Modulation of the MJO and North Pacific Storm Track Relationship by the QBO

Wang, Jiabao; Kim, Hye‐Mi; Chang, Edmund K. M.; Son, Seok‐Woo

doi:10.1029/2017jd027977

Cited by 45 publications

(47 citation statements)

References 74 publications

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“…The CESM simulation results also show similar stronger poleward Plumb flux transport over Eurasia in February during EQBO phases (Figure d), although this phenomenon is not quite the same in January (Figure c). The enhanced poleward propagation of synoptic‐scale waves in late winter might be related to the poleward shift of the subtropical jet during EQBO phases (i.e., positive wind contour lines to the north of 30°N over Asia in Figure and positive zonal wind anomalies to the north of 30°N in Figure ), which is in agreement with previous findings (Lachmy & Harnik, ; Wang et al, ; White et al, ).…”

Section: Mechanisms Responsible For Qbo‐induced Polar Vortex Shiftmentioning

confidence: 99%

Seasonal Evolution of the Quasi‐biennial Oscillation Impact on the Northern Hemisphere Polar Vortex in Winter

Zhang

Xie

et al. 2019

JGR Atmospheres

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Using potential vorticity to define Northern Hemisphere (NH) stratospheric polar vortex strength and position, the influence of the QBO on the polar vortex in winter is analyzed. The results show that the weakened/enhanced NH polar vortex in the lower stratosphere during easterly/westerly QBO (E/WQBO) phases is more noticeable in January and February than in November and December. Furthermore, the NH polar vortex shows a shift toward the Eurasian continent and away from North America in winter during EQBO phases compared with that during WQBO phases, with a greater shift in January and February than in November and December. The weaker QBO impact on the zonal mean zonal wind and temperature in February found in previous studies may be related to the cancelling effects of opposite‐signed anomalies over Eurasia and North America induced by the polar vortex shift associated with the QBO. During EQBO phases the upper stratospheric easterly anomalies in early winter increase the frequency of negative refractive index in the middle and high latitudes in late winter. Less planetary wave 1 propagates upward into the upper stratosphere and more wave 1 accumulates in the lower stratosphere, leading to the weakening and shift of the polar vortex in late winter. In addition, the poleward displacement of the subtropical jet during EQBO phases causes more poleward propagation of synoptic‐scale waves in the lower stratosphere, and thus more Rossby wave breaking events over Eurasia in late winter than during WQBO phases, further weakening and shifting the polar vortex in EQBO phases.

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Section: Mechanisms Responsible For Qbo‐induced Polar Vortex Shiftmentioning

confidence: 99%

Seasonal Evolution of the Quasi‐biennial Oscillation Impact on the Northern Hemisphere Polar Vortex in Winter

Zhang

Xie

et al. 2019

JGR Atmospheres

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“…In westerly QBO, more planetary waves propagate into the tropics, and the poleward propagation is weaker, leading to a stronger polar vortex [27,34,35]. Both the MJO and the QBO can influence the atmospheric rivers, mid-latitude storm track, and extratropical climate [36][37][38][39].A recent study by Feng and Lin [40] indicated that the North Atlantic Oscillation (NAO) and the MJO connection can be modulated by the QBO. The positive NAO follows the MJO convection over the tropical Indian Ocean, and negative NAO is led by the MJO convection over the western Pacific [41,42].…”

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confidence: 99%

Modulation of the Westerly and Easterly Quasi-Biennial Oscillation Phases on the Connection between the Madden–Julian Oscillation and the Arctic Oscillation

