The 11 year solar cycle signature on wave-driven dynamics in WACCM

Solar cycle signals are estimated by calculating the difference between solar maximum and minimum conditions. Simulations under both time-varying and fixed solar inputs show statistically significant responses in temperatures and winds in the Southern Hemisphere (SH) during austral winter and spring.

At solar maximum, the monthly mean, zonal mean temperature in the SH from July to October is cooler (~1-3 K) in the stratosphere and warmer (~1-4 K) in the mesosphere and the lower thermosphere (MLT). In solar maximum years, the SH polar vortex is more stable and its eastward speed is about 5-8 m s⁻¹ greater than during solar minimum. The increase in the eastward wind propagates downward and poleward from July to October in the SH.