A Technique for the Analysis of Radio Occultation Data to Retrieve Atmospheric Properties and Associated Uncertainties

Among the techniques for atmospheric sounding, radio occultation enables an in depth investigation of vertical profiles from the ionosphere to the troposphere by measuring the radio frequency signal associated to the propagation medium. A precise characterization of the atmospheric layers requires a thorough processing of the raw radio tracking data to estimate the thermodynamic properties of the atmosphere and their related uncertainties. In this work, we present a method to retrieve refractivity, density, pressure, and temperature profiles with the associated uncertainties by analyzing a set of raw radio tracking data occulted by the atmosphere. This technique is also well suited to process two-way Doppler measurements that are not acquired during dedicated occultation campaigns. The NASA mission Mars Reconnaissance Orbiter (MRO) provided a significant amount of radio occultation data that were not planned for atmospheric sounding, but were caused by the spacecraft orbit geometry. Our analysis of one of these occultation profiles with the proposed method allows indicating that MRO occultation datasets provide crucial information regarding Mars' troposphere that can be used as input of general circulation models.