In San Francisco, the area South of Market Street is called SoMa. The part of town North of the Panhandle is known as NoPa. Around the intersection of North Oakland, Berkeley and Emeryville, real estate brokers are pitching properties as part of NOBE. An area of downtown Oakland is being branded as KoNo, short for Koreatown Northgate. But no one actually calls it that, or at least, not yet.
There is not really a name for this naming convention. They are not quite acronyms, not quite portmanteaus, and not just abbreviations. We at 99% Invisible have been calling them acronames.