We report a detailed analysis of characteristics of stability based on high-resolution temperature and horizontal wind measurement made with a Na lidar at the Andes Lidar Observatory, located in Cerro Pachón, Chile (30.2º S, 70.7º W). The general probability of convective and dynamical instability are 5.3% and 16.4%. Contributions from different scales of GWs have been calculated. Large wind shear and dynamical instabilities are mainly generated because all GWs with different frequencies exist simultaneously. Isolated parts of GWs have much less contribution to the generation of instabilities. The dynamical instability is mainly contributed from less stable stratification and large wind shear together. Either factor can lead to about 15% of dynamical instability. Biases of the instability probabilities due to photon noise have been analyzed, and the biases have been subtracted from the measured probabilities.