Stability Characteristics of the Mesopause Region Above the Andes

We report a detailed analysis of atmospheric stabilities in the mesopause region (85–100 km) based on over 2,000 hr high-resolution temperature and horizontal wind measurements made with Na lidar at Andes Lidar Observatory, located Cerro Pachón, Chile (30.25°S, 70.74°W). The square Brunt–Väisälä frequency Richardson number are calculated, occurrence probabilities convective dynamic instabilities derived. An approach to assess biases due measurement uncertainties is used obtain more accurate probabilities. overall 2.7% 6.7%, respectively. High-, medium-, low- gravity wave (GW) contributions these isolated, which show that high-frequency GWs contribute most but simultaneous presence high- medium much effective increasing Convective mainly generated because joint effect different-scale GWs. Isolated parts have less contribution generation both instabilities. instability contributed from stable stratification large shear together. Either factor can lead about 15% instability.