Investigating seasonal gravity wave activity in the summer polar mesosphere. (May 2015)

• Record Type: Journal Article
• Authors: Zhao, Y.; Taylor, M.J.; Randall, C.E.; Lumpe, J.D.; Siskind, D.E.; Bailey, S.M.; Russell, J.M.
• Is Part Of: Journal of atmospheric and solar-terrestrial physics. Volume 127(2015:May)
• Page Start: 8
• Page End: 20
• Publication Date: 2015-05
• Subjects: Geophysics -- Periodicals; Atmospheric physics -- Periodicals; Géophysique -- Périodiques; Météorologie physique -- Périodiques; Electronic journals; 551.51
• DOI: 10.1016/j.jastp.2015.03.008
• Languages: English
• ISSNs: 1364-6826

Abstract

Abstract: The NASA Aeronomy of Ice in the Mesosphere (AIM) satellite is the first spaceborne mission dedicated to studying high-altitude (~83 km) Polar Mesospheric Clouds (PMCs). Since its launch in 2007, the Cloud Imaging and Particle Size (CIPS) instrument onboard AIM has obtained large-field, high resolution (25 km 2 /pixel) images of the PMCs, enabling a unique investigation of mesospheric gravity wave activity in the summer polar mesosphere where previous measurements have been sparse. In this study, we have analyzed 12 consecutive seasons of AIM/CIPS PMC albedo data to determine the statistical properties of medium and large horizontal scale (>100 km) gravity waves present in the PMC data. Over 60, 000 wave events with horizontal scale-sizes ranging up to >2000 km have been identified and measured, revealing a wealth of wave events particularly in the ~300–800 km range where our analysis sensitivity is largest. These data are ideal for investigating the intra-seasonal, inter-annual and hemispheric variability of these waves as observed over the whole summer polar cap regions. Throughout this 6 year study, the wave activity in the southern hemisphere was found to be consistently 10–15% higher than in the northern hemisphere and both the northern and southern hemisphere wave activity was determined to decrease systematically (by ~15%) during the course of each summer season. This decrease agrees well with previous seasonal stratospheric studies of variations in the wave energy, suggesting a direct influence of the lower atmospheric sources on polar mesospheric dynamics. Very similar and consistent results were also found from season to season in both hemispheres providing new information for gravity wave modeling and dynamical studies of the high-latitude summer-time mesosphere. Highlights: Gravity waves (>100 km) identified in 12 seasons of AIM/CIPS PMC albedo data. Abundance of waves in the 300–800 km range in both summer polar hemispheres. Wave activity decreases systematically by ~15% in the both polar hemispheres. Gravity waves are 10–15% more frequent in the southern than northern hemisphere. New evidence of influences of lower atmospheric sources on mesospheric dynamics.