Ozone and temperature response of a chemistry climate model to the solar cycle and sea surface temperature

The results from a three-dimensional chemistry climate model (CCM) of the Center for Climate System Research/National Institute for Environmental Studies (CCSR/NIES) were analyzed for 1980-2000 to detect variations due to the 11 year solar cycle. Multiple regression analysis, including the constant, linear trend, solar, quasi-biennial oscillation, volcanic, and sea surface temperature (SST) terms, was applied for ozone and temperature of the CCM for the REF1 scenario of CCM Validation. Using observed SST as a lower boundary condition, the results suggest that the contribution of solar cycle forcing in the CCSR/NIES CCM is about 1% in ozone volume mixing ratio and 0.2 K in temperature per 100 units of 10.7 cm solar microwave flux in the tropical lower stratosphere for the period 1980-2000. A change in ozone transport may be the main factor for the solar signal of ozone concentration in the lower stratosphere. Another sensitivity experiment excluding solar cycle forcing shows a small solar response in the lower stratosphere, suggesting that the interannual variability of the SST could contribute to the solar term in the lower stratosphere through troposphere-stratosphere processes and/or have an effect as an artifact of interference due to the insufficient period for analysis.