Topography influences megadune distribution and morphology.

Area of Science:

• Geomorphology
• Planetary Science
• Aeolian Processes

Background:

• Dune formation and maximum size are not fully understood.
• Previous theories focused on atmospheric and sediment constraints.

Purpose of the Study:

• Investigate the role of topography in megadune formation.
• Identify controls on maximum dune size.

Main Methods:

• Global mapping of Earth's megadunes.
• Dune simulation modeling under varied topographic conditions.

Main Results:

• Megadunes are found near mountains and in depressions.
• Topography creates shear stress gradients, accelerating sand accumulation and dune growth.
• Surrounding topography modifies wind regimes, increasing dune aspect ratios.

Conclusions:

• Terrain-induced wind heterogeneity is key to megadune formation.
• This mechanism applies to both Earth and extraterrestrial bodies.
• Topography fundamentally controls massive aeolian landform evolution.