Jökull - 01.12.1969, Blaðsíða 110

Fig. 2.
S = snow limit in Norway (D. Liestöl; quoted
from Schwarzbach (1961), Fig. 115).
I = virtual dipole moment of the earth in units
of 1025 gauss cm3, after Doell (1969).
thesis of Donn and Ewing (1966). The area
north of latitude 66° is 1 /23 of the earth’s
surface and the insolation in that area is a far
less part of the whole. Can changes of ice cover
in the Arctic Ocean then affect seriously the
whole energy balance of the earth? By winter
temperatures of —40° to —50° C, by the inflow
of fresh water giving a low-salinity surface lay-
er, how is an ice-free Arctic Ocean possible
now or some 70 thousand years ago? These
questions should show how difficult it is for
the author to accept the hypothesis of Donn
and Ewing as a primary cause.
Finally, the latter possibility in A-4, a, self-
regulated states in the stratosphere, is left with
a question mark. Thus, we have advanced
three primary terrestrial hypotheses, but all
subject to further research, and C-1 whose
value for the long Pleistocene fluctuations
could possibly be tested by lunar and Mart-
ian research. d'here are some indications on
the moon of changes corresponding to the
terrestrial ones in which case C-1 would be
substantiated.
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Doell, R. R. 1969: History of the Geomagnetic
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Donn, W. L. and M. Ewing. 1966: A theory of
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106 JÖKULL 19. ÁR