CLIMATOLOGICAL PROBLEMS IN THE ARCTIC AND SUB-ARCTIC 
ringed by aerological stations and passing annually 
through the cycle from completely frozen to completely 
ice-free, seems an obvious laboratory for such a study. 
3. The characteristics of coastal ice, especially in 
harbours, is another topic worthy of study by the 
climatologist. At present the relation between climate 
and freeze-up, breakup, and thickness of coastal ice 
is only qualitatively understood. In 1943 the United 
States Air Weather Service began serious observation 
of both fresh water and sea ice, as well as of snow cover, 
at all its Canadian, Alaskan, and Greenland stations. 
It is to be hoped that these records will ultimately be- 
come available to research-workers. 
THE PROBLEM OF GREENLAND 
Most problems of arctic climatology are hemispheric: 
they are widespread in character, and are as much 
problems in Siberia, for example, as they are in Alaska. 
Greenland presents us with an entirely distinct set of 
questions, to which highly controversial answers are 
sometimes given. Since many of these problems are 
critically important to students of Pleistocene glaci- 
ation and to glaciologists as well as to climatologists, 
they demand a brief review here. 
The central icecap of Greenland, occupying as it 
does the great bulk of the land mass, has remained 
throughout the past hundred years a virtual blank on 
the weather map. Our knowledge of its climate rests 
upon the reports of the handful of explorers who have 
crossed it, and on the two or three brief periods of ob- 
servation by icecap meteorological stations. In place 
of real knowledge, we have had a generation or more 
of heated controversy concerning the theory of the 
so-called “glacial anticyclone.”” This controversy has 
recently [26] been likened to a debate between ex- 
plorers (who have seen for themselves) and absentee 
meteorologists (who persist in ignoring the evidence 
provided by the explorers). This is a grave oversimplifi- 
cation, but it does contain the seeds of the truth; the 
controversy wages over different interpretations of the 
evidence, that of the explorers—which is essentially in- 
expert—and that of the meteorologists, many of whom 
have had practical experience in Greenland. 
Nearly all the explorers who have crossed or pene- 
trated the icecap refer [47] to a remarkable wind and 
weather régime. They speak of strong and monotonously 
regular downslope winds blowing out from the central 
core, and pouring out through the coastal fjords to the 
surrounding seas. Peary [47] described the flow as being 
analogous to the flow of water down a slope. In a sense 
these stories represent very large scale parallels of the 
Gletscherwinde of the Alps. 
In 1910 the well-known geologist, W. H. Hobbs, 
presented in its earliest form the theory of the glacial 
anticyclone [22], by which he explained not only the 
Greenland climate but also the general characteristics 
of Pleistocene icecap climates. With added experience 
he published a greatly expanded version of this theory 
in his book The Glacial Anticyclones [23] and his views 
have remained substantially unchanged ever since [25]. 
961 
Though he has been hotly attacked, Hobbs has main- 
tained his position with great tenacity; the “glacial 
anticyclone” has become an established part of the 
legend of Pleistocene geology, and has coloured the 
thinking of arctic specialists for a generation. 
We may summarise the main features of Hobbs’s 
theory as follows: 
1. An ice surface is a good reflector and a good radi- 
ator; hence the air resting on the icecap should be 
subject to intense radiative cooling which cannot be 
counteracted by absorption of insolation. 
2. The cooling must lead first to an accumulation 
of very cold air in the central regions of the cap, and 
hence to rising pressure. Finally, the accumulated mass 
of cold air must break out to the coast in a spectacular 
downslope surge or “‘stroph”’ of the glacial anticyclone. 
To replace the outflowing air, general subsidence be- 
gins, and at very high levels there are radially inflowing 
winds. The subsiding air, however, is warmed thermo- 
dynamically, and eventually destroys the cold of the 
central regions. In a few days the “‘stroph”’ is finished, 
and the icecap settles down to a fresh period of refrigera- 
tion, after which the cycle is repeated. 
3. In effect, this view postulates that a fixed, per- 
manent anticyclone lies over the icecap; in it, the normal 
clockwise circulation of the anticyclone is replaced by 
a gigantic downhill, gravity-impelled divergence of the 
chilled surface air. The presence of such an anticyclone 
over the cap must plainly inhibit the passage of cy- 
clones, and it is a fundamental tenet of Hobbs’s theory 
that cyclones do not penetrate more than a few miles 
inland. He has published several papers [27] designed 
to prove this. 
4. The alimentation of the icecap, however, presents 
a problem, for if cyclones do not cross it, from where 
does the snow come to make good the large annual loss 
by ablation? In Hobbs’s view, hoarfrost, not snow, 
feeds the Greenland ice, as it did the Pleistocene sheets. 
The radiative cooling of the subsiding air at the ice 
surface causes the condensation of huge quantities of 
hoarfrost, enough to make good all losses by ablation. 
5. Hobbs’s final point—and in some ways the most 
pregnant—is that the “‘strophs” of the glacial anti- 
cyclone set off the main frontal cyclones of the Atlantic; 
the icecap acts, in fact, as the ‘‘North Pole of the 
winds,” to use his own picturesque phrase. At all 
seasons the air over the icecap is the coldest in the 
Arctic, and hence must replace the polar cap itself as 
the source of true arctic outbreaks. 
All aspects of this remarkable theory have been hotly 
debated for more than a generation. It is not too much 
to claim that Hobbs’s work was directly responsible 
for the bulk of the exploration of the Greenland interior 
carried out after World War I. The University of 
Michigan sent several expeditions to the west coast 
between 1926 and 1933 under the leadership of Hobbs 
himself and L. Gould [40]. These expeditions set up 
stations both on the coast and on the icecap, carrying 
out an elaborate series of surface and upper-air ob- 
servations. In 1930-31 Alfred Wegener organised a re- 
