Biased MJO causing a lack of QBO–MJO connection in multi-model simulations with a nudged QBO
Abstract
Observations suggest that the stratospheric Quasi-biennial Oscillation (QBO) modulates the Madden-Julian Oscillation (MJO) in the tropical troposphere, where the MJO is stronger with a smoother eastward propagation in the boreal winter seasons with a QBO easterly (QBOE) than that with a QBO westerly (QBOW) phase. Such connection is not captured by current climate models through their internally generated QBO and MJO. The QBO initiative (QBOi) phase 2 project included climate models from global modeling centers and conducted simulations with the tropical zonal-mean zonal wind in the model stratosphere nudged towards the observations. This paper investigates the potential connection between the nudged QBO and the internally generated MJO in 12 participating climate models. Results show that the stratospheric QBO and its associated impacts on the upper troposphere and lower stratosphere stability around the equator are realistically represented in all models through the nudging although a smaller amplitude is found for the temperature responses. However, there is no significant connection between the QBO and MJO in any of the participating models. Further diagnostics suggest this likely result from the biases in the internally generated MJO by the models where the simulated MJO convective variation is constantly underestimated so that the intense MJO OLR and precipitation anomalies are inadequately induced. However, the QBOi phase 2 models show no systematic bias in the MJO cloud-radiative feedback strength, with individual models spanning the full range from underestimation to overestimation of the observed values. These findings emphasize the importance of accurate representation of the MJO convective system in capturing the QBO-MJO connection by climate models. This paper also underscores the urgency of new theoretical understandings for the observed QBO-MJO connection.
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BibTeX
@misc{huang2026biased,
title = {{Biased MJO causing a lack of QBO–MJO connection in multi-model simulations with a nudged QBO}},
author = {Kai Huang and Chang-Hyun Park and Seung-Yoon Back and Jorge García-Franco and Hera Kim and Pu Lin and Scott Osprey and Jadwiga Richter and Chih-Chieh Chen and Seok-Woo Son and Shigeo Yoden and Yuna Lim and Neal Butchart and James Anstey and Yoshio Kawatani and Martin Andrews and François Lott and Yixiong Lu and Zhaoyang Chai and Nan Rosenbloom and Qi Tang and Jinbo Xie and Federico Serva and Dong-Chan Hong and Shingo Watanabe and Aleena Jaison and Hiroaki Naoe and Kohei Yoshida},
howpublished = {EGUsphere [preprint]},
year = {2026},
month = jul,
doi = {10.5194/egusphere-2026-3744},
url = {https://hal.science/hal-05842283v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Biased MJO causing a lack of QBO–MJO connection in multi-model simulations with a nudged QBO
AU - Kai Huang
AU - Chang-Hyun Park
AU - Seung-Yoon Back
AU - Jorge García-Franco
AU - Hera Kim
AU - Pu Lin
AU - Scott Osprey
AU - Jadwiga Richter
AU - Chih-Chieh Chen
AU - Seok-Woo Son
AU - Shigeo Yoden
AU - Yuna Lim
AU - Neal Butchart
AU - James Anstey
AU - Yoshio Kawatani
AU - Martin Andrews
AU - François Lott
AU - Yixiong Lu
AU - Zhaoyang Chai
AU - Nan Rosenbloom
AU - Qi Tang
AU - Jinbo Xie
AU - Federico Serva
AU - Dong-Chan Hong
AU - Shingo Watanabe
AU - Aleena Jaison
AU - Hiroaki Naoe
AU - Kohei Yoshida
PY - 2026
DA - 2026/07/10
PB - EGUsphere [preprint]
DO - 10.5194/egusphere-2026-3744
UR - https://hal.science/hal-05842283v1
AB - Observations suggest that the stratospheric Quasi-biennial Oscillation (QBO) modulates the Madden-Julian Oscillation (MJO) in the tropical troposphere, where the MJO is stronger with a smoother eastward propagation in the boreal winter seasons with a QBO easterly (QBOE) than that with a QBO westerly (QBOW) phase. Such connection is not captured by current climate models through their internally generated QBO and MJO. The QBO initiative (QBOi) phase 2 project included climate models from global modeling centers and conducted simulations with the tropical zonal-mean zonal wind in the model stratosphere nudged towards the observations. This paper investigates the potential connection between the nudged QBO and the internally generated MJO in 12 participating climate models. Results show that the stratospheric QBO and its associated impacts on the upper troposphere and lower stratosphere stability around the equator are realistically represented in all models through the nudging although a smaller amplitude is found for the temperature responses. However, there is no significant connection between the QBO and MJO in any of the participating models. Further diagnostics suggest this likely result from the biases in the internally generated MJO by the models where the simulated MJO convective variation is constantly underestimated so that the intense MJO OLR and precipitation anomalies are inadequately induced. However, the QBOi phase 2 models show no systematic bias in the MJO cloud-radiative feedback strength, with individual models spanning the full range from underestimation to overestimation of the observed values. These findings emphasize the importance of accurate representation of the MJO convective system in capturing the QBO-MJO connection by climate models. This paper also underscores the urgency of new theoretical understandings for the observed QBO-MJO connection.
ER -