A Case Study of Mesospheric Wave Periods and Horizontal Structures over a Low Latitude Station, Allahabad (India)

We report the measurements of short period gravity waves with the help of all sky imager operated at OH nightglow wavelenghts during 21-22 and 23-24 April 2009 from Allahabad (25.5° N, 81.9° E), India. We note persistent oscillations on both the nights with wave periods ranging from 0.4 to 1.5 hours. To quantify the zonal and meridional scales of these waves, we analyze the intensity variability noted in zenith angles 30°, 15° and 0° in East, West, North and South directions. We find the wavelengths of observed waves to vary from 40 to 100 km. We discuss these observed wave properties in connection to their importance in global circulation of upper atmosphere.