A method for determination of internal gravity wave parameters from a vertical temperature or density profile measurement in the Earth’s atmosphere

A method for determination of internal gravity wave (IGW) parameters from a single vertical temperature or density profile measurement in the Earth’s atmosphere has been developed. This method may be used for the analysis of profiles measured by any techniques in which the accuracy is enough to measure small (∼1%) amplitudes of the temperature or density fluctuations in the atmosphere. The criterion for the IGW identification has been formulated and argued. In the case when this criterion is satisfied then analyzed fluctuations can be considered as wave-induced. The method is based upon the analysis of relative amplitude thresholds of the temperature or density wave field and upon linear IGW saturation theory in which amplitude thresholds are restricted by dynamical instability processes in the atmosphere. In order to approbate the method we have used data of simultaneous radiosonde measurements of the temperature and wind velocity in the Earth’s stratosphere where the saturated IGW propagation has been detected. It is shown that the application of the method to radio occultation temperature data gives the possibility to identify IGWs in the Earth’s lower stratosphere and to determine values of key wave parameters.