Prospect of increased disruption to the QBO in a changing climate

Anstey, James; Banyard, Timothy P.; Butchart, Neal; Coy, Lawrence; Newman, Paul A.; Osprey, Scott

doi:10.1002/essoar.10503358.3

Cited by 10 publications

(15 citation statements)

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“…As shown in Fig. 4A (gray arrows), the increased extratropical Rossby wave flux into the tropics is an important contributor to the QBO disruptions (17,19). For example, despite the strong westerlies in 2013/14, there was no QBO disruption, likely because the equatorward Rossby wave flux at 10°N and 40 to 90 hPa was only about half of that in 2015/16.…”

Section: Changes In the Waves Related To The Zonal Wind Changesmentioning

confidence: 92%

“…In the case of 2019/20, strong extratropical Rossby wave forcing from the Southern Hemisphere (SH) initiated the QBO disruption ( 19 ) (left panel of Fig. 2C ), but the MRG wave forcing and vertically propagating equatorial Rossby wave forcing became stronger in October 2019 and finally induced the disruption in January 2020 ( 16 ) (right panel of Fig.…”

Section: Introductionmentioning

confidence: 99%

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Role of tropical lower stratosphere winds in quasi-biennial oscillation disruptions

et al. 2022

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In 2016, the westerly quasi-biennial oscillation (WQBO) in the equatorial stratosphere was unprecedentedly disrupted by westward forcing near 40 hPa; this was followed by another disruption in 2020. Strong extratropical Rossby waves propagating toward the tropics were considered the main cause of the disruptions, but why the zonal wind is reversed only in the middle of the WQBO remains unclear. Here, we show that strong westerly winds in the equatorial lower stratosphere (70 to 100 hPa) help to disrupt the WQBO by hindering the wind reversal at its base. They also help equatorial westward waves propagate further upward, increasing the negative forcing at around 40 hPa that drives the QBO disruptions. Tropical westerly winds have been increasing in the past and are projected to increase in a warmer climate. These background wind changes may allow more frequent QBO disruptions in the future, leading to less predictability in atmospheric weather and climate systems.

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Section: Changes In the Waves Related To The Zonal Wind Changesmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Role of tropical lower stratosphere winds in quasi-biennial oscillation disruptions

et al. 2022

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“…The PC representation of the MERRA‐2 QBO from January 1980 through January 2021 (Figure 1) illustrates the generally circular pattern created as the PC components oscillate with time. The 2015 and 2020 QBO disruption events (Anstey et al., 2021; Newman et al., 2016; Osprey et al., 2016; Saunders et al., 2020; Tweedy et al., 2017) are highlighted along with the corresponding prior years. These recently occurring QBO disruptions provide a special forecast challenge.…”

Section: Forecast and Analysis Systemsmentioning

confidence: 99%

Seasonal Prediction of the Quasi‐Biennial Oscillation

et al. 2022

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The ability to forecast the Quasi‐Biennial Oscillation (QBO) was examined using Version 2 of NASA's Global Earth Observing System Subseasonal‐to‐Seasonal (GEOS‐S2S) forecasting system. The vertical and time structure of the QBO was characterized by the principal components of the first two empirical orthogonal functions (EOFs). A set of 9‐month retrospective forecasts was initialized four times each month between 1981 and early 2019. Validation of 1–9 months forecasts from GEOS‐S2S showed that the S2S retrospective QBO forecasts improved skill in predicting the QBO EOF‐based amplitude and phase over a simple QBO phase propagation model at forecast lead times of 1–3 months. Results from an initial assessment of whether more accurate QBO forecasts can improve Northern Hemisphere winter sea level pressure forecasts showed no significant forecast improvement at a 1‐month lead time, indicating the need for improved stratosphere‐troposphere QBO coupling metrics, pathway identification, and QBO modeling. Overall, these results suggest that future improvements in representing the QBO in global models can increase the skill of 1–3 months QBO forecasts and potentially extend useful QBO forecasts beyond 3 months.

