Simulating the atmospheric response to the 11-year solar cycle forcing with the UM-UKCA model: the role of detection method and natural variability

Bednarz, Ewa Monika and Maycock, Amanda C. and Braesicke, Peter and Telford, Paul J. and Abraham, N. Luke and Pyle, John A. (2019) Simulating the atmospheric response to the 11-year solar cycle forcing with the UM-UKCA model: the role of detection method and natural variability. Atmospheric Chemistry and Physics, 19. 5209–5233. ISSN 1680-7316

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Abstract

The 11-year solar cycle forcing is recognised as a potentially important atmospheric forcing; however, there remain uncertainties in characterising the effects of the solar variability on the atmosphere from observations and models. Here we present the first detailed assessment of the atmospheric response to the 11-year solar cycle in the UM-UKCA chemistry-climate model using an ensemble of integrations over the recent past. Comparison of the model simulations is made with observations and reanalysis. Importantly, in contrast to the majority of previous studies of the solar cycle impacts, we pay particular attention to the role of detection method by comparing the results diagnosed using both a composite and a multiple linear regression method. We show that stratospheric solar responses diagnosed using both techniques largely agree with each other within the associated uncertainties; however, the results show that apparently different signals can be identified by the methods in the troposphere and in the tropical lower stratosphere. Lastly, we focus on the role of internal atmospheric variability on the detection of the 11-year solar responses by comparing the results diagnosed from individual model ensemble members (as opposed to those diagnosed from the full ensemble). We show overall agreement between the ensemble members in the tropical and mid-latitude mid-stratosphere-to-lower-mesosphere, but larger apparent differences at NH high latitudes during the dynamically active season. Our results highlight the need for long data sets for confident detection of solar cycle impacts in the atmosphere, as well as for more research on possible interdependence of the solar cycle forcing with other atmospheric forcings and processes (e.g. QBO, ENSO… etc.).

Item Type:
Journal Article
Journal or Publication Title:
Atmospheric Chemistry and Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1902
Subjects:
ID Code:
124249
Deposited By:
Deposited On:
26 Mar 2018 14:10
Refereed?:
Yes
Published?:
Published
Last Modified:
26 May 2020 06:35