Our man Olaf describes his father's reasoning for the opposing winds

"After our giant brothers had launched our little craft for us, they
were most cordially regretful at parting, and evinced much solicitude
for our safety. My father swore by the Gods Odin and Thor that he
would surely return again within a year or two and pay them another
visit. And thus we bade them adieu. We made ready and hoisted our
sail, but there was little breeze. We were becalmed within an hour
after our giant friends had left us and started on their return trip.
The winds were constantly blowing south, that is, they were blowing
from northern opening of the earth toward that which we knew to be
south, but which, according to our compass's pointing finger, was
directly north. For three days we tried to sail, and to beat against
the wind, but to no avail. Whereupon my father said: "My son, to
return by the same route as we came in is impossible at this time of
year. I wonder why we did not think of this before. We have been here
almost two and a half years; therefore, this is the season when the
sun is beginning to shine in at the southern opening of the earth.
The long cold night is on in the Spitzbergen country." "What shell we
do?" I inquired. "There is only one thing we can do," my father
replied, "and that is to go south." Accordingly, he turned the craft
about, gave it full reef, and started by the compass north but, in
fact, directly south. The wind was strong, and we seemed to have
struck a current that was running with remarkable swiftness in the
same direction."

Jens Jansen informs us that during the northern winter on the
outside, the atmosphere gets sucked into the interior, and blows
out through Antarctica.

Dean