关于这张图
The small crater in the middle of the image is at the upwind side of the dune field. There is a considerable amount of sand within the crater, with a relatively smooth surface and few dune forms. It is likely that this crater provides a source of available sand for the large dune field. Located in eastern Arabia is an unnamed crater, 120 kilometers (75 miles) across. The floor of this crater contains a large exposure of rocky material, a field of dark sand dunes, and numerous patches of what is probably fine-grain sand. The shape of the dunes indicate that prevailing winds have come from diff…
