before the difference becomes statistically significant. The precursors are also robust upon comparison with composites consisting of randomly selected tropospheric northern annular mode (NAM) events. The downward influence and precursors to split and displacement events are also examined. It is found that anomalous upward wave-1 fluxes precede both cases. Splits exhibit a near instantaneous, barotropic response in the stratosphere and troposphere, while displacements have a stronger long-term influence.

Original languageEnglish (US)
Pages (from-to)85-108
Number of pages24
JournalJournal of Climate
Volume32
Issue number1
DOIs
StatePublished - Jan 1 2019

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troposphere
stratosphere
Arctic Oscillation
sudden stratospheric warming
climate modeling

ASJC Scopus subject areas

  • Atmospheric Science

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The downward influence of sudden stratospheric warmings : Association with tropospheric precursors. / White, Ian; Garfinkel, Chaim I.; Gerber, Edwin; Jucker, Martin; Aquila, Valentina; Oman, Luke D.

In: Journal of Climate, Vol. 32, No. 1, 01.01.2019, p. 85-108.

Research output: Contribution to journalArticle

White, Ian ; Garfinkel, Chaim I. ; Gerber, Edwin ; Jucker, Martin ; Aquila, Valentina ; Oman, Luke D. / The downward influence of sudden stratospheric warmings : Association with tropospheric precursors. In: Journal of Climate. 2019 ; Vol. 32, No. 1. pp. 85-108.
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