The estimation of upper atmospheric wind profile updates from infrasound data

Understanding and specification of the higher altitudes of the atmosphere with global overage over all local times is hampered by the challenges to obtaining direct measurements in the upper atmosphere. The development of methods to measure the properties of the atmosphere above the stratopause is an active area of scientific research. Comprehensive observationally based specifications of the wind structure in the mesosphere and lower thermosphere are presently limited to empirical models that only capture the average climatology. In the past, various studies focused on the sensitivity of infrasound propagation to various upper atmospheric processes. It has been shown that the acoustic predictions using the empirical models are not always in agreement with observations, suggesting the use of infrasound as a remote sensing technique. In a previous study, we have reported on errors in the prediction of thermospheric celerities which were found to be in accord with the typical uncertainties in upper atmospheric wind and temperature specifications. In this presentation, we discuss the inverse problem of using infrasound data to estimate corrections to the upper atmospheric wind profiles given by the background climatology. We make use of a grid search method in combination with Bayesian statistics to analyze the uncertainties associated with the inverse solution and the nonlinearity of the inverse problem. The method is applied to the thermospheric arrival dataset that we have reported on previously.