Is this surface available? Asphalt
I thought you could only pick those that exist on the tour.
You're right that you can only pick surfaces on the tour, but I think
that it qualifies as a type of Hard court, and that the ITF doesn't differentiate between subtypes. At least, I don't know of any tournaments on tour that use Asphalt, but it's clearly allowed. It is a bit of a minor mystery to me as well
Also, it looks like, at least from the DC website, that this is the first ever Zone I or higher tie on the surface, which is an interesting choice.