Predictability of European winter 2016/2017

Dunstone, Nick; Scaife, Adam A.; MacLachlan, Craig; Knight, Jeff; Ineson, Sarah; Smith, Doug; Thornton, Hazel; Gordon, Margaret; McLean, P.; Palin, Erika J.; Hardiman, Steven C.; Walker, Brent

doi:10.1002/asl.868

Cited by 15 publications

(14 citation statements)

References 30 publications

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“…Dunstone et al . () studied the 2016–2017 winter, which was one of the driest on record for Europe (Figure a). They found results for this dry year very similar to our European dry events.…”

Section: Conclusion and Discussionmentioning

confidence: 94%

“…Not only were the heights similar in the North Atlantic–European region, they also found a dipole in tropical precipitation over the equatorial Atlantic indicating a northward shift of the ITCZ (Dunstone et al ., , their figure 5e). The RWS also showed a dipole structure in the tropical Atlantic, with negative anomalies near 15°N and positive anomalies just south of it (Dunstone et al ., , their figure 5f). They also compared 2016–2017 with 1994–1995 where Europe had its wettest winter (Figure a).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…They also compared 2016–2017 with 1994–1995 where Europe had its wettest winter (Figure a). The 1994–1995 anomalies in heights, in tropical Atlantic precipitation and in tropical Atlantic RWSs were opposite in sign to the 2016–2017 winter (Dunstone et al ., , their figure 4), and also in agreement with the results of our wet events. Another recent wet winter for the UK of 2013–2014 also showed tropical Atlantic RWS anomalies similar to 1994–1995 and opposite in sign to 2016–2017 (Knight et al ., , their figure 4).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…Occasional strong ENSO events can also lead to European wet and dry events through forcings and mechanisms which are different from ours. Dunstone et al (2018) studied the 2016-2017 winter, which was one of the driest on record for Europe ( Figure 1a). They found results for this dry year very similar to our European dry events.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…While not many studies have looked at European dry winters, Dunstone et al . () looked at the recently very dry European winter of 2016–2017. They found evidence for a Rossby wave triggered by anomalous tropical Atlantic precipitation and propagating into Europe.…”

Section: Introductionmentioning

confidence: 99%

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Tropical atmospheric drivers of wintertime European precipitation events

Woollings

O’Reilly

et al. 2020

Quart J Royal Meteoro Soc

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From observations, we identify a wave‐like pattern associated with northwestern European seasonal precipitation events. These events are associated with tropical precipitation anomalies, prompting us to investigate if there are any tropical–extratropical teleconnections, in particular the role of tropical anomalies in driving extratropical dynamics through Rossby wave propagation. Using a hierarchy of models from ray tracing to barotropic and baroclinic models, we investigate the Rossby wave mechanism and test potential tropical drivers and yield qualitative results. Using a barotropic model, we identify potential Rossby wave source regions which are consistent between the observations and the model. These regions include the tropical western and eastern Atlantic, the subtropical eastern Atlantic and, to a smaller degree, the subtropical eastern Pacific. Zonal wavenumber 2 and 3 components of the barotropic model responses match well with the observations and ray tracing supports the importance of these components. We use a baroclinic model to investigate the link between the observed Rossby wave source anomalies and the observed tropical precipitation anomalies. The reduced precipitation observed in the tropical Atlantic just north of the Equator can generate some of the observed Rossby wave source anomalies in the tropical Atlantic, while the increased precipitation observed in the tropical eastern Pacific can generate some of the observed Rossby wave source anomalies in the subtropical eastern Pacific. Our results can also be applied to European drought events because of the qualitative linearity in the observations and in our linear methods.

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Section: Conclusion and Discussionmentioning

confidence: 94%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tropical atmospheric drivers of wintertime European precipitation events

Woollings

O’Reilly

et al. 2020

Quart J Royal Meteoro Soc

Self Cite

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Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO

Hardiman

Dunstone

Scaife

et al. 2020

Atmospheric Science Letters

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Northern Europe and the UK experienced an exceptionally warm and wet winter in 2019/20, driven by an anomalously positive North Atlantic Oscillation (NAO). This positive NAO was well forecast by several seasonal forecast systems, suggesting that this winter the NAO was highly predictable at seasonal lead times. A very strong positive Indian Ocean dipole (IOD) event was also observed at the start of winter. Here we use composite analysis and model experiments, to show that the IOD was a key driver of the observed positive NAO. Using model experiments that perturb the Indian Ocean initial conditions, two teleconnection pathways of the IOD to the north Atlantic emerge: a tropospheric teleconnection pathway via a Rossby wave train travelling from the Indian Ocean over the Pacific and Atlantic, and a stratospheric teleconnection pathway via the Aleutian region and the stratospheric polar vortex. These pathways are similar to those for the El Niño Southern Oscillation link to the north Atlantic which are already well documented. The anomalies in the north Atlantic jet stream location and strength, and the associated precipitation anomalies over the UK and northern Europe, as simulated by the model IOD experiments, show remarkable agreement with those forecast and observed.

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Predictability of European Winters 2017/2018 and 2018/2019: Contrasting influences from the Tropics and stratosphere

Knight

Scaife

Bett

et al. 2020

Atmospheric Science Letters

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The European winters of 2017-18 and 2018-19 were not climatically extreme, but both winters had a major sudden stratospheric warming (SSW). In February 2018, an SSW led to an intense cold outbreak across Europe and further spells of cold weather in March. The SSW of January 2019, although well predicted and expected to increase the chance of a cold end to winter, apparently produced little impact. In this study, we examine the performance of the Met Office seasonal prediction system in these winters, and the influences that led to these outcomes. To achieve this latter objective, sets of numerical experiments are performed in which the tropical troposphere and the extratropical stratosphere are relaxed towards their observed state, allowing the influence of each on the North Atlantic-European atmospheric circulation to be identified. Using these experiments, we show that the SSWs had similar impacts in each case, creating a signal of easterly surface wind anomalies in the weeks following the event. In contrast, tropical influences were opposite in the two winters, acting to strengthen the easterly signal at the end of February 2018 and opposing it in January 2019. The different apparent responses to the two events therefore came about largely through tropical tropospheric variability. Furthermore, we highlight the importance of a very strong cycle of the Madden-Julian Oscillation (MJO) in late January and early February 2018 as an important driver for the February 2018 SSW. MJO teleconnections appear to have been critical in creating the large mid-latitude wave 2 amplitude that has been identified as the immediate cause of this event.

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Predictability of European winter 2016/2017

Cited by 15 publications

References 30 publications

Tropical atmospheric drivers of wintertime European precipitation events

Tropical atmospheric drivers of wintertime European precipitation events

Predictability of European winter 2019/20: Indian Ocean dipole impacts on the NAO

Predictability of European Winters 2017/2018 and 2018/2019: Contrasting influences from the Tropics and stratosphere

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