Estimation of gravity-wave momentum flux in the Antarctic stratosphere using observations from long-duration balloons

In September and October 2005, 27 superpressure balloons were released from McMurdo, Antarctica and drifted in the polar lower stratosphere for 2 months on average. Continuous observations of wind, pressure and temperature were performed during the flights. A technique using wavelet analysis is developed to detect gravity wave packets in the balloon observations and to estimate the momentum flux carried by gravity waves in the Antarctic stratosphere. This enables us to provide a geographical distribution of the gravity-wave momentum flux south of 50°S and identify strong topographical sources such as the Antarctic Peninsula. Significant other sources over the oceans are investigated as well. The gravity wave activity as a function of the location of the observations with respect to the vortex edge is also studied.