Actually,
Ariel at its roots is more masculine, but has moved into the fem realm as well and more strongly so since "The Little Mermaid". The problem w/ N. Am. is people are so influenced by Disney movies that the movie image overshadows the reality of a name one way or another. That's why if I used the name for a girl, I'd spell it
Arielle in order to make it clear it was fem. My Jewish friends may appreciate the distinction.