I have this sentence as part of an abstract
Verification of space weather forecasts presents some unique challenges compared with other types of forecasts.
I go on to detail briefly what those challenges are. Now, these aspects aren't, in truth, entirely unique to this area, but are still much more of a factor than in other areas. I am trying to succinctly replace 'unique' with something more suitable.
I have toyed with 'peculiar' or 'idiosyncratic' but neither really appeals. 'Particular' might fit but I'm still not too happy with that.
Unique works because in the context because I think it also conveys a sense of these challenges being interesting, which doesn't come across so much with the other words mentioned.