Invariant Sets and Explicit Solutions to a Third-Order Model for the Shearless Stratified Turbulent Flow

We study dynamics of the shearless stratified turbulent flows. Using the method of differential constraints we find a class of explicit solutions to the problem under consideration and establish that the differential constraint obtained coincides with the well-known Zeman--Lumley model for stratified flows.Comment: arxiv version is already officia

CLUSIM: A Synthetic Aperture Radar Clutter Simulator for Planetary Exploration

In this paper we present the CLUtter SIMulator (CLUSIM), a special program simulating radar side echoes from rough planetary surfaces using realistic topography data sets. A numerical model of realistic topography of the Martian surface, based on Mars Orbiter Laser Altimeter data, is developed. A specially developed computer routine for evaluation of wideband radar echoes reflected from rough surfaces, capable of aperture synthesis simulation, is described. A synthetic radargram for a portion of Mars Express (MEX) orbit 9466 is computed and validated against experimental data obtained by the MARSIS radar instrument. Finally, a previously developed ionospheric phase correction procedure is numerically tested with new simulated echo signals. Impact of the surface clutter on the ionospheric correction procedure is investigated with a direct numerical comparison to a known benchmark result, which shows robustness of the correction algorithm with respect to the surface clutter