Skilful predictions of the Summer North Atlantic Oscillation

Dunstone, Nick; Smith, Doug M.; Hardiman, Steven C.; Hermanson, Leon; Ineson, Sarah; Kay, Gillian; Li, Chaofan; Lockwood, Julia F.; Scaife, Adam A.; Thornton, Hazel; Ting, Mingfang; Wang, Lei

doi:10.1038/s43247-023-01063-2

Cited by 8 publications

(2 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have, however, shown that there is a predicted signal in summer circulation for the UK, and the fact that other studies have noted poor circulation skill in summer in similar regions over different time periods (e.g. Dunstone et al ., 2018, 2023), hints that examining the predictability of summer Rossby wave propagation may hold the key to improving summer seasonal predictions for the UK and other areas of northern Europe.…”

Section: Resultsmentioning

confidence: 99%

Seasonal prediction of UK mean and extreme winds

Lockwood,

Stringer,

Hodge

et al. 2023

Quart J Royal Meteoro Soc

Self Cite

View full text Add to dashboard Cite

Recent studies have shown that seasonal forecasting systems have significant skill in predicting northern European winds and storms in winter, but other seasons have not been so extensively analysed. Given this fact, and coupled with requests from users of the Met Office 3‐month outlook for the United Kingdom (UK), we have investigated the skill in predicting seasonal (3‐month) mean UK wind speed and storms (extreme winds) with a one‐month lead‐time, throughout the year, using a large ensemble from the Met Office's seasonal prediction system, GloSea. We find that seasonal UK storms and mean wind speeds are well correlated, and therefore a single prediction of UK mean wind speed will give an indication of predicted storm counts. Skill for these predictions is highest in winter (December–February), related to predictability of the North Atlantic Oscillation. In contrast, summer (June–August) UK wind skill is not significant and furthermore appears to be negative. We find evidence, in both observations and model members, for a Rossby wave from the tropics influencing UK summer winds and forming a significant predictable component in the model ensemble mean. However, the model predictable signal appears to be out of phase with that observed leading to the negative correlation. Further investigation into summer Rossby wave generation and propagation is necessary to understand whether summer predictions could be improved.

show abstract

Section: Resultsmentioning

confidence: 99%

Seasonal prediction of UK mean and extreme winds

Lockwood,

Stringer,

Hodge

et al. 2023

Quart J Royal Meteoro Soc

Self Cite

View full text Add to dashboard Cite

show abstract

“…While the signal-tonoise paradox was initially identified for the winter season in the North Atlantic, similar though weaker findings have been suggested for parts of the Pacific and for predictions of the Southern Annular Mode. New studies have shown evidence that it also occurs for summer precipitation over Northern Europe, the NAO, and the Tibetan Plateau (Dunstone et al, 2018;Yeager et al, 2018;Hu & Zhou, 2021;Dunstone et al 2023), and in the autumn season East Atlantic pattern (Thornton et al, 2023).…”

Section: Disentangling Forced Response From Internal Variabilitymentioning

confidence: 99%

Detected climate change signals in atmospheric circulation: mechanisms, puzzles and opportunities

Shaw,

Arblaster,

Birner

et al. 2024

Preprint

View full text Add to dashboard Cite

The circulation response to climate change shapes regional climate and extremes. We have moved into a new era where circulation signals have been detected across many regions and seasons. The detected circulation signals represent an exciting opportunity for improving our understanding of dynamical mechanisms, testing our theories and reducing uncertainties. They have also presented some puzzles that represent an opportunity for better understanding the circulation response, its contribution to climate extremes, interactions with cloud feedbacks, and connection to thermodynamic discrepancies. The next decade or so is likely to be a golden age for dynamics with many advances possible.

show abstract

A hypothesis on ergodicity and the signal‐to‐noise paradox

Brener

2024

Atmospheric Science Letters

View full text Add to dashboard Cite

This letter raises the possibility that ergodicity concerns might have some bearing on the signal‐to‐noise paradox. This is explored by applying the ergodic theorem to the theory behind ensemble weather forecasting and the ensemble mean. Using the ensemble mean as our best forecast of observations amounts to interpreting it as the most likely phase‐space trajectory, which relies on the ergodic theorem. This can fail for ensemble forecasting systems if members are not perfectly exchangeable with each other, the averaging window is too short and/or there are too few members. We argue these failures can occur in cases such as the winter North Atlantic Oscillation (NAO) forecasts due to intransitivity or regime behaviour for regions such as the North Atlantic and Arctic. This behaviour, where different ensemble members may become stuck in different relatively persistent flow states (intransitivity) or multi‐modality (regime behaviour), can in certain situations break the ergodic theorem. The problem of non‐ergodic systems and models in the case of weather forecasting is discussed, as are potential mitigation methods and metrics for ergodicity in ensemble systems.

show abstract

Skilful predictions of the Summer North Atlantic Oscillation

Cited by 8 publications

References 60 publications

Seasonal prediction of UK mean and extreme winds

Seasonal prediction of UK mean and extreme winds

Detected climate change signals in atmospheric circulation: mechanisms, puzzles and opportunities

A hypothesis on ergodicity and the signal‐to‐noise paradox

Contact Info

Product

Resources

About