The dunes act as obstacles, and obstacles cause winds to be deflected significantly to the right, in the southern hemisphere—in effect reorienting the southerly wind as a southwesterly wind.Naturally, I started thinking about "my right" with respect to what? Which way am I facing when I am determining which way is to the right. Since I usually look at a map where North is at the top, my right will always be west. If I was Australian and enjoyed seeing my country at the top, I would have South always at the top and my right would be east. If the southerly wind is being reorientated by the dunes, this distributes the sand in the southwest pattern which is seen in the photo. Southwesterly means that the winds are coming from the southwest, which means that they have been diverted to the west (my right, not the Australian's right, and as it turns out the not the right of the astronaut who took the picture since it looks like they inverted the photo to be oriented with its top to the north).
I recognize this way of speaking from my Meteorology books. These "rule of thumb" rules stating that if you are standing with your face to the wind, the low pressure will be to your right (or left, I do not remember). And what does "in the southern hemisphere" mean exactly? I am very visual, and I need to know where I am standing within a scenario to picture it and eventually understand it.