Summary: Intermediate-scale tropical inertia gravity waves observed during the
and M. J. Alexander2
Received 17 August 2007; revised 25 January 2008; accepted 22 February 2008; published 16 July 2008.
 We describe a 2-day wave event observed in high-resolution radiosonde soundings of
horizontal wind and temperature taken during the TWP-ICE experiment in Darwin area.
The vertical profiles of temperature, zonal and meridional wind speeds are analyzed
using the S-transform wavelet analysis. Results of the analysis reveal the presence of
2-day inertia gravity waves in the stratosphere between 20 and 27 km. The wave presents
vertical and horizontal wavelengths of around 6 km and 7220 km respectively. The wave
was observed to propagate southeastward during the end of the easterly phase of the
QBO. The total vertical momentum flux associated with the waves is estimated to be 1 to
2.2 Â 10À3
. This is of the same order of magnitude as previous observations of 4
10 day Kelvin waves in the lower stratosphere.
Citation: Evan, S., and M. J. Alexander (2008), Intermediate-scale tropical inertia gravity waves observed during the TWP-ICE
campaign, J. Geophys. Res., 113, D14104, doi:10.1029/2007JD009289.