The 11-Year Solar Cycle Signature on Gravity Waves

Friday, 19 December 2014
Scott England and Chihoko Y. Cullens, University of California Berkeley, Berkeley, CA, United States
Upward-propagating atmospheric gravity waves are known to have a significant impact on the dynamics and energy budget of the middle and upper atmosphere. These waves are also known to be highly variable on almost all measured time-scales, thus their influence on the middle and upper atmosphere likely varies on the same time-scales. Several published works have reported the influence of the 11-year solar sunspot cycle on atmospheric gravity waves in the middle atmosphere, generally using 1 solar cycle of observations. These studies disagree on the magnitude and sign of the change in gravity wave amplitudes in response to the solar cycle. Here, the impacts of the 11-year solar cycle on gravity waves are investigated using two 50-year WACCM simulations. For these 50-year simulations, we output all gravity wave components, and it allows us to separate gravity wave responses by their sources and phase speeds. Our results show that the largest 11-year solar cycle signals on gravity wave drag exist at high-latitudes in winter from the stratosphere to the lower thermosphere.