Combined effect of the QBO and ENSO on the MJO

Sun, Liying; Wang, Hui; Liu, Fei

doi:10.1080/16742834.2019.1588064

Cited by 22 publications

(25 citation statements)

References 31 publications

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“…Also, like ENSO, the QBO could lead to seasonal mean state changes (Zhang and Zhang 2018;Collimore et al 2003;Liess and Geller 2012). Sun et al (2019) found a combined effect of ENSO and QBO on MJO propagation due to changes in the zonal gradients of the seasonal mean background. The possible combined effects of QBO and ENSO on MJO propagation needs further investigation.…”

Section: Introductionmentioning

confidence: 92%

The Roles of Westward-Propagating Waves and the QBO in Limiting MJO Propagation

Huang

Pegion

2022

Journal of Climate

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A recent study categorized the Madden-Julian Oscillation (MJO) during boreal winter season into four types including stand, jump, slow and fast MJO. This study focuses on the stand and jump MJO. Based on whether their convection penetrates the Maritime Continent (MC), stand and jump MJO are seen as non-penetrating (NP) MJO, while the rest two are seen as eastward-penetrating (EP) MJO. Results reveal the relative roles of the westward-propagating wave (WPW), as well as the QBO and ENSO, in limiting MJO propagation. Lack of the premoistening over the southern sea surface of the MC stops NP MJO from penetrating the MC. The active convection of the WPWs hinders the descending branch of the NP MJO circulation and therefore leads to the insufficient meridional advective moistening over the southern sea surface of the MC. The independent convection over the Pacific for jump MJO is influenced by a combined effect of the QBO and ENSO. The tropopause instability induced by MJO is found to significantly decouple from its convection over the Pacific in the QBOW winters than in the QBOE winters. For jump MJO, the independent convection over the central Pacific comes from local WPWs whose amplification and further development into deep convection are correlated to jump MJO’s decoupled tropopause instability. For stand MJO, however, the seasonal-mean La Nina-like cool SST anomalies weaken the WPW activity over the central Pacific and confine WPWs within the western Pacific. Therefore, the decoupled tropopause instability of stand MJO is out phase of WPWs and fails to induce an independent convection over the central Pacific.

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Section: Introductionmentioning

confidence: 92%

The Roles of Westward-Propagating Waves and the QBO in Limiting MJO Propagation

Huang

Pegion

2022

Journal of Climate

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“…Only the climate indices that are statistically significant from RAWS and reanalysis datasets are listed below. The number in parentheses indicates the time lead of the climate index with 0 for no time lag, − 1 for one season ahead (summer), − 2 for two seasons ahead (spring), and − 3 for three seasons ahead (winter of previous year) Previous studies have found that the interaction between QBO and ENSO themselves can also influence the climate variabilities over the North Pacific Ocean, where the QBO effects can be enhanced during La Niña phases and diminished during El Niño phases (Hansen et al 2016;Sun et al 2019;Wei et al 2007). To investigate whether the ENSO-QBO interaction is dominated by a linear interaction or a nonlinear interaction with the activities of DWs (Hansen et al 2016), we conduct a multiple linear regression model analysis using the two climate indices serving as predictor variables and DWI serving as a response variable.…”

Section: Correlation Analysismentioning

confidence: 99%

“…The QBO also shows a strong connection with ENSO, especially in the North Pacific Ocean (Sun et al 2019;Wei et al 2007). Hansen et al (2016) found that the stratospheric equatorial QBO signals extend down to the troposphere over the North Pacific Ocean during the Northern Hemisphere winters only during La Niña but not during El Niño events.…”

Section: Introductionmentioning

confidence: 99%

Climatology of diablo winds in Northern California and their relationships with large-scale climate variabilities

Liu

Chen

et al. 2020

Clim Dyn

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The most destructive wildfires recently in Northern California have been linked to the occurrences of Diablo Winds (DWs). This study investigates the climatology of DWs during September–December 1979–2018, and their relationships with various climate modes using observations and two high-resolution reanalysis datasets. Our finding shows that DWs do not have a long-term trend in terms of the annual total number, total duration, and associated maximum wind speeds of DWs over the past 4 decades. However, their associated minimum relative humidity (RH) has decreased significantly, especially in October, which suggests that the dryness during DWs has become more severe with time, possibly leading to an increased chance of fires, and their destructive potential. We also find that the annual total number and duration of DWs have exhibited an quasi-periodic variation, with intervals ranging from 2 to 4 years. The periodic variability of DWs might be attributed to the teleconnections between DWs and climate oscillations, specifically the El Niño–Southern Oscillation (ENSO) and the quasi-biennial oscillation (QBO), through their modulation of pressure systems near California and the location of the Pacific jet stream. It is suggested that when La Niña and the QBO westerly phases co-occur in the spring, DWs in the following fall and winter tend to occur more frequently, and are associated with more intense high winds and dryness as compared to other springtime QBO and ENSO phases. This relationship may be used to predict the seasonal outlook of DWs.

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“…However, the exact physical process needs to be investigated in more detail using a series of sensitivity tests with numerical models. On the other hand, the MJO propagation during El Niño winters over the MC is controlled by El Niño induced downward motion and, due to the reinforcement of the MJO over the western Pacific, the effect of QBO on the MJO is less on the MJO predictability limit (Sun et al., 2019).…”

Section: Resultsmentioning

confidence: 99%

“…On the contrary, the MJO propagation pattern shown in Figure 3b (La Niña/EQBO) less resembles Wang et al ( 2019) MJO types. During El Niño/EQBO winters (Figure 3a), an MJO originating from the IO is suppressed over the MC, reinforced over the western Pacific (Sun et al, 2019) and propagates faster toward the central Pacific. Compared with El Niño/ EQBO winters, enhanced convection originating from the IO during El Niño/WQBO winters (Figure 3b) is less suppressed over the MC and reinforced over the western Pacific and propagates toward the central Pacific.…”

Section: Resultsmentioning

confidence: 99%

How Long Can the MJO be Predicted During the Combined Phases of ENSO and QBO?

Mengist

Seo

2022

Geophysical Research Letters

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The Madden-Julian Oscillation (MJO; Madden & Julian, 1971, 1972 is the dominant intraseasonal (30-90 days) variability in the tropical atmosphere, and is characterized by eastward propagating (∼2-9 m/s), planetary-scale envelops of tropical convection that are tightly coupled with large-scale circulation. The MJO typically originates in the equatorial Indian Ocean (IO), crosses the Maritime Continent (MC), and dies out in the central Pacific. The MJO has a great impact on global weather and climate variability (Zhang, 2013). As the MJO moves eastward, it interacts with tropical weather and climate phenomena, including the monsoon (

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Combined effect of the QBO and ENSO on the MJO

Cited by 22 publications

References 31 publications

The Roles of Westward-Propagating Waves and the QBO in Limiting MJO Propagation

The Roles of Westward-Propagating Waves and the QBO in Limiting MJO Propagation

Climatology of diablo winds in Northern California and their relationships with large-scale climate variabilities

How Long Can the MJO be Predicted During the Combined Phases of ENSO and QBO?

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