title: Infrasonic attenuation in the upper mesosphere-lower thermosphere: a comparison between Navier-Stokes and Burnett predictions.
abstract: This paper presents the results of a pilot study comparing the use of continuum and non-continuum fluid dynamics to predict infrasound attenuation in the rarefied lower thermosphere. The continuum approach is embodied by the Navier-Stokes equations, while the non-continuum method is implemented via the Burnett equations [Proc. London Math. Soc. 39, 385-430 (1935); 40, 382-435 (1936)]. In the Burnett framework, the coupling between stress tensor and heat flux affects the dispersion equation, leading to an attenuation coefficient smaller than its Navier-Stokes counterpart by amounts of order 0.1 dB/km at 0.1 Hz, 10 dB/km at 1 Hz, and 100 dB/km at 10 Hz. It has been observed that many measured thermospheric arrivals are stronger than current predictions based on continuum mechanics. In this context, the consistently smaller Burnett-based absorption is cautiously encouraging.
authors.affiliation: Department of Physics, University of Louisiana at Lafayette, P.O. Box 44210, Lafayette, Louisiana 70504.
authors.forename: Akinjide
authors.initials: A
authors.lastname: Akintunde
authors.affiliation: Department of Physics, University of Louisiana at Lafayette, P.O. Box 44210, Lafayette, Louisiana 70504.
authors.forename: Andi
authors.initials: A
authors.lastname: Petculescu