Multidecadal variations of the effects of the Quasi-Biennial Oscillation on the climate system

Brönnimann, Stefan; Malik, Abdul; Stickler, Alexander; Wegmann, Martin; Raible, Christoph; Muthers, Stefan; Anet, Julien; Rozanov, Eugene; Schmutz, Werner (2016). Multidecadal variations of the effects of the Quasi-Biennial Oscillation on the climate system. Atmospheric chemistry and physics, 16(24), pp. 15529-15543. European Geosciences Union 10.5194/acp-16-15529-2016

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Effects of the Quasi-Biennial Oscillation (QBO) on tropospheric climate are not always strong or they appear only intermittently. Studying them requires long time series of both the QBO and climate variables, which has restricted previous studies to the past 30–50 years. Here we use the benefits of an existing QBO reconstruction back to 1908. We first investigate additional, newly digitized historical observations of stratospheric winds to test the reconstruction. Then we use the QBO time series to analyse atmospheric data sets (reconstructions and reanalyses) as well as the results of coupled ocean–atmosphere–chemistry climate model simulations that were forced with the reconstructed QBO. We investigate effects related to (1) tropical–extratropical interaction in the stratosphere, wave–mean flow interaction and subsequent downward propagation, and (2) interaction between deep tropical convection and stratospheric flow. We generally find weak connections, though some are statistically significant over the 100-year period and consistent with model results. Apparent multidecadal variations in the connection between the QBO and the investigated climate responses are consistent with a small effect in the presence of large variability, with one exception: the imprint on the northern polar vortex, which is seen in recent reanalysis data, is not found in the period 1908–1957. Conversely, an imprint in Berlin surface air temperature is only found in 1908–1957 but not in the recent period. Likewise, in the model simulations both links tend to appear alternatingly, suggesting a more systematic modulation due to a shift in the circulation for example. Over the Pacific warm pool, we find increased convection during easterly QBO, mainly in boreal winter in observation-based data as well as in the model simulations, with large variability. No QBO effects were found in the Indian monsoon strength or Atlantic hurricane frequency.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Climatology
08 Faculty of Science > Physics Institute > Climate and Environmental Physics
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Institute of Geography
08 Faculty of Science > Institute of Geography > Physical Geography

UniBE Contributor:

Brönnimann, Stefan; Malik, Abdul; Wegmann, Martin and Raible, Christoph

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology
900 History > 910 Geography & travel

ISSN:

1680-7316

Publisher:

European Geosciences Union

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

10 Jan 2017 09:14

Last Modified:

10 Jan 2017 09:14

Publisher DOI:

10.5194/acp-16-15529-2016

BORIS DOI:

10.7892/boris.91617

URI:

https://boris.unibe.ch/id/eprint/91617

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