Decadal Continuous Meteor-Radar Estimation of the Mesopause Gravity Wave Momentum Fluxes over Mohe: Capability Evaluation and Interannual Variation

Abstract

In the present work, the momentum fluxes of gravity wave (GW) around the mesopause are estimated, using the decadal continuous observations by meteor radar at Mohe (53.5°N, 122.3°E). Applying the Hocking’s (2005) approach with the modified-composite-day (MCD) analysis, the GW momentum fluxes of short-periods (less than 2 h) are estimated month by month. As the first step, several experiments are designed to evaluate the accuracy and uncertainty in the estimation. The results show that Mohe meteor radar has the ability to give reasonable estimations on the GW momentum fluxes at a height of 82–94 km, in which errors are generally less than 5 m2/s2. The uncertainty induced by different angular information of the detected meteor in each month achieves ~2 m2/s2. It is inferred that the variability of the GW momentum fluxes over 2 m2/s2 can be distinguished in the observation. The interannual variation of the estimated GW momentum fluxes show a significant enhancement in 2012, and a depression in 2013, with a fluctuation over ±10 m2/s2 at 82 km. However, no obvious quasi-biennial oscillation (QBO) -like signal has been found in the Lomb–Scargle periodogram.

Keywords

• gravity wave
• momentum fluxes
• meteor radar