Heat and Constituent Flux due to Dissipating Gravity Waves and Turbulence over the Andes Lidar Observatory

Abstract:

The vertical transport by gravity waves and turbulent mixing plays a fundamental role in establishing the thermal and constituent structures of the Mesosphere and Lower Thermosphere (MLT) region. By using the high resolution Na Doppler Lidar measurements, located at Andes Lidar Observatory, Cerro Pechón, Chile (30.0⁰S, 71.0⁰W), direct measurements of vertical fluxes of heat and constituent induced by dissipating but non-breaking gravity waves are derived from vertical wind, temperature and sodium density profiles between 85 and 100 km. Furthermore, estimate of eddy heat and constituent fluxes of the turbulent mixing generated by breaking gravity waves can also be made by using the upgraded ultra-high resolution Na Doppler Lidar. Additionally, the associated eddy diffusion coefficients (k_H and k_zz) are calculated for the first time. The results show that the vertical transport velocities of mesospheric Na and heat caused by turbulent mixing are comparable with dynamical and chemical transport velocities by dissipating GWs. These observations will certainly benefit the parameterization of GW models and help us understand of the vertical transport better in the MLT region.