Modulating Effects of Planetary Wave 3 on a Stratospheric Sudden Warming Event in 2005

Shi, Chunhua; Xu, Ting; Guo, Dong; Pan, Zaitao

doi:10.1175/jas-d-16-0065.1

Cited by 26 publications

(21 citation statements)

References 39 publications

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“…Note also that in 2019, the amplitude of k = 2 was below climatology throughout the atmospheric column, while k = 3 was above climatology from the surface to 30 hPa and matched k = 1 amplitudes in the troposphere (see also Figure 3d). While disruptions of the polar vortex have only rarely been linked to k = 3 activity (Shi et al ., 2017), we consider there to be two potential explanations for its presence here. One possibility is that the k = 3 pattern manifested as anomalous Pacific, Atlantic and Ural blocking highs (Figure 4c), in a similar manner to the k = 2 pattern in 2018 (Figure 4a) but with enhanced sinuosity.…”

Section: Resultsmentioning

confidence: 99%

Differences between the 2018 and 2019 stratospheric polar vortex split events

Butler

Lawrence

Lee

et al. 2020

Quart J Royal Meteoro Soc

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Two recent occurrences in February 2018 and January 2019 of a dynamic split in the Northern Hemisphere stratospheric polar vortex are compared in terms of their evolution and predictability. The 2018 split vortex was associated with primarily wavenumber‐2 wave forcing that was not well predicted more than 7–10 days ahead of time, and was followed by persistent coupling to the surface with strong weather impacts. In 2019 the vortex was first displaced by slow wavenumber‐1 amplification into the stratosphere, which was predictable at longer lead times and then split; the surface impacts following the event were weaker. Here we examine the role of large‐scale climate influences, such as the phase of the El Niño–Southern Oscillation, the Quasi‐biennial Oscillation and the Madden–Julian Oscillation, on the wave forcing, surface impacts and predictability of these two events. Linkages between the forecast error in the stratospheric polar vortex winds with the forecast error in the Quasi‐biennial Oscillation and Madden–Julian Oscillation are examined.

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Section: Resultsmentioning

confidence: 99%

Differences between the 2018 and 2019 stratospheric polar vortex split events

Butler

Lawrence

Lee

et al. 2020

Quart J Royal Meteoro Soc

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show abstract

“…As one of the most spectacular and radical phenomena in the atmosphere, stratospheric sudden warming (SSW) events mainly occur in the boreal winter, when the polar vortex deforms and can even break down (Labitzke & van Loon, ; O'Neill, ; Shi et al, ). SSW events are usually accompanied by a rapid increase (up to 50 K) in the polar cap temperature and a weakening and reversal of the circumpolar westerly jet (e.g., Charlton & Polvani, ; Hu et al, ; Limpasuvan et al, ).…”

Section: Introductionmentioning

confidence: 99%

The Stratospheric Sudden Warming Event in February 2018 and its Prediction by a Climate System Model

et al. 2018

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A major stratospheric sudden warming (SSW) event was observed in February 2018 after a 4-year absence since the winter of 2013/2014. Based on the reanalysis data, the polar night jet changed from a very strong state to a moderate state during 12-19 January, and the moderate westerlies directly reversed to easterlies during 5-15 February. The intensified East Asian trough, Alaskan blocking, and East U.S. trough amplified the extratropical climatological wave 2, which propagated upward into the stratosphere, leading to a vortex-splitting SSW event. Predictions of the February 2018 SSW event are explored in hindcasts initialized 0-4 weeks in advance by the Beijing Climate Center Climate System Model. Less than 20% of the 28 ensemble members predict the reversal of [U] 60°N, 10hPa in hindcasts initialized 3 or 4 weeks in advance if a 5-day error is allowed, while this ratio increases to 43% in hindcasts initialized 1 week in advance. Based on the climatological occurrence of SSW events in the forecast system, the maximum deterministic predictable limit of this event is 1-2 weeks in this forecast system. The eddy heat flux and its domination by wave 2 can only be predicted within the predictable time limit. A comparison between hindcast members initialized 2 weeks in advance suggests that the extratropical troughs and blockings are responsible for the upward propagation of waves from the troposphere to the stratosphere. The predictable limit of the stratospheric circulation pattern for the February 2018 SSW, 1-2 weeks, also generalizes to other vortex split SSW events such as the

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“…When SSW events occur, the polar cap temperature suddenly rises and increases by tens of Kelvins within several days. In the meantime, the stratospheric circulation also adjusts: westerlies in the circumpolar region considerably decrease and even reverse the sign to easterlies; the stratospheric cyclone in the high latitudes gradually shifts from the polar region, deforms in its shape, and even breaks up into two sister vortices [3,4]. Since this phenomenon was first detected by Richard Scherhag [5], much work has been done about SSWs, including their theories [6][7][8], classifications [9], effects on surface weather and climate [10][11][12], simulations in models [13][14][15], and predictions [16,17].…”

Section: Introductionmentioning

confidence: 99%

Statistical Characteristics of Major Sudden Stratospheric Warming Events in CESM1-WACCM: A Comparison with the JRA55 and NCEP/NCAR Reanalyses

et al. 2019

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Using the historical simulation from the CESM1-WACCM coupled model and based on the JRA55 and NCEP/NCAR reanalyses, the general statistical characteristics of the major sudden stratospheric warmings (SSWs) in this stratosphere-resolving model are assessed. The statistical and diagnostic results show that CESM1-WACCM can successfully reproduce the frequency of SSW events. As in the JRA55 and NCEP/NCAR reanalyses, five or six SSW events, on average, occur in a model decade. The seasonal distribution of SSWs is also well simulated with the highest frequency in January (35%). The unprecedented low SSW frequency observed in 1990s from the two reanalyses is also identified in a model decade (1930s). In addition, the overestimated duration of SSW events in the earlier WACCM version is not identified in CESM1-WACCM when compared with the two reanalyses. The model can well reproduce the downward propagation of the stratospheric anomaly signals (i.e., zonal wind, height, temperature) following SSWs. Both the modelling and observational evidences indicate that SSWs are proceeded by the positive Pacific–North America (PNA) and negative Western Pacific (WP) pattern. The negative North Atlantic Oscillation (NAO) develops throughout the SSW life cycle, which is successfully modeled. A cold Eurasian continent–warm North American continent pattern is observed before SSWs at 850 h Pa, while the two continents are anomalously cold after SSWs in both the reanalyses and the model.

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Modulating Effects of Planetary Wave 3 on a Stratospheric Sudden Warming Event in 2005

Cited by 26 publications

References 39 publications

Differences between the 2018 and 2019 stratospheric polar vortex split events

Differences between the 2018 and 2019 stratospheric polar vortex split events

The Stratospheric Sudden Warming Event in February 2018 and its Prediction by a Climate System Model

Statistical Characteristics of Major Sudden Stratospheric Warming Events in CESM1-WACCM: A Comparison with the JRA55 and NCEP/NCAR Reanalyses

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