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The 11 year solar cycle signal in transient simulations from the Whole Atmosphere Community Climate Model

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Chiodo, G. and Calvo Fernández, Natalia and Marsh, D. R. and García Herrera, Ricardo (2012) The 11 year solar cycle signal in transient simulations from the Whole Atmosphere Community Climate Model. Journal of geophysical research-atmospheres, 117 . ISSN 0148-0227

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Official URL: http://dx.doi.org/10.1029/2011JD016393




Abstract

The atmospheric response to the 11 year solar cycle (SC) and its combination with the quasi-biennal oscillation (QBO) are analyzed in four simulations of the Whole Atmosphere Community Climate Model version 3.5 (WACCM3.5), which were performed with observed sea surface temperatures, volcanic eruptions, greenhouse gases, and a nudged QBO. The analysis focuses on the annual mean response of the model to the SC and on the evolution of the solar signal during the Northern Hemispheric winter. WACCM3.5 simulates a significantly warmer stratosphere under solar maximum conditions compared to solar minimum. The vertical structure of the signal in temperature and ozone at low latitudes agrees with observations better than previous versions of the model. The temperature and wind response in the extratropics is more uncertain because of its seasonal dependence and the large dynamical variability of the polar vortex. However, all four simulations reproduce the observed downward propagation of zonal wind anomalies from the upper stratosphere to the lower stratosphere during boreal winter resulting from solar-induced modulation of the polar night jet and the Brewer-Dobson circulation. Combined QBO-SC effects in the extratropics are consistent with observations, but they are not robust across the ensemble members. During boreal winter, solar signals are also found in tropospheric circulation and surface temperature. Overall, these results confirm the plausibility of proposed dynamical mechanisms driving the atmospheric response to the SC. The improvement of the model climatology and variability in the polar stratosphere is the basis for the success in simulating the evolution and magnitude of the solar signal.


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© 2012 by the American Geophysical Union. The authors thank Katja Matthes for instructive comments and fruitful discussions. G. Chiodo was supported by the Spanish Project CONSOLIDER (grant CSD2007-00050-II-PR4/07), TRODIM (grant CGL2007-65891-CO5-02), and the Spanish Ministry of Education in the framework of the "FPU" doctoral fellowship (grant AP2009-0064). N. Calvo was partially supported by the Advanced Study Program (ASP) at NCAR.

Uncontrolled Keywords:Quasi-biennial oscillation; North polar-region; Stratospheric ozone; Dynamical response; Middle atmosphere; Uv-radiation; Night jet; Variability Qbo; Temperature
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
Sciences > Physics > Atmospheric physics
ID Code:25473
Deposited On:23 May 2014 07:55
Last Modified:10 Dec 2018 15:05

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