Jökull - 01.12.1969, Page 78

3. 9. 15. 21. 27. 3. 9. 15. 21. 27 3. 9. 15. 21. 27 3. 9. 15. 21. 27.
20
0
-20
Fig. 6. Geostrophic wind component out from the ice edge in the winter 1964 to 1965. Broken
lines in region M, dotted lines region S. — Note the strong outwards wincl in Dec. ancl Feb.

"v s V" t • .\ *. \ N V \ t' 1 \ ✓ ✓ ''•’v.N •' \ N / \ > «. *• /*"" \ / \ \ . • y •. N >
• N .* \y v r i- / \ * \ /* • \/ •/ • / / / \ \ t • \/ .'
DE S. Jí N. FEB R. MAR Z
On the 13th of February open pack ice was
reported at the northwest coast where it re-
mained the following weeks. At the same time
the pack ice approached land farther east, and
on the 24th of February the first floes liit the
coast. The following day a tongue of ice had
passecl to the south of Langanes and continu-
ed on its southwards course the following days.
See Fig. 8.
Great changes have taken place since the
beginning of the month. In region S the ice
edge mowed 90 to 210 miles towards the
southpast, the average being sorne 140 miles.
See Fig. 7. The reason is clear. In stead of
east-northeast geostrophic wind of 10 to 12
knots, which is the mean winter wind here, a
clue west wind of 13 knots is now the average
i'or February. All inward thrust by the wind
Fig. 7. The ice edge at the end of the months
December, January and February, 1965.
is gone and a strong outward push lias taken
its place. Actually, the outward movement of
the ice seems greater than to be causecl by
the wind alone, especially where the ice tongue
extends south along the east coast. This is
only natural, because it is here the East Ice-
landic Current would be expectecl to play its
greatest role.
After the arrival of the ice to the coasts its
movements can be followed front day to day.
It becomes apparent that besides ticlal cur-
rents the wind is the major factor in moving
it about. Fig. 9 shows graphs of the north
and west wind components at the nortlieast
coast of Iceland where the mid point is at
66.5° N and 16° W. The graphs are drawn
from three clays means, and one can almost
use them as a diary on the movements of the
ice. With the February graphs there is also
drawn the west wind component between the
stations Galtarviti in Northwest Iceland ancl
Cape Tobin in Northeast Greenland. The
great similarity between this curve and that
for the west wind at the coast of Northeast
Iceland shows that a good estimate of the
winds north of Iceland can be formed by mea-
suring the gradient off the northwest coast.
Here the movements of the ice at the shore;
of Iceland will not be followed closelv. It
wandered away with offshore winds and canie
in again with onshore winds. After a few days
of northeasterly winds in March it reached its
southernmost position at the east coast due
east of Berufjörður. It blocked the way for all
navigation at Langanes from the 18th of
March to the 22nd of April. Off Cape Horn
navigation was never hindered for any length
of time but sailing was oftcn difficult in
Húnaflói. In May the wind remainecl easterly
74 JÖKULL 19. ÁR