Articles | Volume 33, issue 12
Ann. Geophys., 33, 1479–1484, 2015
Ann. Geophys., 33, 1479–1484, 2015

Regular paper 01 Dec 2015

Regular paper | 01 Dec 2015

Gravity wave transmission diagram

Y. Tomikawa1,2 Y. Tomikawa
  • 1National Institute of Polar Research, Tokyo, Japan
  • 2SOKENDAI (The Graduate University for Advanced Studies), Tokyo, Japan

Abstract. A new method of obtaining power spectral distribution of gravity waves as a function of ground-based horizontal phase speed and propagation direction from airglow observations has recently been proposed. To explain gravity wave power spectrum anisotropy, a new gravity wave transmission diagram was developed in this study. Gravity wave transmissivity depends on the existence of critical and turning levels for waves that are determined by background horizontal wind distributions. Gravity wave transmission diagrams for different horizontal wavelengths in simple background horizontal winds with constant vertical shear indicate that the effects of the turning level reflection are significant and strongly dependent on the horizontal wavelength.

Short summary
A possibility of gravity wave propagation from a source region to the airglow layer around the mesopause has been discussed based on the gravity wave blocking diagram taking into account the critical level filtering alone. This paper proposes a new gravity wave transmission diagram in which both the critical level filtering and turning level reflection of gravity waves are considered. It shows a significantly different distribution of gravity wave transmissivity from the blocking diagram.