Song

2020

Atmosphere

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Previous studies have revealed the relationship between the Madden-Julian oscillation (MJO) and the Arctic Oscillation (AO). The MJO phase 2/3 is followed by the positive AO phase, and the MJO phase 6/7 is followed by the negative AO phase. This study reveals that the MJO phase 6/7-AO connection is modulated by the Quasi-Biennial Oscillation (QBO) through both tropospheric and stratospheric pathways during boreal winter. The MJO 2/3 phase and AO relationship is favored in both QBO easterly (QBOE) and westerly (QBOW) years because of the MJO-triggered tropospheric Rossby wave train from the tropics toward the polar region. The AO following the MJO 6/7 phase shifts to negative in QBOW years, but the MJO-AO connection diminishes in QBOE years. In QBOW years, the Asian-Pacific jet is enhanced, leading to more evident poleward propagation of tropospheric Rossby wave train, which contributes to the tropospheric pathway of the AO-MJO 6/7 connection. Besides, the enhanced Asian-Pacific jet in QBOW years is favorable for vertical propagation of planetary waves into the stratosphere in MJO phase 6/7, leading to negative AO, which indicates the stratospheric pathway of the AO-MJO 6/7 connection.Atmosphere 2020, 11, 175 2 of 13 response [17,18] that propagates poleward and eastward and modulates the atmospheric Pacific-North America (PNA)-like teleconnection pattern [19] over the North Pacific and North Atlantic. The MJO can also influence the AO [12]. The MJO can also modify the meridional heat flux that is in phase with climatological stationary waves over the North Pacific, which interferes constructively with climatological stationary waves and induces vertical propagation of planetary waves into the stratosphere, contributing to the polar vortex variation [20][21][22][23]. The anomalous signal of the stratospheric polar vortex propagates downward and influences the tropospheric AO [24].Both the MJO and the AO are associated with the Quasi-Biennial Oscillation (QBO), which manifests as alternating easterly and westerly zonal winds over the stratospheric tropics on the time scale of 2.5 years [25][26][27]. During boreal winter, about 40% of the interannual variation of the MJO is contributed by the QBO [28][29][30]. The strength of the MJO can be influenced by the QBO, and thus the MJO-related teleconnection changes in QBO easterly and westerly years [29]. The MJO tends to be stronger in the easterly wind phase of the QBO (QBOE) than the westerly wind phase of the QBO (QBOW), which may be attributed to the change in the static stability at the tropopause caused by the [31][32][33]. The QBO can be linked to the stratospheric polar vortex through upward propagation of planetary waves and the interaction between the stratospheric zonal mean zonal wind and the planetary waves [27]. The variation of the stratospheric polar vortex can influence the AO by downward propagation of stratospheric anomalous signals [24]. The zero-wind line at 50 hPa differs in the easterly and westerly QBO phases, which leads to a difference in the u...

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“…Such wave propagation typically occurs over the North Pacific (Figures a–d). Although this wave train is sensitive to the QBO (Son et al, ; Wang et al, ), its difference between EQBO and WQBO winters is mainly observed around the date line far downstream of the continent. This location may imply that the differences in precipitation anomalies (Figure and Table ) are mostly due to changes in the Rossby gyres response over the continent rather than to the wave train in the North Pacific modulated directly by the QBO.…”

Section: Resultsmentioning

confidence: 99%

“…Through this wave train, the MJO generates anomalous circulation in the extratropics that resembles the Pacific/North American pattern (Wallace & Gutzler, ; Zhang, ). This affects surface weather in the northern extratropics, including East Asia (EA; Jeong et al, ; Seo et al, ; Wang et al, ), North America (Bond & Vecchi, ), Europe (Seo et al, ), and even the Arctic (Yoo et al, ). Given this teleconnection, the MJO is considered as one of the key sources for subseasonal prediction in the extratropics (Vitart & Robertson, ).…”

Section: Introductionmentioning

confidence: 99%

“…A strengthened MJO convection, which occurs when the tropical zonal wind at 50 hPa is easterly (the easterly QBO phase; EQBO), leads to a more organized MJO teleconnection in the upper troposphere (Son et al, ) and lower stratosphere (Liu et al, ). Among others, Wang et al () showed that the QBO‐induced MJO teleconnection change is also evident in North Pacific storm tracks. They further documented that such a change is likely caused not only by changes in the MJO amplitude but also by changes in background flow.…”

Section: Introductionmentioning

confidence: 99%

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QBO Modulation of the MJO‐Related Precipitation in East Asia

2020

Self Cite

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This study revisits precipitation change in East Asia caused by the Madden‐Julian oscillation (MJO) and its interannual variation due to the quasi‐biennial oscillation (QBO). Specifically, boreal‐winter precipitation, derived from weather stations across China, Korea, and Japan, is examined for MJO phases 2–3 and 6–8. Consistent with previous findings, precipitation in southern China and southern Japan increases by up to 36% during MJO phases 2–3, when the MJO convection is located in the Indian Ocean. In contrast, during MJO phases 6–8, precipitation decreases by 13%. More importantly, these MJO‐related precipitation anomalies become larger and more organized when the QBO is in its easterly phase. The difference in precipitation anomalies between the QBO easterly and westerly phases is approximately 40% for MJO phases 2–3 and 70% for MJO phases 6–8 from southern China to Japan. This result reaffirms that the QBO can affect surface weather in the northern extratropics through MJO teleconnection.

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Modulation of the MJO and North Pacific Storm Track Relationship by the QBO

Cited by 45 publications

References 74 publications

Seasonal Evolution of the Quasi‐biennial Oscillation Impact on the Northern Hemisphere Polar Vortex in Winter

Seasonal Evolution of the Quasi‐biennial Oscillation Impact on the Northern Hemisphere Polar Vortex in Winter

Modulation of the Westerly and Easterly Quasi-Biennial Oscillation Phases on the Connection between the Madden–Julian Oscillation and the Arctic Oscillation

QBO Modulation of the MJO‐Related Precipitation in East Asia

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