The Shape of the Barchan Dunes in the Arkhangelsky

Sand dunes are beautiful sand patterns formed by the wind, and have been seen in many places on Mars. In particular barchan dunes, which have a crescent shape, propagate on solid ground under unidirectional winds and are very common on earth’s deserts and coasts, have been observed forming corridors on the floor of martian craters and also on the north pole. However, barchan dunes on Mars have different shapes and are larger than on Earth [1,2]. While barchans smaller than 10 m in width may be found on Earth, the smallest dark barchan dunes one can see in the MOC images of martian craters have a width of the order of one hundred meters. Which physical variables do compete for this remarkable difference?