Propagation directions of the mesospheric monochromatic inertial gravity waves observed with a lidar at SOR, NM

The University of Illinois Na wind/temperature lidar data collected at the Starfire Optical Range (SOR: 35N, 106.5W), NM, can be used to extract the dominant monochromatic inertial gravity waves and to characterize their features. By using simultaneously measured horizontal wind and temperature profiles the vertical wavelengths, intrinsic periods, and propagation directions can be determined using the hodograph method. A total of 700 waves were analyzed from about 300 h of observations. Waves with vertical wavelengths between 2 and 20 km and intrinsic periods between 1 and 20 h were fully characterized. 84.4% of the waves were propagating upwards. There was a prevailing direction towards the northeast in upward waves' horizontal propagations over the year. This prevailing direction existed also in spring, summer and autumn. In winter, most waves propagated to the south and west. The filter theory of gravity waves propagating through the middle atmosphere can be used to give an explanation on the observations. Propagation directions of downward waves showed no prevailing directions over the year. A discussion was given on their different features for different seasons.