Articles | Volume 15, issue 14
Research article
30 Jul 2015
Research article |  | 30 Jul 2015

Global distributions of overlapping gravity waves in HIRDLS data

C. J. Wright, S. M. Osprey, and J. C. Gille

Abstract. Data from the High Resolution Dynamics Limb Sounder (HIRDLS) instrument on NASA's Aura satellite are used to investigate the relative numerical variability of observed gravity wave packets as a function of both horizontal and vertical wavenumber, with support from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on TIMED. We see that these distributions are dominated by large vertical and small horizontal wavenumbers, and have a similar spectral form at all heights and latitudes, albeit with important differences. By dividing our observed wavenumber distribution into particular subspecies of waves, we demonstrate that these distributions exhibit significant temporal and spatial variability, and that small-scale variability associated with particular geophysical phenomena such as the monsoon arises due to variations in specific parts of the observed spectrum. We further show that the well-known Andes/Antarctic Peninsula gravity wave hotspot during southern winter, home to some of the largest wave fluxes on the planet, is made up of relatively few waves, but with a significantly increased flux per wave due to their spectral characteristics. These results have implications for the modelling of gravity wave phenomena.

Short summary
Data from the HIRDLS instrument are used to study the numerical variability of gravity waves. Observed distributions are dominated by long-vertical-short-horizontal-wavelength waves, with a similar spectral form at all locations. We further divide our data into subspecies by wavelength, and investigate variation in these subspecies in time and space. We show that the variations associated with particular phenomena arise due to changes in specific parts of the spectrum.
Final-revised paper