For instance...
"SkyrimClearMA_A".
Obviously, "Skyrim" stands for the worldspace/province. "Clear" specifies what type. "_A" specifies that it will sport an aurora at night.
...But what's the "MA"? There are others, CO, FF, RE, SN, TU, VT, and then some without any specified odd two-letter code. What do they stand for?

Maybe Ocean, if you were on a boat... Oh that would be awesome!