Characteristics of equatorial gravity waves derived from mesospheric airglow imaging observations

We present the characteristics of small-scale (< 100 km) gravity waves in the equatorial mesopause region derived from OH airglow imaging observations at Kototabang (100.3 degrees E, 0.2 degrees S), Indonesia, from 2002 to 2005. We adopted a method that could automatically detect gravity waves in the airglow images using two-dimensional cross power spectra of gravity waves. The propagation directions of the waves were likely controlled by zonal filtering due to stratospheric mean winds that show a quasi-biennial oscillation (QBO) and the presence of many wave sources in the troposphere.