Equatorial Atmosphere Radar observations of short vertical wavelength gravity waves in the upper troposphere and lower stratosphere region induced by localized convection

Abstract

Equatorial Atmosphere Radar (EAR) observations made at Koto Tabang (0.2°S, 100.32°E) revealed that gravity waves with a short vertical wavelength (∼2-4 km) were evident in the upper troposphere and lower stratosphere (UTLS). Results are based on two convective events observed on 11 April and 26 April 2004. Above the convective region (∼12-13 km heights) the decrease in the vertical wavelength (λz) found in vertical wind profiles was noticeable. Large portions of the induced gravity waves with short λz dissipated in the lower stratosphere and hence their role is considered to be of importance for the dynamics of UTLS region. Gradual decrease in λz of gravity waves between 12 km and 20 km heights is partly made by a steady increase in Brunt Väisälla frequency from ∼12 km to 20 km heights. The decrease in amplitude in UTLS may be due to damping mechanism. Copyright 2006 by the American Geophysical Union.