Lidar observations of middle atmospheric gravity wave activity over Reunion island (20.8°S, 55.5°E): Climatological study
Résumé
In this paper, climatological characteristics of the gravity wave activities are studied using temperatureprofiles obtained from Rayleigh lidar located at Reunion Island (20.8°S, 55.5°E) over a period of ~14 years (1994-2007). Gravity wave (GW) study hasbeen performed over the height range from 30 to 65km. The present study documents the GW characteristics in terms of time (frequency), height (wave number) and GW associated Potential Energyand their seasonal dependences. The wave activity is clearly visible with the wave periods ranging from 260 min to 32 min. The dominant components have vertical wavelengths in the range of about ~4 km to 35 km. The potential energy over the height regionfrom 30 km to 65 km are calculated and presented. Itis found that the seasonal variation of potential energy is maximum during summer in the upperstratosphere and lower mesosphere. A semi-annual variation is seen in the gravity wave activity over allheight ranges in the months of February and August.