Summary: Observation and analysis of a large amplitude
mountain wave event over the Antarctic peninsula
M. Joan Alexander1
and Hector Teitelbaum2
Received 20 December 2006; revised 27 April 2007; accepted 31 July 2007; published 7 November 2007.
 We use measurements from the Atmospheric Infrared Sounder (AIRS) on the AQUA
satellite to observe the 3-dimensional structure of a gravity wave event over the
Antarctic peninsula, and determine the horizontal and vertical wavelengths, propagation
direction, and temperature amplitude, and from these we estimate wave momentum
flux. Using theoretical knowledge of the weighting functions and radiative transfer for
AIRS radiance measurements at temperature sensitive channels in the infrared, we derive a
method of estimating wave temperature amplitude directly from the radiance
measurements. Comparison of the radiance-based temperature amplitudes to the
temperature amplitude in AIRS retrieved temperature fields shows close agreement.
Because the radiances have 3-times better horizontal resolution than the retrievals, our
analysis suggests we can routinely observe important geophysical properties of waves
with horizontal wavelengths as short as 80 km using AIRS radiances. We further analyze a
nearly identical wave event appearing in the European Centre for Medium Range
Forecasts (ECMWF) temperature and wind fields from both assimilation and forecast data.
Analysis of the ECMWF data and nearby radiosonde wind profiles allows the