Stratospheric and tropospheric response to enhanced solar UV radiation: A model study

Abstract

The atmospheric response to the 11-year solar cycle is studied using a fully interactive 3-D coupled chemistry-general circulation model with a complete seasonal cycle. The stratosphere-troposphere system shows partly significant response to a realistic solar cycle enhancement of UV radiation. This response consists of increases in stratospheric ozone and temperature, giving rise to changes in the zonal wind from the stratosphere into the troposphere. Computed changes of stratospheric ozone, temperature, zonal wind and geopotential heights are generally in agreement with observed changes between solar minimum and solar maximum. Observed pattern changes of the stratospheric response between early and late winter are approximately reproduced by the model. Our radiative forcing results show that the 11-year solar cycle effect on global mean temperature is negligible, but simulated responses of sea level pressure do suggest that regional effects are probably significant, e.g. by affecting the North Atlantic Oscillation.