Eects of Atmospheric Multipath Propagation on Radio Occultation Observables

Multipath propagation is a common source of error in radio occultation experiments in dense atmospheres. If not correctly detected and mapped into the ray asymptote structure, multipath eects produce unrecoverable errors in the inverse problem for the refractive index prole. Raytracing can be used to clearly illustrate multi-path caused by interacting signals following closely spaced paths in the atmosphere. Such dynamic signals occur in connection with sharp variations in refractivity with height and result in multivalued frequency with time. Closed-loop radio receivers based on phase-locked loops that are designed to receive single-valued frequency signals will fail to track these dynamic multivalued signals. SUMMARY The increasing use of radio occultation to determine atmospheric structure and climate motivates a continuing examination of data collection, processing, and interpretation methods in the presence of atmospheric multi-path propagation. Multipath propagation is a common source of error in radio occultation experiments in dense atmospheres. If not correctly detected and mapped into the ray asymptote structure, multipath eects produce unrecoverable errors in the inverse problem for the refractive index prole. In order to use backprojection methods to mitigate multipath eects in the refractive index prole, it is im