I need to model the white hemisphere on top of the telescope tower of this observatory. As you can see, the hemisphere is not smooth, but it has some regular reliefs (I think they are called creases, but I am not sure). I have tried to use insets, blevels and creases, but I cannot get the desired results. Moreover, I didn't find anything in Google, but I am not sure how these reliefs are called, so probably I didn't search properly.
How would you proceed to create the reliefs of this hemisphere? (I have already made the hemisphere, it is just these regular edges in relief that I don't know how to model).