When I copy it by using ctrl+C and then paste it into my editor, the journal name continues to be grl, whereas the desired behavior would be Geophys. Res. Lett.
Copy and paste of String constants is not yet supported. Either you add them manually to your bib file (eg. open in an editor) or you can add them using Library properties → Strings constants.
JabRef considers Strings as metadata, while copying and pasting only operates on entries.
However, it should be possible to search and parse String contants on pasting and adding them to the library. I suggest, you open an issue at our gihtub repo for this: