Progress in Simulating the Quasi‐Biennial Oscillation in CMIP Models

Richter, Jadwiga H.; Anstey, James; Butchart, Neal; Kawatani, Yoshio; Meehl, Gerald A.; Osprey, Scott; Simpson, Isla R.

doi:10.1029/2019jd032362

Cited by 82 publications

(110 citation statements)

References 35 publications

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“…Details of the CMIP6 models and experiment can be found on the CMIP website (https://www.wcrp-climate.org/wgcm-cmip/wgcm-cmip6). A total of 30 models from the CMIP6 historical simulation are analyzed based on the availability of data at the time of writing this manuscript, and they are consistent with the models used in Richter et al (2020). Available ensemble members are listed in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…To evaluate model performance in simulating the QBO, time series of monthly mean zonal‐mean zonal wind averaged over 10°S to 10°N (hereafter, [U]) at 50 hPa are compared (Figure 2). A model is considered to simulate the QBO if [U] between 10 and 100 hPa exhibits alternating westerlies and easterlies, and the standard deviation (σ) of the deseasonalized time series is at least 20% of observed at all levels between 10 and 70 hPa (similar to Richter et al, 2020, except they used 5°S to 5°N average to define [U]). This is evaluated with all ensembles, but the existence of the QBO in a model does not depend on ensemble members.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, because the observational record only extends back a few decades, GCMs could be invaluable tools for studying the key mechanism for the QBO‐MJO connection. However, the majority of the last generation of GCMs have been suffering from deficiencies in simulating the characteristics of both the QBO (Butchart et al, 2018; Richter et al, 2020; Schenzinger et al, 2017) and MJO (Ahn et al, 2017), making a further investigation of their interaction a challenging task. One model that has been shown to capture both the QBO and MJO is the Met Office Unified Model, but even so, this model was found to not capture the QBO‐MJO connection (Lee & Klingaman, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…However, to date, only a small number of individual models have been probed for evidence of a QBO‐MJO connection (Lee & Klingaman, 2018). Many of the new state‐of‐the‐art models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6; Eyring et al, 2016) are now capable of simulating an internally generated QBO (Richter et al, 2020). The larger number of CMIP6 models with reasonable QBO provides an unprecedented opportunity to test whether the QBO‐MJO connection is simulated.…”

Section: Introductionmentioning

confidence: 99%

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The Lack of QBO‐MJO Connection in CMIP6 Models

Kim

Caron

Richter

et al. 2020

Geophysical Research Letters

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Observational analysis has indicated a strong connection between the stratospheric quasi‐biennial oscillation (QBO) and tropospheric Madden‐Julian oscillation (MJO), with MJO activity being stronger during the easterly phase than the westerly phase of the QBO. We assess the representation of this QBO‐MJO connection in 30 models participating in the Coupled Model Intercomparison Project 6. While some models reasonably simulate the QBO during boreal winter, none of them capture a difference in MJO activity between easterly and westerly QBO that is larger than that which would be expected from the random sampling of internal variability. The weak signal of the simulated QBO‐MJO connection may be due to the weaker amplitude of the QBO than observed, especially between 100 to 50 hPa. This weaker amplitude in the models is seen both in the QBO‐related zonal wind and temperature, the latter of which is thought to be critical for destabilizing tropical convection.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Lack of QBO‐MJO Connection in CMIP6 Models

Kim

Caron

Richter

et al. 2020

Geophysical Research Letters

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“…All six of these models represent the Quasi-Biennial Oscillation (QBO) (Rao et al, 2020;Richter et al, 2020).…”

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confidence: 99%

Influence of ENSO on entry stratospheric water vapor in coupled chemistry-ocean CCMI and CMIP6 models

Garfinkel

Harari

Ziskin

et al. 2020

Preprint

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Abstract. The connection between the dominant mode of interannual variability in the tropical troposphere, El Nino Southern Oscillation (ENSO), and entry of stratospheric water vapor, is analyzed in a set of the model simulations archived for the Chemistry-Climate Model Initiative (CCMI) project and for phase 6 of the Coupled Model Intercomparison Project. While the models agree on the temperature response to ENSO in the tropical troposphere and lower stratosphere, and all models also agree on the zonal structure of the response in the tropical tropopause layer, the only aspect of the entry water vapor with consensus is that La Nina leads to moistening in winter relative to neutral ENSO. For El Nino and for other seasons there are significant differences among the models. For example, some models find that the enhanced water vapor for La Nina in the winter of the event reverses in spring and summer, other models find that this moistening persists, while some show a nonlinear response with both El Nino and La Nina leading to enhanced water vapor in both winter, spring, and summer. Focusing on Central Pacific ENSO versus East Pacific ENSO, or temperatures in the mid-troposphere as compared to temperatures near the surface, does not narrow the inter-model discrepancies. Despite this diversity in response, the temperature response near the cold point can explain the response of water vapor when each model is considered separately. While the observational record is too short to fully constrain the response to ENSO, it is clear that most models suffer from biases in the magnitude of interannual variability of entry water vapor. This bias could be due to missing forcing processes that contribute to observed variability in cold point temperatures.

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Effect of quasi‐biennial oscillation on the intensity of the South China Sea summer monsoon

Hu,

Jian,

Gao

2023

Intl Journal of Climatology

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The interannual relationship between the quasi‐biennial oscillation (QBO) and the South China Sea (SCS) summer monsoon intensity (SCSSMI) is investigated using the ERA5 data set in the period of 1953–2020. The QBO–SCSSMI connection is weak in El Niño‐Southern Oscillation (ENSO)‐related summer, but significant in neutral ENSO summer. In neutral ENSO summer, there is significant positive correlation between QBO and SCSSMI, that is, the SCSSMI is enhanced in the QBO westerly phase, while it is weakened in the QBO easterly phase with larger amplitude of the SCSSMI anomaly. QBO may modulate the SCSSMI in three possible ways. The QBO‐related temperature anomalies downward to the lower stratosphere directly affect the SCS monsoon convection by modulating the upper‐tropospheric stability and tropopause height over the SCS region. Moreover, the QBO‐related anomalous zonal wind downward to the lower stratosphere may regulate cross‐tropopause vertical wind shear and then modulate the convection development. Besides, the QBO‐related zonal wind and temperature signals propagating downward into the upper troposphere can affect the horizontal divergence by influencing the vertical vorticity and the geopotential via thermal forcing. Through those three processes, QBO directly affects the deep convection activities and then modulates the SCSSMI via internal dynamic adjustment. In the southern SCS, cross‐tropopause vertical wind shear makes a main contribution to deep convections, while upper‐tropospheric static stability makes a major contribution to deep convection in the northern SCS. The conclusions are also generally verified by the CMIP6 model simulation.

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Progress in Simulating the Quasi‐Biennial Oscillation in CMIP Models

Cited by 82 publications

References 35 publications

The Lack of QBO‐MJO Connection in CMIP6 Models

The Lack of QBO‐MJO Connection in CMIP6 Models

Influence of ENSO on entry stratospheric water vapor in coupled chemistry-ocean CCMI and CMIP6 models

Effect of quasi‐biennial oscillation on the intensity of the South China Sea summer monsoon

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