Gravity waves GW) are the result of the imbalance between the gravity and pressure gradient forces which act as restoring forces in the atmosphere. These waves are responsible for energy and momentum flux transport from the lower to upper atmosphere. Various studies have shown that the summer mesosphere is colder than the winter one at middle latitudes, which is incompatible with simple radiative equilibrium. This phenomenon is explained in terms of GW breaking and dissipation, with energy and momentum being deposited in the region. In the present work we will use atmospheric data, between 80 and 100 km altitude, measured by all-sky CCD imagers, lidar and meteor radar over Cachoeira Paulista (22.7 ° S, 45 ° W) and Sao Jose dos Campos (23.1 ° S, 45.9 °W). These data will enable a comprehensive study of the momentum flux and variance due to GW over this region. Furthermore, the use of reliable techniques is necessary for a good reliability in results. It is known that prevailing winds in the MLT region, mainly atmospheric tides, may influence the measurements of variance and momentum flux due to GW. Hocking's (2005) technique, that was used during the thesis work of this scholarship candidate, have shown the tidal influence on the measured variances, this deficiency was discovered and corrected by the candidate in her thesis, making the measurements more reliable. Thus, we intend to use this technique as a parameter in the comparison of the results and the validation of the other techniques to be used. The implementation of this project will enable that the momentum flux and energy due to GW to be inferred more reliably. In conclusion, this study will contribute significantly to research in GW, as well as the general dynamics of the mesosphere and lower thermosphere.
News published in Agência FAPESP Newsletter about the scholarship: