Statistical study of atmospheric gravity waves in the mesopause region observed by a lidar chain in eastern China

Abstract

Atmospheric gravity wave activities in the mesopause region have been observed and statistically investigated with a sodium lidar chain in eastern China. In total, there were 471 gravity waves identified from over 5400 h of observations at Hainan (19.99°N, 110.34°E), Hefei (31.87°N, 117.23°E), and Beijing (40.47°N, 115.97°E). These waves typically had vertical wavelengths of λz=2-4 km, observed periods of Tob=1-4 h, amplitude growth factors of β =-0.025 ~ + 0.05 km-1, and wave amplitudes of Aeβ * 90km=1.5-6%. Strong systematic parameter relationships were found, and they agree with the predictions of diffusive filtering theory. Statistical results show that the seasonal variability of gravity wave activity had a summer-maximum and winter-minimum characteristics in the mesopause region over eastern China. A qualitative interpretation is proposed regarding the seasonal and geographic variability observed by the lidar chain, based on analysis of source properties and influences from background wind, which vary by season.