Complex MHD-AGW nature of wave packets generated by solar terminator

The mesosphere lower thermosphere photometer (MLTP) which operates at OH, O2 , O(1 D) and O(1 S) emission intensity in relative units and Rayleigh lidar was operated simultaneously to investigate the wave propagation characteristics from Gadanki, India (13.5o N, 79.2o E) during October 2009. The two days of quality data was collected on October 22-23, 2009 and October 23-24, 2009. The mesospheric temperatures were derived using ratio method for OH airglow data for simultaneous study. The lidar data was averaged for 30 minutes in time and 75-80 km range for a comparison with airglow deduced temperatures. It was found that OH temperatures are in good agreement with lidar derived height averaged temperature values throughout the time of operation on both the days. It is also observed that on October 23-24, the OH temperatures as well as lidar temperature data show significantly larger wave amplitudes than October 22-23, 2009. The Fourier analysis on mesospheric OH temperature data revealed the presence of a strong wave with periodicity of 0.6 and 1 hr. It is noticed that these waves were present in lidar data also throughout the altitude range of 40 -75 km on both the days indicating secular wave propagation on this occasion. These are first such results on wave propagation using simultaneous airglow and Rayleigh lidar temperature measurements over Indian zone. We elaborate the system details of MLTP and validate the MLTP observed temperature values with Rayleigh lidar measurements and also discuss about the wave propagation characteristics on both the days.