Evaluating the Brewer–Dobson circulation and its responses to ENSO, QBO, and the solar cycle in different reanalyses

Rao, Jian; Yu, YueYue; Guo, Dong; Shi, Chunhua; Chen, Dan; Hu, DingZhu

doi:10.26464/epp2019012

Cited by 21 publications

(24 citation statements)

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“…Many previous studies have reported enhanced occurrence of a weak stratospheric polar vortex during easterly QBO winters than during westerly QBO winters, known as the Holton‐Tan relationship (Holton & Tan, ; Rao, Yu, et al, ; also see Anstey & Shepherd, , and references therein), and this effect is captured in many of the S2S models (Garfinkel et al, ). The QBO mainly impacts the northern winter stratospheric vortex by shifting the subtropical critical line in the lower stratosphere (Holton & Tan, ) and by changing the mean meridional circulation in the stratosphere (Garfinkel et al, ; Rao, Yu, et al, ). However, those results are obtained from monthly or even seasonal mean data, and SSW can also happen during the westerly QBO winter such as in February 2018.…”

Section: Favorable Conditions For the 2019 New Year Ssw Onsetmentioning

confidence: 98%

The 2019 New Year Stratospheric Sudden Warming and Its Real‐Time Predictions in Multiple S2S Models

et al. 2019

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Using multiple data sources, favorable conditions for the 2019 SSW event and its predictive skill from 11 subseasonal to seasonal (S2S) forecast models are explored in this study. This mixed‐type (displacement to split) SSW event occurred under moderate El Niño, easterly quasi‐biennial oscillation (QBO) together with solar minimum, and phases 4–6 of the Madden‐Julian oscillation (MJO). A strong positive PNA formed and developed in the troposphere before this SSW event, which is associated with enhanced and wave‐1‐dominated eddy heat flux. The predictive limit to this SSW onset is beyond 18 days in most S2S models, longer than the average predictive limit in existing literature. This high predictive skill may originate from the favorable initial conditions (QBO, MJO) and boundary conditions (moderate El Niño, solar minimum). Although some difference in the predictability of the 2019 SSW onset is found between models, most models well forecast its onset at a lead time of 18 days. More than 50% of the ensemble members initialized on 13 December forecast the zonal wind reversal, and the anomaly correlation for tropospheric heights during the SSW onset even exceed 0.7 in the multimodel ensemble (MME). In contrast, the predictability of the wave‐3 and wave‐2 pulses after the SSW onset, responsible for the standing split of the stratospheric polar vortex, is low in the forecast MMEs initialized before the SSW onset. It is a challenge for MMEs initialized before the SSW onset to well forecast the vortex splitting and its persistence 10–20 days after the SSW onset.

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Section: Favorable Conditions For the 2019 New Year Ssw Onsetmentioning

confidence: 98%

The 2019 New Year Stratospheric Sudden Warming and Its Real‐Time Predictions in Multiple S2S Models

et al. 2019

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“…For instance, vortex-displacement SSW events are related to the anomalous amplification of wavenumber-1 planetary waves while vortex-splitting SSW events are caused by the anomalous amplification of wavenumber-two planetary waves [6,19,21]. Additionally, many studies have shown that the occurrence of SSW events can be controlled by some external factors, such as the 11-yr solar cycle [22], the Quasi-Biennial Oscillation (QBO) [23][24][25], El Niño-Southern Oscillation [26], Madden-Julian Oscillation [15,27,28], and stratospheric zonal ozone anomalies [29].…”

Section: Introductionmentioning

confidence: 99%

“…Since only one realization of WACCM is used in this study, the robustness of this study will be improved if more realizations are evaluated. The QBO is nudged in the CESM1-WACCM historical run, which is shown to have an impact on the northern winter stratospheric polar vortex [22][23][24][25]. The newer version of CESM-WACCM, CESM2-WACCM, has a spontaneously generated QBO, which might further improve the simulation of SSWs in this model.…”

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confidence: 98%

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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“…The positive correlation between the solar cycle and regional ozone might indicate that the solar cycle can affect the physicochemical reactions of ozone and its product in the atmosphere [55]. During solar maximum, the tropical stratosphere is anomalously warm, which in turn increases the air stability and weakens the tropical upwelling, favoring an increase in ozone in lower latitudes [56,57].…”

Section: Pacific Decadal Oscillationmentioning

confidence: 99%

Interdecadal Variations of the Midlatitude Ozone Valleys in Summer

et al. 2019

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Using the ERA-Interim total column ozone data, the spatial distributions of the long-term mean of the global total ozone in summer are analyzed. The results demonstrate that there are three midlatitude ozone “valleys” on earth—they are centered over the Tibetan Plateau (TIP), the Rocky Mountains (ROM), and the Southwest Pacific (SWP), respectively. The interdecadal variations of the three ozone valleys are positively modulated by the solar radiation, and the TIP ozone’s correlation with the solar radiation gets maximized with a two-year lag. The interdecadal variation of the SWP ozone valley has a significantly negative relationship with the Pacific Decadal Oscillation (PDO) and the South Pacific quadrupole (SPQ). Warm sea surface temperature anomalies (SSTAs) associated with the SPQ strengthen the vertical ascending motion, which dilutes the high concentration ozone at high altitudes. The interdecadal variation of the ROM ozone valley is positively correlated with the PDO, leading by three years. The ROM ozone content is also modulated by SSTAs in the Indian Ocean basin (IOB) by the circumglobal teleconnection (CGT). The observed regional SSTAs can exert a significant impact on the regional and even global circulation, via which the ozone content in midlatitudes also varies.

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Evaluating the Brewer–Dobson circulation and its responses to ENSO, QBO, and the solar cycle in different reanalyses

Cited by 21 publications

References 0 publications

The 2019 New Year Stratospheric Sudden Warming and Its Real‐Time Predictions in Multiple S2S Models

The 2019 New Year Stratospheric Sudden Warming and Its Real‐Time Predictions in Multiple S2S Models

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

Interdecadal Variations of the Midlatitude Ozone Valleys in Summer

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