The cities at the Gulf have been completely transformed in the recent decades on the oil wealth. Before the oil extraction began ~1970s all of them were small insignificant desert outposts. Since then the population of Gulf cities imploded 10 to 40 times, doubling every decade or so.
Vast sandy deserts nearly devoid of life, almost as desolate steppes, little rain and hard-to-survive summer day heat. This is what Tropical Dry climates feel like.