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“…In January 2016 and 2020, the anomalous QBO westerlies in the tropical lower stratosphere were unexpectedly interrupted by anomalous QBO easterlies caused by planetary waves propagating from the mid-latitudes toward the equatorial region combined with equatorial convective gravity waves (Osprey et al, 2016;Coy et al, 2017;Kang et al, 2020;Kang and Chun, 2021). There is not yet a clear understanding of how these QBO disruptions are linked to anomalously warm or cold sea surface temperatures (Taguchi, 2010;Schirber, 2015;Dunkerton, 2016;Christiansen et al, 2016;Barton and McCormack, 2017), volcanic aerosols (Kroll et al, 2020;DallaSanta et al, 2021), wildfire smoke (Khaykin et al, 2020;Yu et al, 2021;Peterson et al, 2021) and climate changes (Anstey et al, 2021b). However, recent study based on climate model simulations from phase six of the Coupled Model Intercomparison Project (CMIP6) predicts increased disruption frequencies to the quasi-regular QBO cycle in a changing climate (Osprey et al, 2016;Anstey et al, 2021b).…”

Section: Introductionmentioning

confidence: 99%

“…There is not yet a clear understanding of how these QBO disruptions are linked to anomalously warm or cold sea surface temperatures (Taguchi, 2010;Schirber, 2015;Dunkerton, 2016;Christiansen et al, 2016;Barton and McCormack, 2017), volcanic aerosols (Kroll et al, 2020;DallaSanta et al, 2021), wildfire smoke (Khaykin et al, 2020;Yu et al, 2021;Peterson et al, 2021) and climate changes (Anstey et al, 2021b). However, recent study based on climate model simulations from phase six of the Coupled Model Intercomparison Project (CMIP6) predicts increased disruption frequencies to the quasi-regular QBO cycle in a changing climate (Osprey et al, 2016;Anstey et al, 2021b).…”

Section: Introductionmentioning

confidence: 99%

Stratospheric water vapor and ozone response to different QBO disruption events in 2016 and 2020

Diallo

Ploeger

Hegglin

et al. 2022

Preprint

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The Quasi-Biennial Oscillation (QBO) is a major mode of climate variability with periodically descending westerly and easterly winds in the tropical stratosphere, modulating transport and distributions of key greenhouse gases such as water vapor and ozone. In 2016 and 2020, anomalous QBO easterlies disrupted the QBO's 28-month period previously observed.Here, we quantify the impact of these two QBO disruption events on the Brewer-Dobson circulation, water vapour and ozone using the ERA5 reanalysis and satellite observations, respectively. Both lower stratospheric trace gases decrease globally during the 2015-2016 QBO disruption event, while they only weakly decrease during the 2019-2020 QBO disruption event.These dissimilarities in the circulation anomalous response to the QBO disruption events result from differences in the tropical upwelling caused by anomalous planetary and gravity wave forcing in the lower stratosphere near the equatorward flanks of the subtropical jet. The differences in the response of lower stratospheric water vapor to the 2015-2016 and 2019-2020 QBO disruption events are due to the cold-point temperature differences induced by the Australian wildfire, which moistened the lower stratosphere, therefore, hidding the 2019-2020 QBO disruption impact. Our results highlight the need for a better understanding of the causes of QBO disruption events, their interplay with other climate variability modes, and their impacts on water vapor and ozone in the face of a changing climate.

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Prospect of increased disruption to the QBO in a changing climate

Cited by 10 publications

References 0 publications

Role of tropical lower stratosphere winds in quasi-biennial oscillation disruptions

Role of tropical lower stratosphere winds in quasi-biennial oscillation disruptions

Seasonal Prediction of the Quasi‐Biennial Oscillation

Stratospheric water vapor and ozone response to different QBO disruption events in 2016 and 2020

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