Sand dunes often have a wavy surface what creates this kind of surface

The Bottom Line. Dunes and ripples are both bedforms: piles of stuff that is moved along the ground by the wind (or by some fluid, like water). They are formed in different ways, taking anywhere from minutes to millennia to respond to changes in wind patterns

From the topexospherethermospheremesospherestratosphere troposphere

The light is great source of energy