[_delirium]

Interesting, in Denmark, å/aa are generally interchangeable in placenames. Some people have strong preferences, but the preferences aren't uniform. Aarhus/Århus for example can be spelled either way; even the municipal government has switched back and forth about which one it recommends (it switched to Århus in 1948, and back to Aarhus in 2011).

With personal names, I've usually gone by what the person themselves does when they write in English. It's quite common for people to use a different spelling in their "English" professional life. Sometimes this is å->aa, other times it is even just å->a. In this case, Knausgård appears to spell his own name as Knausgaard when writing in English, so it doesn't seem disrespectful to me if people writing about him in English spell his name the same way he has it printed on the cover of his own English-edition books.