XP3A - Nook, Greenland on 10m WSPR

For some reason (Win 8.1?) I have had issues today uploading my WSPR spots (that is of others) to the database. I have restarted the software and reset the clock and now all seems to be OK.  Among the first uploads was a strong signal from XP3A in Nook, Greenland at 1932z.. Although strong (+4dB S/N) there was -4Hz Doppler on the signal, perhaps because the signal was coming through the Auroral Oval?

XP3A's QSL card

This was the first time I have seen/heard Greenland on 10m WSPR but I was lucky enough to work Greenland on 15m SSB handheld with my FT817 in my back garden some years ago on just a base loaded whip with  a counterpoise!   I think the mode then was double hop Es. It was an easy QSO. Being able to move the antenna for best signal helps.

Interestingly, a VE4 was suffering -4Hz Doppler just now (signal again passing through auroral oval?). I often see large Doppler shifts on signals crossing the Equator (e.g. on FR1GZ) and I assumes this is due to moving F layers (spread F) as signals cross the magnetic Equator. I would expect TEP signals to have considerable Doppler too.