Global and Seasonal Variations of the Intermittency of Gravity Waves in Airglow Imager Observation and Whole Atmosphere Community Climate Model (WACCM)

Friday, 19 December 2014
Bing Cao and Alan Z Liu, Embry-Riddle Aeronautical University, Daytona Beach, FL, United States
Gravity waves can dramatically impact the dynamics and energy budget of the middle and upper atmosphere due to the fact that they can transfer momentum and energy. Since the waves with specific properties will not generally be occurring throughout the entire area and time, factors that can describe the spatial and/or temporal intermittency of gravity waves should be considered in the Global Circulation Model (GCM). In this work, observation data from all-sky airglow imager is used to analyze the intermittent nature of gravity waves in mesopause region. The probability density functions (pdfs) of momentum flux show two distinct regions of distribution. Main body of pdfs follows a log-normal distribution; at the tail for larger magnitudes, they deviate from the log-normal distribution and follow a power-law distribution. Also, multi-year simulation results from Whole Atmosphere Community Climate Model (WACCM) are used. The gravity waves drag (GWD) data is generated hourly in global range. By analyzing the pdfs of the GWD magnitudes, the global and seasonal pattern of intermittency of the gravity waves is discussed and compared with the results from the observation data.