Momentum flux estimates accompanying multi-scale gravity waves over Mt. Cook, New Zealand on 13 July 2014 during the DEEPWAVE campaign

Katrina Bossert, University of Colorado Boulder
David C. Fritts, GATS, Inc.
Pierre-Dominique Pautet, Utah State University
Bifford P. Williams, GATS, Inc.
Michael J. Taylor, Utah State University
Bernd Kaifler, Institute of Atmospheric Physics, German Aerospace Center
Andrea Dornbrack, Institute of Atmospheric Physics, German Aerospace Center
Iain M. Reid, University of Adelaide
Damian J. Murphy, Australian Antarctic Division, Department of the Environment
Andrew J. Spargo, ATRAD Pty Ltd.
Andrew D. MacKinnon, ATRAD Pty Ltd.


Observations performed with a Rayleigh lidar and an Advanced Mesosphere Temperature Mapper aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V research aircraft on 13 July 2014 during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) measurement program revealed a large-amplitude, multiscale gravity wave (GW) environment extending from ~20 to 90 km on flight tracks over Mount Cook, New Zealand. Data from four successive flight tracks are employed here to assess the characteristics and variability of the larger- and smaller-scale GWs, including their spatial scales, amplitudes, phase speeds, and momentum fluxes. On each flight, a large-scale mountain wave (MW) having a horizontal wavelength ~200–300 km was observed. Smaller-scale GWs over the island appeared to correlate within the warmer phase of this large-scale MW. This analysis reveals that momentum fluxes accompanying small-scale MWs and propagating GWs significantly exceed those of the large-scale MW and the mean values typical for these altitudes, with maxima for the various small-scale events in the range ~20–105 m2 s−2.