Near-surface structure of a large linear dune and an associated crossing dune of the northern Namib Sand Sea from Ground Penetrating Radar: Implications for the history of large linear dunes on Earth and Titan

•Ground Penetrating Radar images obtained of a large Namib Sand Sea linear dune.•Strata up to ∼ 10 m depth show scouring and abrupt changes.•Alternating strata reveal changes in dominant wind direction.•Subsurface patterns reveal down-axis transport of sand.•Implications for wind direction and sand transport on Saturn’s moon Titan.