Local time variation of gravity wave momentum fluxes and their relationship with the tides derived from LIDAR measurements

• Diurnal components of wind, momentum flux and forcing from LIDAR at SOR.
• GW forcing on the tidal amplitude has an altitude and directional dependence.
• The GW momentum flux shows clear modulation by the tide.
• Results agree well with past modeling but is different from some previous observations.

Gravity waves and atmospheric tides have strong interactions in the mesopause region and are major contributors to the large variabilities in this region. How these two large perturbations interact with each other is not well understood. Wind and temperature measurements from a Na LIDAR at the Starfire Optical Range (35.0°N, 106.5°W), New Mexico from 24 nights between 1998 and 2000 are used to derive local time variations of gravity wave momentum flux and corresponding local time tidal variation of the background wind. The diurnal component of the momentum flux shows a clear modulation by the tide. The gravity wave forcing on the diurnal tidal amplitudes is shown to have an altitudinal and directional dependence.