The effect of inhomogeneous winds on internal gravity wave propagation in a dissipative atmosphere

Ray tracing method is used to calculate the propagation of gravity waves with various period and wavelength from ground to the observation height of 220km in a dissipative atmosphere. The results show that the refraction caused by wind and wind shear vertical to the propagation direction leads to considerable changes of wave propagating direction. Under the condition of propagating! along strong wind,large number of waves cannot reach the observation height,due mainly to critical, coupling. While under the condition of propagating along weak wind, waves with short period can! reach observation height, due to dopler shift of wave frequency. Under the condition of propagating: against strong wind,waves with period less than 18min cannot reach observation height,for they are reflected below thermosphere. And under the condition of propagating against weak wind, most of medium-scale gravity waves can reach observation height., The Travelling Ionosphere Disturbances (TIDs) observed by Wuhan Ionosphere Observatory is statistically analyzed. The distribution of TIDs with thermosphere wind is in agreement with the numerical results.